Recyclable eva foams

Abstract

Provided is a recycling foaming composition for making a recycled foamed EVA copolymer article. The recycling foaming composition comprises a scrap foamed EVA copolymer product and a virgin foaming composition, which comprises an EVA copolymer and a metal ion. The virgin foaming composition further comprises a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups. Further disclosed are a recycled foamed EVA copolymer article and a method of making a recycled foamed EVA copolymer article, among other aspects.

Description

[0001] Recyclable EVA Foams

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to foaming compositions for making EVA copolymer articles, and to EVA copolymer articles made from these foams, including their use in footwear applications.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] EVA copolymer articles are used in many industries and for many different applications, including soles for shoes. One major challenge facing the sustainability of articles containing EVA foam (such as footwear articles) is that conventional EVA foams cannot be non-destructively recycled, which results in limited end-of-life options for these footwear items and the scrap EVA foam that is generated during manufacturing. Even though some reports of allegedly recyclable EVA foams are available, recycling technologies for EVA foams have been limited, as recycling EVA foams typically results in poorer physical properties and aesthetic appearance, particularly when adding high amounts of recycled content.

[0006] US 9,074,061 B2 describes an EVA foam recycling method that uses hydrogenated petroleum resins to compatibilize scrap EVA blended with virgin EVA. The patent shows that simply adding scrap EVA foam to virgin EVA results in foams with poor physical properties and aesthetics. However, after adding a certain amount of Struktol 60NS petroleum resin, foams of good physical properties could be made. CN 111218054 B also relates to a recyclable EVA foam material. However, the analysis of the compressive stress of the foams described in the document shows that the properties of the foams are very different from that of a conventional peroxide-cured EVA foam. After recycling, these properties change further, and are inconsistent with the original material.

[0007] The compositions and foamed articles described in the prior art have several disadvantages. For example, most compositions described in the prior art are not recyclable at all, or only to a limited extent. Even if some degree of recyclability may have been reported, the amount of scrap EVA that can be incorporated into the manufacturing of new EVA material is often strictly limited.

[0008] Furthermore, recycling of foamed EVA articles that were made using the prior art compositions and methods leads to a significant and undesirable alteration of the properties, such that the properties are no longer consistent with the original material. For example, when using prior art EVA compositions, recycling often leads to a significant increase in density of the EVA foam. A further challenge is that the foamed EVA material is often no longer closed cell and may even display major physical inhomogeneity, including holes or cracks. Other material properties that may be affected include tear strength, elastic modulus, hardness, shrinkage, compression set and compression strength.

[0009] In conclusion, there is a need to provide improved EVA foaming compositions and, in particular, to improve recyclability of EVA foams.

[0010] SUMMARY OF THE DISCLOSURE

[0011] It is a general object of the present disclosure to address at least some of the disadvantages of the prior art. It is a particular object in at least some embodiments to provide a recyclable EVA foaming composition and to provide recyclable foamed EVA copolymer articles. Preferably, it would be possible to incorporate a high amount of scrap EVA into the manufacturing of new EVA material. It is a further object in at least some embodiments to provide foamed EVA copolymer articles incorporating scrap EVA, which display advantageous physical properties. Preferably, the physical properties of such recycled foamed EVA copolymer articles should be consistent with the original material. For example, it would be desirable that the recycled EVA foamed articles would display similar physical properties as the original material.

[0012] The general object is solved by different aspects of the present disclosure. Further advantageous embodiments are described herein.

[0013] In a first aspect, the present disclosure provides, among other aspects and embodiments, a virgin foaming composition for making a virgin foamed ethylene vinyl acetate (EVA) copolymer article. The virgin foaming composition comprises an ethylene vinyl acetate (EVA) copolymer. The virgin foaming composition further comprises a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups. The virgin foaming composition further comprises a metal ion.

[0014] One advantage of the virgin foaming composition is that it is suitable for making a foamed EVA copolymer article incorporating scrap EVA foam, such as a scrap foamed EVA copolymer product. In particular, the composition allows EVA foams to be produced with a high ratio of scrap EVA to virgin EVA.

[0015] A further advantage is that the composition allows stable closed-cell EVA foams to be produced with particularly low amounts of peroxide added, which results in fewer permanent carbon-to-carbon crosslinks and improved recyclability of the product. Without wishing to be bound to a theory, and solely to illustrate a potential explanation applicable to at least some embodiments of the composition, the carboxylate / carboxylic acid groups may form a salt in situ with the metal ion (e.g. zinc oxide added as an activator). Interactions between the ions in the melt state increase the polymer’s viscosity compared to EVA and allow gas bubbles to be stabilized. This reduces the need for high amounts of crosslinking agent (e.g. peroxides), which are normally necessary to increase melt viscosity during foam production. Because less crosslinking agent can be employed, the amount of permanent carbon-carbon crosslinks can be reduced, which increases recyclability.

[0016] In a second aspect, the present disclosure provides a method of making a virgin foamed EVA copolymer article. This method comprising the steps of: a) providing the virgin foaming composition according to any one of the embodiments described herein; b) heating and / or compressing the provided virgin foaming composition to a temperature and / or pressure sufficient to obtain crosslinking of the virgin foaming composition; c) forming the crosslinked composition into an article, thereby obtaining the virgin foamed EVA copolymer article.

[0017] In a third aspect, the present disclosure provides a virgin foamed EVA copolymer article, which typically comprises a crosslinked reaction product of the virgin foaming composition of any of the embodiments described herein. The virgin foamed EVA copolymer article may in some embodiments be made using any of the embodiments of the method of making a virgin foamed EVA copolymer article described herein. In a fourth aspect, the present disclosure provides a recyclate for making a recycled foamed EVA copolymer article. The recyclate comprises the virgin EVA copolymer article according to any of the embodiments described herein.

[0018] In a fifth aspect, the present disclosure provides the use of the recyclate described in the previous paragraph for making a recycled foamed EVA copolymer article.

[0019] In a sixth aspect, the present disclosure provides a recycling foaming composition for making a recycled foamed EVA copolymer article. The recycling foaming composition comprises a scrap foamed EVA copolymer product and a virgin foaming composition. The virgin foaming composition comprises a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups. The virgin foaming composition further comprises a metal ion and an EVA copolymer.

[0020] In a seventh aspect, the present disclosure provides a method of making a recycled foamed EVA copolymer article from the recycling foaming composition according to any of the embodiments described herein, wherein the method comprises foaming the virgin foaming composition in the presence of the scrap foamed EVA copolymer product.

[0021] In an eighth aspect, the present disclosure provides a recycled foamed EVA copolymer article, which comprises a crosslinked reaction product of the recycling foaming composition according to any of the embodiments described herein.

[0022] In a ninth aspect, the present disclosure provides the use of EMAA copolymer or ionomer or of EAA or ionomer or of a mixture thereof in a foaming composition for enhancing the recyclability of a foamed EVA copolymer article formed from the foaming composition, wherein the foaming composition comprises an EVA copolymer and a metal ion, preferably a zinc ion. It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

[0023] BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The disclosure described herein will be more fully understood from the detailed description given herein below and the accompanying drawings, which should not be considered limiting to the disclosure described in the appended claims. The drawings show:

[0025] Fig. 1 Shows analytical data relating to EVA copolymer, namely the1H NMR spectrum of EVA (Fig. 1A) and the size exclusion chromatography (SEC) trace of

[0026] EVA (Fig. 1 B);

[0027] Fig. 2 shows the Asker C hardness of different foams;

[0028] Fig. 3 shows the density of different foams;

[0029] Fig. 4 shows the shrinkage of different foams;

[0030] Fig. 5 shows the compression set data for different foams;

[0031] Fig. 6 shows the compression strength for different foams;

[0032] Fig. 7 shows the stress-strain curve for the foams of examples 1a-1d; Fig. 8 shows the stress-strain curve for the foams of examples 2a-2d;

[0033] Fig. 9 shows the stress-strain curve for the foams of examples 3a-3d;

[0034] Fig. 10 shows photographs of samples 1a and 1d;

[0035] Fig. 11 shows photographs of samples 2a and 2d; Fig. 12 shows photographs of samples 3a and 3d.

[0036] DETAILED DESCRIPTION OF THE DISCLOSURE

[0037] Reference will now be made in detail to certain embodiments. It is noted that embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

[0038] Definitions

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure pertains. Otherwise, certain terms used herein have the meanings as set forth in the specification.

[0040] As used herein and in the appended claims, the term "copolymer" means a polymer polymerized from two or more monomers and includes terpolymers. In some embodiments, the “copolymer” may optionally be a polymer polymerized from exactly two monomers, as described herein below. Ethylene vinyl acetate (EVA) is a copolymer of ethylene and vinyl acetate.

[0041] As used herein and in the appended claims, the term “(meth)acrylate” refers to methacrylate, acrylate or a mixture thereof. Similarly, the term “(meth)acrylic acid refers to methacrylic acid, acrylic acid or a mixture thereof.

[0042] As used herein and in the appended claims, the terms “comprises”, “includes”, “has”, “contains” or any other variation thereof, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers and are intended to be non-exclusive or open-ended. For example, a composition, a method or an article, that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, method or article.

[0043] As used herein and in the appended claims, the term “consists of’ or variations indicate the inclusion of any recited integer or group of integers, but that no additional integer or group of integers can be added to the specified method, structure, or composition.

[0044] As used herein and in the appended claims, the term “from X to Y”, when used to define a numerical range (where X and X are placeholders for the respective values), includes both the value X, the value Y, and all values in between. Thus, by way of example, the term “from 2 to 10 apples” includes embodiments of 2 apples or 10 apples, as well as embodiments of 3, 4, 5, 6, 7, 8 or 9 apples.

[0045] Virgin Foaming Composition

[0046] In a first aspect, the present disclosure provides, among other aspects and embodiments, a virgin foaming composition for making a virgin foamed ethylene vinyl acetate (EVA) copolymer article. The virgin foaming composition comprises an ethylene vinyl acetate (EVA) copolymer. The virgin foaming composition further comprises a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups. The virgin foaming composition further comprises a metal ion.

[0047] First Polymer

[0048] In some embodiments, the first polymer is a first copolymer (or ionomer) formed from at least a first monomer and a second monomer. Depending on the application, the first copolymer (or ionomer) may optionally comprise a third monomer and possibly even further monomers. In some embodiments, however, the first copolymer (or ionomer) essentially consists of the first monomer and the second monomer and may optionally further comprise a metal ion, e.g. to form an ionomer. Depending on the application, different copolymers (or ionomers) may be used. For example, the first copolymer (or ionomer) may be a block copolymer, an alternating copolymer, a random copolymer or a graft copolymer.

[0049] In some embodiments, the second monomer comprises a carboxylic acid group or a carboxylate group. It is understood that the carboxylic acid group or the carboxylate group of the second monomer may correspond to the plurality of carboxylic acid groups and / or carboxylate groups of the first polymer.

[0050] In some embodiments, the first monomer is hydrophobic. In some embodiments, the first monomer is CHR=CHR’, preferably CHR=CH2, wherein R and R’ are independently from each other selected from the group consisting of H, linear or branched C1-4 alkyl and phenyl. In some embodiments, the first monomer is CHR=CH2, wherein R is selected from H, methyl and phenyl. In other words, in some embodiments, the first monomer is ethylene, propylene or styrene, preferably ethylene.

[0051] In some embodiments, the second monomer of the first polymer is CR”R”’=CHR””, preferably CR”R”’=CH2, wherein R” is -(CH2)n-COOH or-(CH2)n-COO_, wherein n is selected from 0 to 5, and wherein R’” and R”” are independently of each other selected from H, linear or branched C1-4 alkyl, -Cl and -(CH2)m-COOH or -(CH2)m-COO“, wherein m is selected from 0 or 1. Preferably, n is 0 and m is 0. In some embodiments, the second monomer is CR”R”’=CH2, wherein R” is -(CH2)n-COOH or -(CH2)n-COO“, wherein n is selected from 0 or 1 , preferably 0, and wherein R’” is H or methyl. In some embodiments, n is 0 and R’” is methyl. In some embodiments, n is 0 and R’” is H. It is understood that when R” is -(CH2)n-COO“, the anion is typically associated with a counter-cation. The counter-cation may e.g. be a metal counter-cation.

[0052] In some embodiments, the first polymer is selected from:

[0053] - ethylene methacryclic acid (EMAA) copolymer or ionomer;

[0054] - or an ethylene acrylic acid (EAA) copolymer or ionomer;

[0055] - or a mixture thereof.

[0056] It is understood that the “mixture thereof” means that the first polymer may be a mixture of EMAA copolymer and EMAA ionomer, or it may be a mixture of EMAA copolymer and EAA copolymer, or it may be a mixture of EMAA copolymer and EAA ionomer, or it may be a mixture of EMAA ionomer and EAA copolymer, or it may be a mixture of EMAA ionomer and EAA ionomer, or it may be a mixture of EAA copolymer and ionomer. In some embodiments, the first polymer may even be a mixture including three or further of these components. Preferably, the first polymer may be a mixture of EMAA (either copolymer and / or ionomer) and EAA (either copolymer and / or ionomer).

[0057] In some embodiments, the first polymer is an EMAA copolymer or ionomer, preferably an EMAA copolymer. In some embodiments, the EMAA copolymer or ionomer, respectively, or the EAA copolymer or ionomer, comprises from 5 wt.-% to 40 wt.-%, preferably from 5 wt.-% to 25 wt.- %, more preferably from 10 wt.-% to 20 wt.-%, more preferably 15 wt.-%, combined methacrylic acid and methacrylate, respectively, or combined acrylic acid and acrylate. For example, in some embodiments, the EMAA copolymer or ionomer comprises from 5 wt.-% to 40 wt.-%, preferably from 5 wt.-% to 25 wt.-%, more preferably from 10 wt.-% to 20 wt.-%, more preferably 15 wt.-%, combined methacrylic acid and methacrylate. “Combined methacrylic acid and methacrylate” means that in these embodiments, the combined weight of methacrylic acid and methacrylate lies in the indicated ranges. Alternatively or in combination, in some embodiments, the EAA copolymer or ionomer comprises from 5 wt.-% to 40 wt.-%, preferably from 5 wt.-% to 25 wt.-%, more preferably from 10 wt.-% to 20 wt.-%, more preferably 15 wt.-%, combined acrylic acid and acrylate. Similarly, “combined acrylic acid and acrylate” means that in these embodiments, the combined weight of acrylic acid and acrylate lies in the indicated ranges.

[0058] In some embodiments, the virgin foaming composition comprises the first polymer in an amount of at least 1 wt.-%, preferably at least 3 wt.-%, more preferably from 3 wt.-% to 20 wt.-%, even more preferably from 4 wt.-% to 10 wt.-%, with respect to the weight of EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition). In some embodiments, the virgin foaming composition comprises the first polymer in an amount of up to 10 wt.-%, such as up to 8 wt.-%, e.g. up to 6 wt.-%, with respect to the weight of EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition). In some embodiments, the virgin foaming composition comprises the first polymer in an amount from 3 wt.-% to 10 wt.-%, e.g. from 3 wt.-% to 9 wt.-%, such as from 3 wt.-% to 8 wt.-%, for example from 3 wt.-% to 7 wt.-%, with respect to the weight of EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition). Depending on the application, the amount of the first polymer in the composition may also be defined with respect to the weight of the virgin foaming composition. In some embodiments, the virgin foaming composition comprises the first polymer in an amount of at least 1 wt.-%, preferably at least 3 wt.-%, more preferably at least 4 wt.-%, with respect to the total weight of the virgin foaming composition. In some embodiments, the virgin foaming composition comprises the first polymer in an amount of up to 15 wt.-%, preferably up to 12 wt.-%, more preferably up to 9 wt.-%, with respect to the total weight of the virgin foaming composition. In some embodiments, the virgin foaming composition comprises the first polymer in an amount from 3 wt.-% to 15 wt.-%, preferably from 3 wt.- % to 10 wt.-%, more preferably from 3 wt.-% to 9 wt.-%, with respect to the total weight of the virgin foaming composition.

[0059] In some embodiments, the first polymer is an ionomer. For example, in some embodiments, in the ionomer, the metal ion is a counterion to the carboxylate groups.

[0060] In some embodiments, the first polymer has a melt flow index (MFI) of at least 15.000 g / 10 min (190 °C / 2.16 kg), preferably of at least 20.000 g / 10 min (190 °C / 2.16 kg), more preferably of at least 25.000 g / 10 min (190 °C / 2.16 kg). In some embodiments, the first polymer has a melt flow index up to 40.000 g / 10 min (190 °C / 2.16 kg), preferably up to 35.000 g / 10 min (190 °C / 2.16 kg), more preferably up to 30.000 g / 10 min (190 °C / 2.16 kg). The ranges described in this paragraph preferably relate to embodiments in which the first polymer is not an ionomer, for example to those embodiments in which the first polymer is selected from EMAA copolymer, EAA copolymer or a mixture thereof.

[0061] In some embodiments in which the first polymer is an ionomer, the first polymer has a melt flow index (MFI) of at least 0.100 g / 10 min (190 °C / 2.16 kg), preferably of at least 0.300 g / 10 min (190 °C / 2.16 kg), more preferably of at least 0.500 g / 10 min (190 °C / 2.16 kg). In some embodiments in which the first polymer is an ionomer, the first polymer has a melt flow index of up to 10.000 g / 10 min (190 °C / 2.16 kg), preferably of up to 7.500 g / 10 min (190 °C / 2.16 kg), more preferably of up to 6.000 g / 10 min (190 °C / 2.16 kg).

[0062] In some embodiments, the first polymer has a density from 0.8 g / cm3to 1.05 g / cm3, preferably from 0.9 g / cm3to 0.98 g / cm3, more preferably from 0.92 g / cm3to 0.96 g / cm3. Alternatively or in combination, in some embodiments, the first polymer has a melting point from 80 °C to 110 °C, preferably from 85 °C to 99 °C, as determined according to ASTM D3418-21.

[0063] Crosslinking Agent

[0064] Depending on the application, the virgin foaming composition may further comprise a radical crosslinking agent. For example, the virgin foaming composition may comprise the radical crosslinking agent in an amount of less than 1 wt.-%, preferably from 0.05 wt.-% to 0.70 wt.-%, more preferably from 0.10 wt.-% to 0.5 wt.-%, even more preferably from 0.15 wt.-% to 0.40 wt.-%, with respect to the weight of EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition).

[0065] In some embodiments, the virgin foaming composition comprises the radical crosslinking agent in an amount of less than 1 wt.-%, preferably from 0.05 wt.-% to 0.6 wt.-%, more preferably from 0.08 wt.-% to 0.4 wt.-%, even more preferably from 0.15 wt.-% to 0.30 wt.-%, with respect to the total weight of the virgin foaming composition. In some embodiments, the virgin foaming composition comprises the radical crosslinking agent in an amount from 0.15 wt.-% to 0.30 wt.-%, with respect to the total weight of the virgin foaming composition.

[0066] In some embodiments, the virgin foaming composition is essentially free of radical crosslinking agents. For example, the virgin foaming composition may comprise less than 0.10 wt.-%, preferably less than 0.05 wt.-%, of crosslinking agent with respect to the total weight of the virgin foaming composition. In some embodiments, the virgin foaming composition comprises less than 0.01 wt.-%, preferably less than 0.001 wt.-%, e.g. less than 0.0001 wt.-%, of crosslinking agent with respect to the total weight of the virgin foaming composition.

[0067] Depending on the application, different radical crosslinking agents may be used. In some embodiments, the radical crosslinking agent is a peroxide, preferably an organic peroxide, more preferably bis(tert-butylperoxyisopropyl)benzene (BIPB) or dicumyl peroxide, more preferably BIPB. In some embodiments, the radical crosslinking agent is selected from one or more of the following : dicumyl peroxide, a,a'-di-(t-butylperoxy)diisopropy- Ibenzene; 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane; 2,5-dimethyl-2,5-di-(t-bu- tylperoxy)hexyne-3; n-Butyl 4,4-di-(t-butylperoxy)-valerate; 1 ,1-bis-(t-butylperoxy)-3,3,5- trimethylcyclohexane; and t-butyl perbenzoate.

[0068] Metal Ion

[0069] The virgin foaming composition also comprises a metal ion. The metal ion is typically configured to form an ionic bond together with the carboxylate groups of the first polymer. For example, the metal ion may be a zinc ion, which may e.g. form an ionic bond with the (meth)acrylate groups in EMAA / EAA.

[0070] It is understood that the metal ion is typically present together with a suitable counteranion. Depending on the application, different counter-anions may be used. In some embodiments, the metal ion is present in the virgin foaming composition in the form of a metal oxide. In some embodiments, the metal ion is present in the virgin foaming composition in the form of a salt, wherein e.g. the metal ion is ionically bonded to an inorganic anion. For example, the metal ion may e.g. be present in the virgin foaming composition in the form of a metal halide, such as a metal chloride. In some embodiments, the metal ion in the virgin foaming composition is ionically bonded to an organic anion. For example, the metal ion may e.g. be ionically bonded to stearate. In some embodiments, the metal ion in the virgin foaming composition is ionically bonded to the carboxylate groups of the first polymer. For example, in some embodiments, the metal ion is ionically bonded to the (meth)acrylate groups. In other words, the first polymer may in this embodiment be an ionomer formed from the metal salt and EMAA, EAA or a mixture thereof.

[0071] In some embodiments, the metal ion is selected from one or more of the following: zinc ion, sodium ion, and magnesium ion, preferably zinc ion. In some embodiments, the virgin foaming composition comprises the metal ion in the form of zinc oxide or zinc stearate, preferably zinc oxide. For example, the metal ion may be comprised in the virgin foaming composition in the form of an activator. Thus, for example, the composition may further comprise an activator comprising the metal ion.

[0072] Depending on the application, the virgin foaming composition may comprise the metal ion in different quantities. In some embodiments, the virgin foaming composition comprises at least 0.0001 wt.-%, e.g. at least 0.001 wt.-%, such as at least 0.01 wt.-%, such as at least 0.1 wt.-%, of the metal ion with respect to the total weight of the virgin foaming composition.

[0073] EVA Copolymer

[0074] The virgin foaming composition further comprises an EVA copolymer. The EVA copolymer may optionally be labelled as second polymer. Depending on the application, different EVA copolymers may be used.

[0075] In some embodiments, the virgin foaming composition comprises the EVA copolymer in an amount of at least 50 wt.-%, preferably at least 70 wt.-%, more preferably from 75 wt.- % to 97 wt.-%, even more preferably from 78 wt.-% to 95 wt.-%, with respect to the total weight of the virgin foaming composition. In some embodiments, the virgin foaming composition comprises the EVA copolymer in an amount from 80 wt.-% to 93 wt.-% with respect to the total weight of the virgin foaming composition.

[0076] In some embodiments, the EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition) comprises from 10 wt.-% to 70 wt.-%, preferably from 10 wt.- % to 50 wt.-%, more preferably from 15 wt.-% to 40 wt.-%, more preferably from 20 wt- % to 35 wt.-%, more preferably from 25 wt.-% to 31 wt.-%, vinyl acetate.

[0077] In some embodiments, the EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition) has a number average molecular weight ( / W„) from 60,000 g / mol to 120,000 g / mol, preferably from 70,000 g / mol to 110,000 g / mol, more preferably from 80,000 g / mol to 100,000 g / mol, even more preferably of 90,000 g / mol.

[0078] In some embodiments, the EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition) has a melt flow index (MFI) of at least 0.500 g / 10 min (190 °C / 2.16 kg), preferably at least 1.000 g / 10 min (190 °C / 2.16 kg), more preferably at least 2.000 g / 10 min (190 °C / 2.16 kg), more preferably at least 3.000 g / 10 min (190 °C / 2.16 kg). In some embodiments, the EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition) has a melt flow index (MFI) up to 20.000 g / 10 min (190 °C / 2.16 kg), preferably up to 15.000 g / 10 min (190 °C / 2.16 kg), more preferably up to 10.000 g / 10 min (190 °C / 2.16 kg), even more preferably up to 5.000 g / 10 min (190 °C / 2.16 kg). In some embodiments, the EVA copolymer has a melt flow index from 1.000 to 10.000 g / 10 min (190 °C / 2.16 kg), preferably from 2.000 to 5.000 g / 10 min (190 °C / 2.16 kg), even more preferably from 3.000 to 4.000 g / 10 min (190 °C / 2.16 kg). In some embodiments, the EVA copolymer (i.e. the EVA copolymer comprised in the virgin foaming composition) has a polydispersity index (£>) from 1.50 to 4.00, preferably from 2.00 to 3.62, more preferably from 2.30 to 3.32.

[0079] Blowing Agent

[0080] In some embodiments, the virgin foaming composition further comprises a blowing agent. In some embodiments, the blowing agent comprises or consists of a diazocarbamide, preferably azodicarbonamide.

[0081] In some embodiments, the blowing agent is selected from one or more of the following: azodicarbonamide, 2,2'-azobisisobutynotrile, azohexahydrobenzonitrile, diazodiaminobenzene, and other azo compounds; benzenesulfonylhydrazide, benzene-1 ,3-sulfonyl- hydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, diphenyloxide-4,4'-disulfonylhydra- zide, 4,4'-oxybis(benzenesulfonyl hydrazide), p-toluenesulfonylhydrazide, and other sulfonylhydrazide compounds; terephthalazide, p-t-butylbenzazide, and other azide compounds; and sodium bicarbonate, ammonium bicarbonate, ammonium carbonate, and other carbonate compounds.

[0082] In some embodiments, foaming auxiliary agents can be added to the virgin foaming composition, e.g. to lower the decomposition temperature of the blowing agent. The foaming auxiliary agents can e.g. be selected from one of more of the following: zinc white, zinc oxide, zinc stearate, zinc nitrate, zinc phthalate, zinc carbonate, phosphorous trichloride salt, tribasic zinc sulfate, and other inorganic salts; zinc fatty acid soaps, lead fatty acid soaps, cadmium fatty acid soaps, and other metal soaps; boric acid, oxalic acid, succinic acid, adipic acid, and other acids; urea, ethanolamine, glucose, and glycerin.

[0083] In some embodiments, a foaming inhibitor is added to the virgin foaming composition, e.g. to raise the decomposition temperature of the thermally decomposable blowing agent. The foaming inhibitors can e.g. be selected from one or more of the following: maleic acid, fumaric acid, phthalic acid, maleic anhydride, phthalic anhydride, and other organic acids; stearoyl chloride, phthaloyl chloride, and other halogenated organic acids; hydroquinone and other polyvalent alcohols; fatty acid amines, amides, oximes, isocyanates, and other organosulfur-containing compounds, phosphorous acid chlorides and other phosphoric acid salts; dibutyltin maleate, tin chloride, tin (II) sulfate, and other tin compounds; as well as hexachloropentadiene.

[0084] Compatibilizer

[0085] Depending on the application, it may or may not be advantageous to include compatibilizers in the virgin foaming composition. In some embodiments, the virgin foaming composition is essentially free of compatibilizers. In some embodiments, the virgin foaming composition may e.g. be essentially free of a hydrocarbon resin compatibilizer or a hydrogenated petroleum resin compatibilizer. Essentially free, in this context, may for example mean that the virgin foaming composition comprises the respective compatibilizers in an amount of less than 1 wt.-%, preferably less than 0.1 wt.-%, more preferably less than 0.01 wt.-%, even more preferably less than 0.001 wt.-%, even more preferably less than 0.0001 wt.-%, with respect to the total weight of the virgin foaming composition. In some embodiments, the virgin foaming composition may be entirely free of compatibilizers.

[0086] In some embodiments, however, the virgin foaming composition comprises at least one compatibilizer. Particularly good results were obtained when using paraffin oil as compatibilizer. Thus, in some embodiments, the virgin foaming composition comprises paraffin oil. As used herein, paraffin oil refers to a combustible hydrocarbon liquid which is derived from petroleum and which is labelled as “paraffin oil” in British English, and as “kerosene” in American English. For example, the paraffin oil may at least in some embodiments be composed of hydrocarbon molecules having from 6 to 20 carbon atoms per molecule. More preferably, the hydrocarbon molecules in paraffin oil may optionally predominantly have from 9 to 16 carbon atoms. In at least some embodiments, the paraffin oil has a flash point from 55 °C to 74 °C.

[0087] Composition

[0088] Depending on the application, the virgin foaming composition may comprise different components. For example, in some embodiments, the virgin foaming composition further comprises a crosslinking agent and / or a blowing agent and / or an activator. In some embodiments, the virgin foaming composition also comprises a solvent. Optionally, the virgin foaming composition may comprise even further components. However, in some embodiments, the virgin foaming composition essentially consists of the first polymer, the EVA copolymer, the metal ion, optionally the crosslinking agent, optionally the blowing agent, optionally the activator, optionally the solvent and optionally a filler.

[0089] In some embodiments, the composition further comprises a filler, which may e.g. be selected from the group consisting of magnesium carbonate, magnesium silicate, and calcium carbonate.

[0090] Method of making a virgin foamed EVA copolymer article

[0091] In a second aspect, the present disclosure relates to a method of making a virgin foamed EVA copolymer article. The method of making a virgin foamed EVA copolymer article comprises a) providing the virgin foaming composition according to any one of the embodiments described herein. The method further comprises b) heating and / or compressing the provided virgin foaming composition to a temperature and / or pressure sufficient to obtain crosslinking of the virgin foaming composition. The method further comprises c) forming the crosslinked composition into an article, thereby obtaining the virgin foamed EVA copolymer article. In this method, the virgin foaming composition provided in step a) may be the virgin foaming composition according to any of the embodiments described herein, in particular including but not limited to any embodiments described herein in the context of the first aspect of the disclosure.

[0092] The virgin foamed EVA copolymer article obtained from the method is crosslinked. Depending on the application, different crosslinks may be formed. For example, the virgin foamed EVA copolymer article may include ionic crosslinks and optionally also covalent crosslinks.

[0093] In some embodiments, the virgin foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between the metal ions and the carboxylate groups of the first polymer. These ionic crosslinks may optionally be comprised by the crosslinks obtained in step b).

[0094] In some embodiments, copolymer chains of the first polymer may be crosslinked by the metal ions. This crosslinking may e.g. involve binding of the metal ions to the (methacrylate groups of the first polymer and / or to the (meth)acrylic acid groups of the first polymer. In those embodiments in which the crosslinks obtained in step b) include ionic crosslinks, these ionic crosslinks may either be newly formed in step b), or they may at least partially already have been present in the virgin foaming composition. For example, in some embodiments, the first polymer is an ionomer in which the metal ions are already ionically bonded to the (meth)acrylate groups. In these embodiments, step b) may optionally involve re-arrangement of the ionic bonds already present and optionally formation of further ionic bonds.

[0095] In some embodiments, the crosslinks obtained in step b) include covalent crosslinks, typically covalent crosslinks between copolymer chains of the EVA copolymer. These covalent crosslinks are typically formed by C-C bonds and / or C=C bonds, preferably by C-C bonds. The covalent crosslinks between copolymer chains of the EVA copolymer are typically newly formed during step b).

[0096] Depending on the application, different molding techniques may be used. In some embodiments, the virgin foaming composition is compression molded or injection molded. In some embodiments, in step b), the virgin foaming composition is compression molded and a mold is filled to a mold fill factor from 80 vol.-% to 95 vol.-%, preferably from 85 vol.-% to 93 vol.-%, more preferably 90 vol.-%, with respect to a total volume of the mold. Alternatively or in combination, in some embodiments, in step b) the virgin foaming composition is compression molded at a compression force of at least 10 kN, preferably at least 25 kN, more preferably from 35 kN to 65 kN.

[0097] Depending on the application, different temperatures and / or pressures may be used. In some embodiments, in step b) the virgin foaming composition is heated at a temperature of at least 100 °C, preferably at least 150 °C, more preferably from 150 °C to 220 °C. In some embodiments, in step b), the virgin foaming composition is heated at a temperature within the ranges indicated in the previous sentence for a duration of at least 100 seconds, preferably at least 300 seconds, more preferably for 400 seconds to 800 seconds.

[0098] In some embodiments, the virgin foaming composition comprises a blowing agent and the virgin foaming composition is heated and / or compressed to a temperature and / or pressure sufficient to activate the blowing agent to obtain foaming. For example, the activation of the blowing agent may comprise decomposition of the blowing agent. Depending on the application, the virgin foaming composition may comprise an activator, e.g. a blowing agent activator. The blowing agent activator may e.g. be configured to lower an activation temperature and / or activation pressure for decomposition of the blowing agent. Virgin foamed EVA copolymer article

[0099] In a third aspect, the present disclosure relates to a virgin foamed EVA copolymer article. The virgin foamed EVA copolymer article comprises a crosslinked reaction product of the virgin foaming composition of any of the embodiments described herein. In some embodiments, the virgin foamed EVA copolymer article consists of the crosslinked reaction product.

[0100] Since the virgin foamed EVA copolymer article comprises a crosslinked reaction product of the virgin foaming composition, it is understood that the embodiments described herein in the context of the virgin foaming composition (including but not limited to embodiments described in the context of the first aspect of the present disclosure) also apply analogously to the virgin foamed EVA copolymer article, unless specifically stated otherwise or unless the context clearly dictates otherwise, with the exception that in the virgin foamed EVA copolymer article, the virgin foaming composition is in a crosslinked, foamed state.

[0101] Thus, the crosslinked reaction product of the virgin foaming composition typically comprises a crosslinked foamed reaction product comprising:

[0102] - a first polymer comprising a plurality of carboxylic acid groups and / or carboxylate groups;

[0103] - an EVA copolymer and a metal ion.

[0104] In some embodiments, the first polymer is selected from: ethylene methacryclic acid (EMAA) copolymer or ionomer;

[0105] - or an ethylene acrylic acid (EAA) copolymer or ionomer;

[0106] - or a mixture thereof.

[0107] In some embodiments, the first polymer is an EMAA copolymer or ionomer, preferably an EMAA copolymer.

[0108] In a typical embodiment, at least the EVA copolymer in the crosslinked foamed reaction product is in a foamed and crosslinked state. Typically, the first polymer is also in a foamed and crosslinked state in the crosslinked foamed reaction product.

[0109] In some embodiments, the virgin foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between the metal ions and the carboxylate groups of the first polymer. For example, in some embodiments, copolymer chains of the first polymer are crosslinked by the metal ions in the virgin foamed EVA copolymer article. This crosslinking may e.g. involve binding of the metal ions to the (meth)acrylate groups of the first polymer.

[0110] In some embodiments, the virgin foamed EVA copolymer article comprises a plurality of covalent crosslinks between copolymer chains of the EVA copolymer. For example, the covalent crosslinks may be formed by C-C bonds or C=C bonds, preferably by C-C bonds.

[0111] In some embodiments, the virgin foamed EVA copolymer article has a density of less than 0.50 g / cm3, preferably less than 0.40 g / cm3, more preferably from 0.05 g / cm3to 0.30 g / cm3, more preferably from 0.15 g / cm3to 0.27 g / cm3, more preferably from 0.15 g / cm3to 0.23 g / cm3. In some embodiments, the virgin foamed EVA copolymer article has a density of less than 0.30 g / cm3, preferably less than 0.25 g / cm3, for example less than 0.20 g / cm3. In some embodiments, the virgin foamed EVA copolymer article has a density of at least 0.05 g / cm3, preferably at least 0.10 g / cm3, more preferably at least 0.15 g / cm3.

[0112] In some embodiments, the virgin foamed EVA copolymer article has a hardness (Asker C) from 30 to 60, preferably from 40 to 52, as determined according to ASTM D2240 (version of 2004). In some embodiments, the virgin foamed EVA copolymer article has a hardness (Asker C) of at least 30, preferably at least 35, more preferably at least 40, as determined according to ASTM D2240 (version of 2004). In some embodiments, the virgin foamed EVA copolymer article has a hardness (Asker C) of up to 60, preferably up to 55, more preferably up to 52, e.g. up to 50, as determined according to ASTM D2240 (version of 2004).

[0113] In some embodiments, the virgin foamed EVA copolymer article has a compression set from 45% to 65%, such as from 50% to 65%, as determined according to ASTM D 395- B. In some embodiments, the virgin foamed EVA copolymer article has a compression set of at least 45%, preferably at least 50%, more preferably at least 55%, as determined according to ASTM D 395-B. In some embodiments, the virgin foamed EVA copolymer article has a compression set of up to 70%, preferably up to 65%, as determined according to ASTM D 395-B.

[0114] In some embodiments, the virgin foamed EVA copolymer article has a compression strength from 0.15 MPa to 0.30 MPa, preferably from 0.20 MPa to 0.25 MPa, as determined at 50% strain. In some embodiments, the virgin foamed EVA copolymer article has a compression strength of at least 0.10 MPa, preferably at least 0.15 MPa, more preferably at least 0.20 MPa, as determined at 50% strain. In some embodiments, the virgin foamed EVA copolymer article has a compression strength of up to 0.35 MPa, preferably up to 0.30 MPa, more preferably up to 0.25 MPa, as determined at 50% strain. The compression strength, as used herein, is determined at 50% strain, as is described in the example section (see section “Foam Test Methods” below).

[0115] In some embodiments, the foam is substantially closed cell. In other words, in some embodiments, the virgin foamed EVA copolymer article comprises substantially closed cell foam.

[0116] In some embodiments, the virgin foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole.

[0117] Depending on the application, the virgin foamed EVA copolymer article may comprise further components, e.g. additives. In some embodiments, the virgin foamed EVA copolymer article consists of the crosslinked reaction product of the virgin foaming composition.

[0118] Depending on the application, the virgin foamed EVA copolymer article can be made using different methods. In some embodiments, the virgin foamed EVA copolymer article is made using any of the embodiments of the method of making a virgin foamed EVA copolymer article described herein, in particular including but not limited to embodiments described herein in the context of the second aspect of the disclosure.

[0119] Recyclate for making a recycled copolymer article

[0120] A fourth aspect of the present disclosure relates to a recyclate for making a recycled foamed EVA copolymer article. The recyclate comprises the virgin foamed EVA copolymer article according to any of the embodiments described herein. In some embodiments, the recyclate consists of the virgin foamed EVA copolymer article. The virgin foamed EVA copolymer may be present in the recyclate in different forms. In some embodiments, the virgin foamed EVA copolymer is present in the recyclate in the form of a powder, pellets, granules or flakes. For example, in some embodiments, the powder, pellets, granules or flakes have a particle size not exceeding 5 mm, preferably not exceeding 2 mm. In some embodiments, the powder, pellets, granules or flakes pass through a sieve of mesh size 5 mm x 5 mm, preferably 1.5 mm x 1.5 mm.

[0121] Depending on the application, the recyclate may comprise foamed EVA copolymer articles of different recycling generations. For example, in some embodiments, the recyclate essentially consists of virgin foamed EVA copolymer article. In some embodiments, the recyclate further comprises at least some recycled foamed EVA copolymer article, as described in further detail below (cf. e.g. the eighth aspect of the disclosure). In some embodiments, the recyclate comprises at least some virgin foamed EVA copolymer article and at least some recycled foamed EVA copolymer article. For example, in some embodiments, the recyclate comprises at least 60 wt.-%, preferably at least 70 wt.-%, more preferably at least 80 wt.-%, of virgin foamed EVA copolymer article, and up to 40 wt.-%, preferably up to 30 wt.-%, more preferably up to 20 wt.-%, of recycled foamed EVA copolymer article, wherein the weight percentages refer to the to the total weight of the recyclate.

[0122] A further aspect of the present disclosure relates to a method of recycling a virgin foamed EVA copolymer article. The method may e.g. comprise the step of reducing the virgin foamed EVA copolymer article to small pieces to provide a recyclate. In some embodiments, the virgin foamed EVA polymer article is milled, preferably cryomilled, to provide the virgin foamed EVA polymer article in the form of a powder, pellets, granules or flakes. In some embodiments, the powder, pellets, granules or flakes have a particle size not exceeding 5 mm, preferably not exceeding 2 mm. For example, in some embodiments, the powder, pellets, granules or flakes pass through a sieve of mesh size 5 mm x 5 mm, preferably 1.5 mm x 1.5 mm.

[0123] A fifth aspect of the present of the present disclosure relates to the use of the recyclate according to any of the embodiments described herein, for making a recycled foamed EVA copolymer article.

[0124] It is understood that since the recyclate comprises the virgin foamed EVA copolymer article, the embodiments described herein in the context of the virgin foamed EVA copolymer article also apply analogously to the recyclate, unless specifically stated otherwise or unless the context clearly dictates otherwise. For example, it is understood that in particular the embodiments of the virgin foamed EVA copolymer article relating to the chemical composition and chemical characterization of the virgin foamed EVA copolymer article also apply analogously to the recyclate.

[0125] It is further understood that the recyclate, the method of recycling a virgin foamed EVA copolymer article, and the use of the recyclate are interconnected with each other. For example, the recyclate can be made using the method of recycling. Accordingly, the embodiments described in the context of the recyclate in general also apply analogously to the method of recycling and to the use of the recyclate, unless specifically stated otherwise or unless the context clearly dictates otherwise.

[0126] Recycling foaming composition

[0127] In a sixth aspect, the present disclosure provides a recycling foaming composition for making a recycled foamed EVA copolymer article. The recycling foaming composition comprises a scrap foamed EVA copolymer product. The recycling foaming composition further comprises a virgin foaming composition. The virgin foaming composition com- prises a metal ion and an EVA copolymer. The virgin foaming composition further comprises a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups.

[0128] Scrap foamed EVA copolymer product

[0129] In typical embodiments, the scrap foamed EVA copolymer product is in a foamed and crosslinked state. In some embodiments, the scrap foamed EVA copolymer product is essentially fully crosslinked. In some embodiments, the scrap foamed EVA copolymer product typically comprises a plurality of covalent crosslinks between copolymer chains of the EVA copolymer. For example, the covalent crosslinks may be formed by C-C bonds or C=C bonds, preferably C-C bonds.

[0130] Depending on the application, the recycling foaming composition may comprise different amounts of scrap foamed EVA copolymer product. In some embodiments, the recycling foaming composition comprises the scrap foamed EVA copolymer product in an amount of at least 3 wt.-%, preferably at least 6 wt.-%, more preferably 10 wt.-% or more, with respect to the total weight of the recycling foaming composition. In some embodiments, the recycling foaming composition comprises the scrap foamed EVA copolymer product in an amount of up to 70 wt.-%, preferably up to 60 wt.-%, more preferably up to 50 wt.- %, such as up to 40 wt.-%, with respect to the total weight of the recycling foaming composition. In some embodiments, the recycling foaming composition comprises the scrap foamed EVA copolymer product in an amount from 3 wt.-% to 50 wt.-%, preferably from 5 wt.-% to 45 wt.-%, more preferably from 10 wt.-% to 35 wt.-%, with respect to the total weight of the recycling foaming composition. In some embodiments, the recycling foaming composition comprises the scrap foamed EVA copolymer product in an amount from 15 wt.-% to 50 wt.-%, preferably from 20 wt.-% to 40 wt.-%, more preferably from 25 wt- % to 35 wt.-%, with respect to the total weight of the recycling foaming composition. Depending on the application, different scrap foamed EVA copolymer product may be used in the recycling foaming composition. In some embodiments, the scrap foamed EVA copolymer product is conventional EVA copolymer product, for example EVA copolymer product comprising predominantly or even exclusively covalent crosslinks. However, it is also possible to use other EVA copolymer products as scrap foamed EVA copolymer products in the recycling foaming composition. For example, in preferred embodiments, the scrap foamed EVA copolymer product comprises a plurality of ionic crosslinks formed by ionic bonds, e.g. ionic bonds between metal ions and carboxylate groups. For example, the scrap foamed EVA copolymer product may comprise recyclate as disclosed herein. In these embodiments, for example, the scrap foamed EVA copolymer product may comprise a plurality of ionic crosslinks formed by ionic bonds, e.g. ionic bonds between metal ions and carboxylate groups of the first polymer. In some embodiments, the ionic crosslinks may be formed by ionic bonds between the metal ions and the (meth)acrylate groups of the first polymer. It is understood that the scrap foamed EVA copolymer may comprise a plurality of covalent crosslinks and / or a plurality of ionic crosslinks as described above.

[0131] Depending on the application, the recyclate described herein may be used as scrap foamed EVA copolymer product in the recycling foaming composition. Accordingly, in some embodiments, the scrap foamed EVA copolymer product of the recycling foaming composition comprises or consists of the recyclate according to any of the embodiments described herein, in particular including but not limited to any of the embodiments described herein in the context of the fourth aspect of the present disclosure.

[0132] In some embodiments, the scrap foamed EVA copolymer product comprises or consists of the virgin foamed EVA copolymer article according to any of the embodiments described herein, in particular including but not limited to any of the embodiments described herein in the context of the third aspect of the present disclosure. For example, the scrap foamed EVA copolymer product may comprise the virgin foamed EVA copolymer article according to any of the embodiments described herein in an amount of at least 50 wt.- %, preferably at least 70 wt.-%, more preferably at least 80 wt.-%, even more preferably at least 90 wt.-%, such as at least 95 wt.-%, with respect to the total weight of the scrap foamed EVA copolymer product.

[0133] Virgin foaming composition

[0134] The recycling foaming composition further comprises a virgin foaming composition. It is understood that the virgin foaming composition is in an unfoamed state. The virgin foaming composition comprised in the recycling foaming composition can e.g. be the virgin foaming composition according to any of the embodiments described herein, in particular including but not limited to any of the embodiments described herein in the context of the first aspect of the present disclosure. Accordingly, the embodiments described herein for the virgin foaming composition in the context of the first aspect of the present disclosure are generally also embodiments of the virgin foaming composition as used in the recycling foaming composition, unless specifically stated otherwise or unless the context clearly dictates otherwise. In particular, it is understood that any numerical values or ranges that define embodiments of the virgin foaming composition and which are indicated with respect to the total weight of the virgin foaming composition in the context of the first aspect of the present disclosure are generally to be understood also with respect to the total weight of the virgin foaming composition when the virgin foaming composition is used in the recycling foaming composition.

[0135] In some embodiments, the recycling foaming composition comprises the virgin foaming composition in an amount of at least 50 wt.-%, preferably at least 60 wt.-%, more preferably at least 65 wt.-%, with respect to the total weight of the recycling foaming composition. In some embodiments, the recycling foaming composition comprises the virgin foaming composition in an amount from 50 wt.-% to 95 wt.-%, preferably from 60 wt.-% to 90 wt.-%, for example from 65 wt.-% to 90 wt.-%, with respect to the total weight of the recycling foaming composition.

[0136] Depending on the application, different first polymers may be used. In some embodiments, the first polymer is an ionomer. As an example, in the ionomer, the metal ion of the virgin foaming composition may e.g. be a counterion to the carboxylate groups of the first polymer of the virgin foaming composition.

[0137] In some embodiments, the first polymer is a first copolymer formed from at least a first monomer and a second monomer, wherein the second monomer comprises a carboxylic acid group and / or a carboxylate group. Preferably, the second monomer comprises a carboxylic acid group. In some embodiments, the first copolymer is formed from the first monomer, the second monomer and additionally a third monomer and optionally even a fourth monomer. However, in some embodiments, the first copolymer is formed from only the first and second monomers.

[0138] Different copolymers can be used. For example, the first copolymer can be a block copolymer, an alternating copolymer, a random copolymer or a graft copolymer.

[0139] In some embodiments, the first monomer is hydrophobic. In some embodiments, the first monomer is ethylene, propylene or styrene, preferably ethylene.

[0140] In some embodiments, the virgin foaming composition comprises the first polymer in an amount of at least 1 wt.-%, preferably at least 3 wt.-%, more preferably from 3 wt.-% to 20 wt.-%, even more preferably from 4 wt.-% to 10 wt.-%, with respect to the weight of the EVA copolymer comprised in the virgin foaming composition. In some embodiments, the virgin foaming composition comprises the first polymer in an amount of up to 10 wt- %, such as up to 8 wt.-%, e.g. up to 6 wt.-%, with respect to the weight of the EVA copolymer comprised in the virgin foaming composition. In some embodiments, the virgin foaming composition comprises the first polymer in an amount from 3 wt.-% to 10 wt.-%, e.g. from 3 wt.-% to 9 wt.-%, such as from 3 wt.-% to 8 wt.-%, for example from 3 wt.-% to 7 wt.-%, with respect to the weight of the EVA copolymer comprised in the virgin foaming composition.

[0141] Composition

[0142] Depending on the application, it may or may not be advantageous for the recycling foaming composition to include compatibilizers or not. In some embodiments, the recycling foaming composition is essentially free of compatibilizers. In some embodiments, the recycling foaming composition is essentially free of compatibilizers. In some embodiments, the recycling foaming composition may e.g. be essentially free of a hydrocarbon resin compatibilizer or a hydrogenated petroleum resin compatibilizer. Essentially free, in this context, may for example mean that the recycling foaming composition comprises the respective compatibilizers in an amount of less than 1 wt.-%, preferably less than 0.1 wt.-%, more preferably less than 0.01 wt.-%, even more preferably less than 0.001 wt- %, even more preferably less than 0.0001 wt.-%, with respect to the total weight of the recycling foaming composition. In some embodiments, the recycling foaming composition may be entirely free of compatibilizers.

[0143] In some embodiments, however, the recycling foaming composition comprises at least one compatibilizer. Particularly good results were obtained when using paraffin oil as compatibilizer. Thus, in some embodiments, the recycling foaming composition comprises paraffin oil. As used herein, paraffin oil refers to a combustible hydrocarbon liquid which is derived from petroleum and which is labelled as “paraffin oil” in British English, and as “kerosene” in American English. For example, the paraffin oil may at least in some embodiments be composed of hydrocarbon molecules having from 6 to 20 carbon atoms per molecule. More preferably, the hydrocarbon molecules in paraffin oil may optionally predominantly have from 9 to 16 carbon atoms. In at least some embodiments, the paraffin oil has a flash point from 55 °C to 74 °C.

[0144] Depending on the application, the recycling foaming composition may optionally comprise a radical crosslinking agent. Some of the numerical ranges of the crosslinking agent are already specified in the context of the first aspect of the disclosure, where they are typically given with respect to the total weight of the virgin foaming composition, which composition may e.g. be comprised in the recycling foaming composition. The amount of radical crosslinking agent may also be defined with respect to the total weight of the recycling foaming composition. Thus, some further embodiments are described hereinafter. They may be realized alternatively to or in addition to the embodiments previously described in the context of the first aspect of the present disclosure.

[0145] In some embodiments, the recycling foaming composition comprises the radical crosslinking agent in an amount of less than 1 wt.-%, preferably from 0.05 wt.-% to 0.6 wt.-%, more preferably from 0.08 wt.-% to 0.4 wt.-%, even more preferably from 0.10 wt.-% to 0.30 wt.-%, with respect to the total weight of the recycling foaming composition. In some embodiments, the recycling foaming composition comprises the radical crosslinking agent in an amount from 0.10 wt.-% to 0.28 wt.-%, with respect to the total weight of the recycling foaming composition.

[0146] In some embodiments, the recycling foaming composition and the scrap foamed EVA copolymer product together account for at least 80 wt.-%, preferably at least 90 wt.-%, more preferably at least 95 wt.-%, for example 100 wt.-%, of the recycling foaming composition. In some embodiments, the recycling foaming composition consists of the scrap foamed EVA copolymer product and the virgin foaming composition. In some embodiments, the virgin foaming composition and the scrap foamed EVA copolymer product are essentially separated or essentially blended.

[0147] Method of making a recycled foamed EVA copolymer article

[0148] In a seventh aspect, the present disclosure provides a method of making a recycled foamed EVA copolymer article from the recycling foaming composition of any of the embodiments described herein, in particular including but not limited to any of the embodiments described herein in the context of the sixth aspect of the present disclosure. The method of making a recycled foamed EVA copolymer article comprising foaming the virgin foaming composition (which is comprised in the recycling foaming composition) in the presence of the scrap foamed EVA copolymer product (which is comprised in the recycling foaming composition).

[0149] In some embodiments, the method of making a recycled foamed EVA copolymer article comprises a) providing the recycling foaming composition according to any one of the embodiments described herein. The method may further comprise b) heating and / or compressing the provided recycling foaming composition to a temperature and / or pressure sufficient to obtain crosslinking. The method may further comprise c) forming the crosslinked composition into an article, thereby obtaining the virgin foamed recycled copolymer article. Typically, in step b), the crosslinking obtained includes crosslinking of the virgin foaming composition comprised in the recycling foaming composition.

[0150] The recycled foamed EVA copolymer article obtained from the method is crosslinked. Depending on the application, different crosslinks may be formed. For example, the recycled foamed EVA copolymer article may include ionic crosslinks and optionally also covalent crosslinks. In some embodiments, the recycled foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between the metal ions and the carboxylate groups of the first polymer. These ionic crosslinks may optionally be comprised by the crosslinks obtained in step b).

[0151] In some embodiments, copolymer chains of the first polymer may be crosslinked by the metal ions. This crosslinking may e.g. involve binding of the metal ions to the (methacrylate groups of the first polymer. In those embodiments in which the crosslinks obtained in step b) include ionic crosslinks, these ionic crosslinks may either be newly formed in step b), or they may at least partially already have been present in the virgin foaming composition. For example, in some embodiments, the first polymer is an ionomer in which the metal ions are already ionically bonded to the (meth)acrylate groups. In these embodiments, step b) may optionally involve re-arrangement of the ionic bonds already present and optionally formation of further ionic bonds.

[0152] In some embodiments, the crosslinks obtained in step b) further include covalent crosslinks, typically covalent crosslinks between copolymer chains of the EVA copolymer. These covalent crosslinks are typically formed by C-C bonds or C=C bonds, preferably C-C bonds. These covalent crosslinks between copolymer chains of the EVA copolymer are typically newly formed during step b).

[0153] Depending on the application, different molding techniques may be used. In some embodiments, the recycling foaming composition is compression molded or injection molded. In some embodiments, in step b), the recycling foaming composition is compression molded and a mold is filled to a mold fill factor from 80 vol.-% to 95 vol.-%, preferably from 85 vol.-% to 93 vol.-%, more preferably 90 vol.-%, with respect to a total volume of the mold. In some embodiments, in step b) the recycling foaming composition is compression molded at a compression force of at least 10 kN, preferably at least 25 kN, more preferably from 35 kN to 65 kN.

[0154] Depending on the application, different temperatures and / or pressures may be used. In some embodiments, in step b) the recycling foaming composition is heated at a temperature of at least 100 °C, preferably at least 150 °C, more preferably from 150 °C to 220 °C. In some embodiments, in step b), the recycling foaming composition is heated at a temperature within the ranges indicated in the previous sentence for a duration of at least 100 seconds, preferably at least 300 seconds, more preferably for 400 seconds to 800 seconds.

[0155] In some embodiments, the recycling foaming composition comprises a blowing agent and the recycling foaming composition is heated and / or compressed to a temperature and / or pressure sufficient to activate the blowing agent to obtain foaming. For example, the activation of the blowing agent may comprise decomposition of the blowing agent. Depending on the application, the recycling foaming composition may comprise an activator, e.g. a blowing agent activator. The blowing agent activator may e.g. be configured to lower an activation temperature and / or activation pressure for decomposition of the blowing agent.

[0156] Recycled foamed EVA copolymer article

[0157] In an eighth aspect, the present disclosure provides a recycled foamed EVA copolymer article comprising a crosslinked reaction product of the recycling foaming composition of any one of the embodiments described herein, in particular including but not limited to any of the embodiments described herein in the context of the sixth aspect of the present disclosure. Since the recycled foamed EVA copolymer article comprises a crosslinked reaction product of the recycling foaming composition, it is understood that the embodiments described herein in the context of the recycling foaming composition (including but not limited to embodiments described in the context of the sixth aspect of the present disclosure) also apply analogously to the recycled foamed EVA copolymer article, unless specifically stated otherwise or unless the context clearly dictates otherwise, with the exception that in the recycled foamed EVA copolymer article, the recycling foaming composition is in a crosslinked, foamed state.

[0158] Thus, the crosslinked reaction product of the recycling foaming composition typically comprises a crosslinked foamed reaction product comprising:

[0159] - a scrap foamed EVA copolymer product and

[0160] - a virgin foaming composition comprising: o a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups; o a metal ion; and o an EVA copolymer.

[0161] In a typical embodiment, at least the EVA copolymer in the crosslinked foamed reaction product is in a foamed and crosslinked state. Typically, in the crosslinked foamed reaction product, the first polymer is also in a foamed and crosslinked state. Typically, in the crosslinked foamed reaction product, the scrap foamed EVA copolymer product is also in a foamed and crosslinked state. In typical embodiments, the scrap foamed EVA copolymer product is in a foamed and crosslinked state. In some embodiments, the scrap foamed EVA copolymer product typically comprises a plurality of covalent crosslinks between copolymer chains of the EVA copolymer. For example, the covalent crosslinks may be formed by C-C bonds or C=C bonds, preferably C-C bonds.

[0162] Depending on the application, the recycled foamed EVA copolymer article may comprise different amounts of scrap foamed EVA copolymer product. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 3 wt.-%, preferably at least 6 wt.-%, more preferably 10 wt.-% or more, with respect to the total weight of the recycled foamed EVA copolymer article. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 10 wt.-%, such as at least 15 wt.-%, such as at least 20 wt.-%, particularly at least 25 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of up to 70 wt.-%, preferably up to 60 wt.-%, more preferably up to 50 wt.-%, such as up to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount from 3 wt.-% to 50 wt.-%, preferably from 5 wt.-% to 45 wt.-%, more preferably from 10 wt.-% to 35 wt- %, with respect to the total weight of the recycled foamed EVA copolymer article. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount from 15 wt.-% to 50 wt.-%, preferably from 20 wt- % to 40 wt.-%, more preferably from 25 wt.-% to 35 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article. In some embodiments, the recycled foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between the metal ions and the carboxylate groups of the first polymer. For example, in some embodiments, copolymer chains of the first polymer are crosslinked by the metal ions in the recycled foamed EVA copolymer article. This crosslinking may e.g. involve binding of the metal ions to the (meth)acrylate groups of the first polymer.

[0163] In some embodiments, the recycled foamed EVA copolymer article comprises a plurality of covalent crosslinks between copolymer chains of the EVA copolymer. For example, the covalent crosslinks may be formed by C-C bonds or C=C bonds, preferably by C-C bonds.

[0164] In some embodiments, the recycled foamed EVA copolymer article has a density of less than 0.40 g / cm3, preferably from 0.05 g / cm3to 0.30 g / cm3, more preferably from 0.15 g / cm3to 0.27 g / cm3, more preferably from 0.18 g / cm3to 0.25 g / cm3. In some embodiments, the recycled foamed EVA copolymer article has a density of up to 0.29 g / cm3, preferably up to 0.27 g / cm3, such as up to 0.26 g / cm3. In some embodiments, the recycled foamed EVA copolymer article has a density of at least 0.10 g / cm3, preferably at least 0.11 g / cm3, more preferably at least 0.12 g / cm3, more preferably at least 0.13 g / cm3.

[0165] The embodiments described in the previous paragraph may for example apply to embodiments in which the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 5 wt.-%, preferably from 5 wt.- % to 50 wt.-%, more preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article. Thus, for example, in some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 5 wt.-%, preferably from 5 wt.-% to 50 wt.-%, more preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article, and wherein the recycled foamed EVA copolymer article has a density of less than 0.40 g / cm3, preferably from 0.05 g / cm3to 0.40 g / cm3, more preferably from 0.15 g / cm3to 0.35 g / cm3. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount from 5 wt.-% to 50 wt.-%, preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article, and wherein the recycled foamed EVA copolymer article has a density from 0.10 g / cm3to 0.40 g / cm3, more preferably from 0.15 g / cm3to 0.30 g / cm3.

[0166] In some embodiments, the recycled foamed EVA copolymer article has a hardness (Asker C) from 35 to 60, preferably from 44 to 56, as determined according to ASTM D2240. In the recycled foamed EVA copolymer article has a hardness (Asker C) of at least 30, preferably at least 36, more preferably at least 41 , as determined according to ASTM D2240. In some embodiments, the recycled foamed EVA copolymer article has a hardness (Asker C) of up to 60, preferably up to 56, more preferably up to 54, as determined according to ASTM D2240.

[0167] The embodiments described in the previous paragraph may for example apply to embodiments in which the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 5 wt.-%, preferably from 5 wt.- % to 50 wt.-%, more preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article. Thus, for example, in some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 5 wt.-%, preferably from 5 wt.-% to 50 wt.-%, more preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article, and wherein the recycled foamed EVA copolymer article has a hardness (Asker C) from 35 to 60, preferably from 44 to 56, as determined according to ASTM D2240. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount from 5 wt.-% to 50 wt.-%, preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article, and wherein the recycled foamed EVA copolymer article has a hardness (Asker C) from 35 to 60, preferably from 44 to 56, as determined according to ASTM D2240.

[0168] In some embodiments, the recycled foamed EVA copolymer article has a compression set from 43% to 62%, as determined according to ASTM D 395-B. In some embodiments, the recycled foamed EVA copolymer article has a compression set of at least 43%, preferably at least 45%, more preferably at least 47%, as determined according to ASTM D 395-B. In some embodiments, the recycled foamed EVA copolymer article has a compression set of up to 68%, preferably up to 63%, more preferably up to 60%, as determined according to ASTM D 395-B.

[0169] In some embodiments, the recycled foamed EVA copolymer article has a compression strength from 0.15 MPa to 0.60 MPa, preferably from 0.20 MPa to 0.55 MPa, as determined at 50% strain. In some embodiments, the recycled foamed EVA copolymer article has a compression strength of at least 0.10 MPa, preferably at least 0.15 MPa, more preferably at least 0.20 MPa, as determined at 50% strain. In some embodiments, the recycled foamed EVA copolymer article has a compression strength of up to 0.70 MPa, preferably up to 0.62 MPa, more preferably up to 0.57 MPa, as determined at 50% strain. The compression strength, as used herein, is determined at 50% strain, as is described in the example section (see section “Foam Test Methods” below). In some embodiments, the foam is substantially closed cell. In other words, in some embodiments, the recycled foamed EVA copolymer article comprises substantially closed cell foam.

[0170] In some embodiments, the recycled foamed EVA copolymer article has a density that is no more than 60%, preferably no more than 30%, higher than the density of a foamed EVA copolymer article that is a foamed and crosslinked reaction product of a foaming composition that is substantially the same but without the scrap foamed EVA copolymer product.

[0171] The embodiments described in the previous paragraph may for example apply to embodiments in which the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 5 wt.-%, preferably from 5 wt.- % to 50 wt.-%, more preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article. Thus, for example, in some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 5 wt.-%, preferably from 5 wt.-% to 50 wt.-%, more preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article, and wherein the recycled foamed EVA copolymer article has a density that is no more than 60%, preferably no more than 30%, higher than the density of a foamed EVA copolymer article that is a foamed and crosslinked reaction product of a foaming composition that is substantially the same but without the scrap foamed EVA copolymer product. In some embodiments, the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount from 5 wt.-% to 50 wt.-%, preferably from 10 wt.-% to 40 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article, and wherein the recycled foamed EVA copolymer article has a density that is no more than 60%, preferably no more than 30%, higher than the density of a foamed EVA copolymer article that is a foamed and crosslinked reaction product of a foaming composition that is substantially the same but without the scrap foamed EVA copolymer product.

[0172] In some embodiments, the recycled foamed EVA copolymer article has a compression set that is smaller than the compression set of a foamed EVA copolymer article that is a foamed and crosslinked reaction product of a foaming composition that is substantially the same but without the scrap foamed EVA copolymer product.

[0173] In some embodiments, the recycled foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole.

[0174] Depending on the application, the recycled foamed EVA copolymer article may comprise further components, e.g. additives. In some embodiments, the recycled foamed EVA copolymer article consists of the crosslinked reaction product of the recycling foaming composition.

[0175] Depending on the application, the recycled foamed EVA copolymer article can be made using different methods. In some embodiments, the recycled foamed EVA copolymer article is made using the method of making a recycled foamed EVA copolymer article described herein, in particular including but not limited to embodiments described herein in the context of the seventh aspect of the disclosure.

[0176] Uses

[0177] In a ninth aspect, the present disclosure provides a use of EMAA copolymer or ionomer or of EAA or ionomer or of a mixture thereof in a foaming composition for enhancing the recyclability of a foamed EVA copolymer article formed from the foaming composition. The foaming composition comprises an EVA copolymer and a metal ion, preferably a zinc ion. Preferably, the foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole.

[0178] In some embodiments, the use relates to a use of EMAA copolymer or ionomer, preferably of EMAA copolymer.

[0179] In a further aspect, the present disclosure provides a use of the virgin foaming composition described herein for enhancing the recyclability of a foamed EVA copolymer article, in particular for enhancing the recyclability of a foamed EVA copolymer article formed from the virgin foaming composition. The virgin foaming composition used may be the virgin foaming composition according to any of the embodiments described herein, in particular including but not limited to any of the embodiment described in the context of the first aspect of the present disclosure. Preferably, the foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole.

[0180] In yet a further aspect, the present disclosure provides a use of the recycling foaming composition described herein for enhancing the recyclability of a foamed EVA copolymer article, in particular for enhancing the recyclability of a foamed EVA copolymer article formed from the recycling foaming composition. The recycling foaming composition used may be the recycling foaming composition according to any of the embodiments described herein, in particular including but not limited to any of the embodiment described in the context of the sixth aspect of the present disclosure. Preferably, the foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole. Exemplary Items of the Disclosure

[0181] Several embodiments, embodiments and aspects are described herein. Selected nonlimiting examples of the present disclosure are summarized in the following numbered list:

[0182] E 1 . Example relates to a virgin foaming composition for making a virgin foamed ethylene vinyl acetate copolymer article, the composition comprising: a) a first polymer comprising a plurality of carboxylic acid groups and / or carboxylate groups, wherein the first polymer is selected from:

[0183] - an ethylene methacryclic acid (EMAA) copolymer or ionomer;

[0184] - or an ethylene acrylic acid (EAA) copolymer or ionomer;

[0185] - or a mixture thereof; b) an EVA copolymer; c) a metal ion.

[0186] E 2. Example relates to the virgin foaming composition according to example 1 , wherein the EMAA copolymer or ionomer, respectively, or the EAA copolymer or ionomer, comprises from 5 wt.-% to 40 wt.-%, preferably from 5 wt.-% to 25 wt.-%, more preferably from 10 wt.-% to 20 wt.-%, more preferably 15 wt.-%, combined methacrylic acid and methacrylate, respectively, or combined acrylic acid and acrylate.

[0187] E 3. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the virgin foaming composition comprises the first polymer in an amount of at least 1 wt.-%, preferably at least 3 wt.-%, more preferably from 3 wt.-% to 20 wt.-%, even more preferably from 4 wt.-% to 10 wt.-%, with respect to the weight of EVA copolymer.

[0188] E 4. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the virgin foaming composition comprises a radical crosslinking agent in an amount of less than 1 wt.-%, preferably from 0.05 wt.-% to 0.70 wt.-%, more preferably from 0.10 wt.-% to 0.5 wt.-%, even more preferably from 0.15 wt.-% to 0.40 wt.-%, with respect to the weight of EVA copolymer

[0189] E 5. Example relates to the virgin foaming composition according to any one of the previous examples, wherein radical crosslinking agent is a peroxide, preferably an organic peroxide, more preferably bis(tert-butylperoxyisopropyl)benzene (BIPB) or dicumyl peroxide, more preferably BIPB.

[0190] E 6. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the metal ion is selected from one or more of the following: zinc ion, sodium ion, and magnesium ion, preferably zinc ion.

[0191] E 7. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the virgin foaming composition comprises the metal ion in the form of zinc oxide or zinc stearate, preferably zinc oxide.

[0192] E 8. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the virgin foaming composition comprises the EVA copolymer in an amount of at least 50 wt.-%, preferably at least 70 wt.-%, more preferably from 75 wt.-% to 97 wt.-%, even more preferably from 78 wt.-% to 95 wt.-%, with respect to the total weight of the virgin foaming composition. E 9. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the virgin foaming composition further comprises a blowing agent, preferably comprising a diazocarbamide, preferably azodicarbonamide.

[0193] E 10. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the virgin foaming composition is essentially free of compatibilizers, in particular essentially free of a hydrocarbon resin compatibilizer or a hydrogenated petroleum resin compatibilizer.

[0194] E 11. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the virgin foaming composition further comprises an activator comprising the metal ion.

[0195] E 12. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the EVA copolymer comprises from 10 wt.-% to 70 wt.-%, preferably from 10 wt.-% to 50 wt.-%, more preferably from 15 wt.-% to 40 wt.-%, more preferably from 20 wt.-% to 35 wt.-%, more preferably from 25 wt.-% to 31 wt.-%, vinyl acetate.

[0196] E 13. Example relates to the virgin foaming composition according to any one of the previous examples, wherein the first polymer is an ionomer.

[0197] E 14. Example relates to the virgin foaming composition according to example 13, wherein in the ionomer, the metal ion is a counterion to the carboxylate groups.

[0198] E 15. Example relates to a method of making a virgin foamed EVA copolymer article, the method comprising the steps of: a) providing the virgin foaming composition according to any one of the previous examples; b) heating and / or compressing the provided virgin foaming composition to a temperature and / or pressure sufficient to obtain crosslinking of the virgin foaming composition c) forming the crosslinked composition into an article, thereby obtaining the virgin foamed EVA copolymer article.

[0199] E 16. Example relates to the method according to example 15, wherein the virgin foaming composition comprises a / the blowing agent and the virgin foaming composition is heated and / or compressed to a temperature and / or pressure sufficient to activate the blowing agent to obtain foaming.

[0200] E 17. Example relates to the method according to any one of examples 15-16, wherein in step b) the virgin foaming composition is compression molded or injection molded.

[0201] E 18. Example relates to the method according to example 17, wherein in step b) the virgin foaming composition is compression molded and a mold is filled to a mold fill factor from 80 vol.-% to 95 vol.-%, preferably from 85 vol.-% to 93 vol.-%, more preferably 90 vol.-%, with respect to a total volume of the mold.

[0202] E 19. Example relates to the method according to any one of examples 15-18, wherein in step b) the virgin foaming composition is heated at a temperature of at least 100 °C, preferably at least 150 °C, more preferably from 150 °C to 220 °C.

[0203] E 20. Example relates to the method according to any one of examples 15-19, wherein in step b) the virgin foaming composition is compression molded at a compression force of at least 10 kN, preferably at least 25 kN, more preferably from 35 kN to 65 kN. E 21. Example relates to the method according to any one of examples 15-20, wherein the crosslinks obtained in step b) include a plurality of ionic crosslinks formed by ionic bonds between the metal ions and the carboxylate groups of the first polymer.

[0204] E 22. Example relates to the method according to any one of examples 15-21 , wherein the crosslinks obtained in step b) further include covalent crosslinks between copolymer chains of the EVA copolymer.

[0205] E 23. Example relates to a virgin foamed EVA copolymer article comprising a crosslinked reaction product of the virgin foaming composition of any one of examples 1-14.

[0206] E 24. Example relates to the virgin foamed EVA copolymer article according to example

[0207] 23, wherein the virgin foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between the metal ions and the carboxylate groups of the first polymer.

[0208] E 25. Example relates to the virgin foamed EVA copolymer article according to example

[0209] 24, wherein the plurality of ionic crosslinks are formed by ionic bonds between zinc ions and the carboxylate groups of the first polymer.

[0210] E 26. Example relates to the virgin foamed EVA copolymer article according to any one of examples 23-25, wherein the virgin foamed EVA copolymer article comprises a plurality of covalent crosslinks between copolymer chains of the EVA copolymer.

[0211] E 27. Example relates to the virgin foamed EVA copolymer article according to any one of examples 23-26, wherein the virgin foamed EVA copolymer article has a density of less than 0.50 g / cm3, preferably less than 0.40 g / cm3, more preferably from 0.05 g / cm3to 0.30 g / cm3, more preferably from 0.15 g / cm3to 0.27 g / cm3, more preferably from 0.15 g / cm3to 0.23 g / cm3. E 28. Example relates to the virgin foamed EVA copolymer article according to any one of examples 23-27, wherein the virgin foamed EVA copolymer article has a hardness (Asker C) from 30 to 60, preferably from 40 to 52, as determined according to ASTM D2240.

[0212] E 29. Example relates to the virgin foamed EVA copolymer article according to any one of examples 23-28, wherein the virgin foamed EVA copolymer article has a compression set from 45% to 65%, as determined according to ASTM D 395-B.

[0213] E 30. Example relates to the virgin foamed EVA copolymer article according to any one of examples 23-29, wherein the virgin foamed EVA copolymer article has a compression strength from 0.15 MPa to 0.30 MPa, preferably from 0.20 MPa to 0.25 MPa, as determined at 50% strain.

[0214] E 31. Example relates to the virgin foamed EVA copolymer article according to any one of examples 23-30, wherein the foam is substantially closed cell.

[0215] E 32. Example relates to the virgin foamed EVA copolymer article according to any one of examples 23-31 , wherein the virgin foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole.

[0216] E 33. Example relates to a recyclate for making a recycled foamed EVA copolymer article, wherein the recyclate comprises the virgin foamed EVA copolymer article according to any one of examples 23-32.

[0217] E 34. Example relates to the recyclate according to example 33, wherein the virgin foamed EVA copolymer is present in the recyclate in the form of a powder, pellets, granules or flakes, wherein preferably the powder, pellets, granules or flakes have a particle size not exceeding 5 mm, preferably not exceeding 2 mm. E 35. Example relates to the use of the recyclate according to any one of examples 33- 34 for making a recycled foamed EVA copolymer article.

[0218] E 36. Example relates to a recycling foaming composition for making a recycled foamed EVA copolymer article, wherein the recycling foaming composition comprises: a) a scrap foamed EVA copolymer product and b) a virgin foaming composition comprising:

[0219] - a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups;

[0220] - a metal ion; and

[0221] - an EVA copolymer.

[0222] E 37. Example relates to the recycling foaming composition according to example 36, wherein the scrap foamed EVA copolymer product is in a foamed and crosslinked state.

[0223] E 38. Example relates to the recycling foaming composition according to any one of examples 36-37, wherein the recycling foaming composition comprises the scrap foamed EVA copolymer product in an amount of at least 3 wt.-%, preferably at least 6 wt.-%, more preferably 10 wt.-% or more, with respect to the total weight of the recycling foaming composition.

[0224] E 39. Example relates to the recycling foaming composition according to any one of examples 36-38, wherein the recycling foaming composition comprises the scrap foamed EVA copolymer product in an amount from 3 wt.-% to 50 wt.-%, preferably from 5 wt.-% to 45 wt.-%, more preferably from 10 wt.-% to 35 wt.-%, with respect to the total weight of the recycling foaming composition.

[0225] E 40. Example relates to the recycling foaming composition according to any one of examples 36-39, wherein the first polymer is a first copolymer formed from at least a first monomer and a second monomer, wherein the second monomer comprises a carboxylic acid group and / or a carboxylate group.

[0226] E 41. Example relates to the recycling foaming composition according to example 40, wherein the first copolymer is a block copolymer, an alternating copolymer, a random copolymer or a graft copolymer.

[0227] E 42. Example relates to the recycling foaming composition according to any one of examples 40-41 , wherein the first monomer is hydrophobic.

[0228] E 43. Example relates to the recycling foaming composition according to any one of examples 40-42, wherein the first monomer is ethylene, propylene or styrene, preferably ethylene.

[0229] E 44. Example relates to the recycling foaming composition according to any one of examples 36-43, wherein the first polymer is an ionomer.

[0230] E 45. Example relates to the recycling foaming composition according to any one of examples 36-44, wherein in the ionomer, the metal ion is a counterion to the carboxylate groups.

[0231] E 46. Example relates to the recycling foaming composition according to any one of examples 36-45, wherein the virgin foaming composition is the virgin foaming composition according to any one of examples 1-14. E 47. Example relates to the recycling foaming composition according to any one of examples 36-46, wherein the scrap foamed EVA copolymer product comprises or consists of the recyclate according to any one of examples 33-35.

[0232] E 48. Example relates to the recycling foaming composition according to any one of examples 36-47, wherein the recycling foaming composition is essentially free of compatibilizers, in particular free of a hydrocarbon resin compatibilizer or a hydrogenated petroleum resin compatibilizer.

[0233] E 49. Example relates to a method of making a recycled foamed EVA copolymer article from the recycling foaming composition of any one of examples 36-48, the method comprising foaming the virgin foaming composition in the presence of the scrap foamed EVA copolymer product.

[0234] E 50. Example relates to the method according to example 49, wherein the method comprises the steps of : a) providing the recycling foaming composition of any one of examples 36-48; b) heating and / or compressing the provided recycling foaming composition to a temperature and / or pressure sufficient to obtain crosslinking; c) forming the crosslinked composition into an article, thereby obtaining the recycled foamed EVA copolymer article.

[0235] E 51. Example relates to the method according to example 50, wherein the recycling foaming composition comprises a / the blowing agent and the recycling foaming composition is heated and / or compressed to a temperature and / or pressure sufficient to activate the blowing agent to obtain foaming. E 52. Example relates to the method according to any one of examples 50-51 , wherein in step b) the recycling foaming composition is compression molded or injection molded.

[0236] E 53. Example relates to the method according to example 52, wherein in step b) the recycling foaming composition is compression molded and a mold is filled to a mold fill factor from 80 vol.-% to 95 vol.-%, preferably from 85 vol.-% to 93 vol.-%, more preferably 90 vol.-%, with respect to a total volume of the mold.

[0237] E 54. Example relates to the method according to any one of examples 50-53, wherein in step b) the recycling foaming composition is heated at a temperature of at least 100 °C, preferably at least 150 °C, more preferably from 150 °C to 220 °C.

[0238] E 55. Example relates to the method according to any one of examples 50-54, wherein in step b) the recycling foaming composition is compression molded at a compression force of at least 10 kN, preferably at least 25 kN, more preferably from 35 kN to 65 kN.

[0239] E 56. Example relates to the method according to any one of examples 50-55, wherein the crosslinks obtained in step b) include a plurality of ionic crosslinks formed by ionic bonds between the metal ions of the virgin foaming composition and the carboxylate groups of the first polymer of the virgin foaming composition.

[0240] E 57. Example relates to the method according to any one of examples 50-56, wherein the crosslinks obtained in step b) further include covalent crosslinks between copolymer chains of the EVA copolymer of the virgin foaming composition.

[0241] E 58. Example relates to a recycled foamed EVA copolymer article comprising a crosslinked reaction product of the recycling foaming composition of any one of examples 36- 49. E 59. Example relates to the recycled foamed EVA copolymer article according to example 58, wherein the scrap foamed EVA copolymer product is in a foamed and crosslinked state.

[0242] E 60. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-59, wherein the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 3 wt.-%, preferably at least 6 wt.-%, more preferably 10 wt.-% or more, with respect to the total weight of the recycled foamed EVA copolymer article.

[0243] E 61. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-60, wherein the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount from 3 wt.-% to 50 wt.-%, preferably from 5 wt.-% to 45 wt.-%, more preferably from 10 wt.-% to 35 wt.-%, with respect to the total weight of the recycled foamed EVA copolymer article.

[0244] E 62. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-61 , wherein the recycled foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between metal ions, preferably the metal ions of the virgin foaming composition, and carboxylate groups, preferably the carboxylate groups of the first polymer.

[0245] E 63. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-62, wherein the recycled foamed EVA copolymer article comprises a plurality of covalent crosslinks between copolymer chains of the EVA copolymer of the virgin foaming composition. E 64. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-63, wherein the recycled foamed EVA copolymer article has a density of less than 0.40 g / cm3, preferably from 0.05 g / cm3to 0.30 g / cm3, more preferably from 0.15 g / cm3to 0.27 g / cm3, more preferably from 0.18 g / cm3to 0.25 g / cm3.

[0246] E 65. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-64, wherein the recycled foamed EVA copolymer article has a hardness (Asker C) from 35 to 60, preferably from 44 to 56, as determined according to ASTM D2240.

[0247] E 66. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-65, wherein the recycled foamed EVA copolymer article has a compression set from 43% to 62%, as determined according to ASTM D 395-B.

[0248] E 67. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-66, wherein the recycled foamed EVA copolymer article has a compression strength from 0.15 MPa to 0.60 MPa, preferably from 0.20 MPa to 0.55 MPa, as determined at 50% strain.

[0249] E 68. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-67, wherein the recycled foamed EVA copolymer article comprises substantially closed cell foam.

[0250] E 69. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-68, wherein the recycled foamed EVA copolymer article has a density that is no more than 60%, preferably no more than 30%, higher than the density of a foamed EVA copolymer article that is a foamed and crosslinked reaction product of a foaming composition that is substantially the same but without the scrap foamed EVA copolymer product. E 70. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-69, wherein the recycled foamed EVA copolymer article has a compression set that is smaller than the compression set of a foamed EVA copolymer article that is a foamed and crosslinked reaction product of a foaming composition that is sub- stantially the same but without the scrap foamed EVA copolymer product.

[0251] E 71. Example relates to the recycled foamed EVA copolymer article according to any one of examples 58-70, wherein the recycled foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole.

[0252] E 72. Example relates to the use of EMAA copolymer or ionomer or of EAA or ionomer or of a mixture thereof in a foaming composition for enhancing the recyclability of a foamed EVA copolymer article formed from the foaming composition, wherein the foaming composition comprises an EVA copolymer and a metal ion, preferably a zinc ion.

[0253] EXAMPLES

[0254] Abbreviations and Materials In the examples below, the following materials as defined in Table 1 were used.

[0255] Table 1

[0256] The1H NMR spectrum of EVA was recorded on a Bruker DPX-400 spectrometer in deuterated chloroform. The result is given in Figure 1a. Integration of the peaks confirms that the EVA is approximately 28 wt% vinyl acetate. No impurities were detected. The peak assignment is as follows:1H NMR (chloroform-cb, 400 MHz) (ppm): -0.88 (s, -CH3), -1.25 (s, -CH2-), -1.50 (s, -CO-CH3), -2.03 (s, -CH2-CH-), -4.85 (s, -CH2-CH-). Figure 1b shows the size exclusion chromatography (SEC) trace of EVA, which was recorded with a chloroform eluent. A symmetrical peak with a number average molecular weight (Mn) of 90,000 g / mol and a polydispersity index (£>) of 2.81 was obtained. The melt flow properties of EVA were measured on a Ray Ran Model 6 Advanced Melt Flow System. The EVA was determined to have a melt flow index (MFI) of 3.376 ± 0.056 g / 10 min (190 °C / 2.16 kg).

[0257] A good solvent to solubilize EMAA could not be found, so its1H NMR spectrum and SEC trace were not obtained. However, it was determined to have an MFI of 27.117 ± 2.429 g / 10 min (190 °C / 2.16 kg). This MFI value will decrease substantially as the EMAA forms a salt with zinc in the foam compounds, most likely closer to the zinc ionomer Surlyn 9320, which was measured to have an MFI value of 2.263 g / 10 min (190 °C / 2.16 kg).

[0258] Foam Preparation

[0259] Mixing was performed on a Brabender 350SX measuring mixer with intermeshing blades fitted with a pneumatic loading chute. The mixer has a bowl volume of 318 cm3and was filled to 70% v / v for mixing each compound. An initial temperature of 90 °C was set, and all ingredients in the formulation were added at 0 mins. Mixing proceeded at 30 rpm for 8 mins, ensuring the internal temperature remained below 110 °C. The compound was then rolled to a sheet using a Servitec Polymix 110 L two-roll mill set at 70 °C and placed in a drying oven at 60 °C for at least 12 hours.

[0260] A 110 mm x no mm x 7 mm steel mold was sprayed with Ambersil DH-SIL release agent and filled with compound to 90% of its volume. The mold was first placed in a hot press for 600 seconds at 100 °C and 50 kN to ensure even compound distribution. Finally, compounds were compression molded at 173 °C for 600 seconds and 50 kN to produce the final foam.

[0261] To produce recyclate, cured foams were cut into approximately 5 mm x 5 mm squares and then cryomilled in batches using a Spex SamplePrep 6870 Freezer / Mill for 3 x 10 mins per batch. After cryomilling, each batch was passed through a medium-mesh sieve (1 .5 mm x 1 .5 mm pore size). Foam parts too large to pass through the sieve were added to the next batch for cryomilling.

[0262] Foam Test Methods

[0263] Before all test methods, foams were placed in a Binder M KF 56 Dynamic Climate Chamber set at 23 °C and 50% relative humidity for at least 24 hours.

[0264] Asker C Hardness, as used herein, was measured with a Montech HT 3000 durometer following ASTM D2240 (version of 2004). Data is reported as the average and standard deviation of five collection points.

[0265] Shrinkage was evaluated over 24 hours at 70 °C, according to Satra TM70. Following ISO 1183-1 :2019, foam density, as used herein, was measured using immersion on a Mettler Toledo Analytical Balance ME204 with a density kit. The data is given as the average and standard deviation of three specimens.

[0266] Compression set, as used herein, was measured with a Montech CS 3000 apparatus with 4.8 mm spacers, following ASTM D 395-B (preferably the version of 2018). The data are presented as the average and standard deviation of three specimens per sample.

[0267] Compression stress-strain curves were measured on a Shimadzu AGS-X tensile tester at a strain rate of 5 mm / min. The stress value at 50% strain as used herein is defined as the Compression Strength. This value is presented as the average and standard deviation of three specimens per sample. Representative stress-strain plots are also given.

[0268] The compression strength at 50% strain is generally determined as defined herein. Optionally, in some variants, standard ASTM D3575 (2014) may be used as an auxiliary resource to the definition of compression strength provided herein, wherein any specific definitions for determining compression strength specifically provided in the present disclosure prevail.

[0269] Example 1

[0270] Example 1a is a representative standard EVA foam composition used as a control. Examples 1 b to 1d are EVA foam compositions that show the effect of increasing amounts of recyclate in a standard EVA formulation on foam properties.

[0271] Table 2 provides the formulations used, with numerical values referring to parts per hundred rubber (phr). It also provides the curing conditions used and the resulting foam properties. Table 2 Example 2

[0272] Examples 2a to 2d are EVA foam compositions that show the effect of reducing the amount of peroxide and adding 5 phr of EMAA copolymer on mechanical properties and recyclability. Table 3 details the formulations used, the foaming conditions, and the foam properties.

[0273] Table 3

[0274] Example 3

[0275] Examples 3a to 3d show the effect of increasing the amount of EMAA added to 10 phr in EVA foam compositions with 0.3 phr of BIPB. Table 4 shows the formulations used, in addition to their curing conditions and properties after foaming.

[0276] Table 4

[0277] Discussion

[0278] Example 1a is a representative standard EVA foam formulation. Examples 1b, 1c and

[0279] 1d are the same formulation with ground Example 1a added at 10 wt%, 20 wt% and 30 wt%, respectively.

[0280] As shown in Figure 2, the Asker C hardness of the foams increases following the addition of 10 wt% and 20 wt% of recyclate, from 56.50 ± 0.45 to 59.72 ± 2.24 and 66.52 ± 4.33, respectively. Further addition of recyclate to 30 wt% appears to decrease Asker C hardness to 54.86 ± 3.34 (example 1d). However, without wishing to be bound to a the- ory, this is believed to be a result of the highly inhomogeneous surface of these samples, which made accurate penetration of the durometer’s indenter challenging. Comparative photographs of Example 1a and 1d in Figure 10 show the poor foam structure formed in Example 1d.

[0281] Figure 3 shows the trend in the density values of Example 1 was similar. Here, the initial density of 0.309 ± 0.004 g / cm3increases markedly to 0.560 ± 0.049 g / cm3and 0.760 ± 0.024 g / cm3in Examples 1 b and 1c, respectively. This demonstrates the poor expansion of these foams when recyclate is added. In Example 1 d, the density of the material drops to 0.538 ± 3.34 g / cm3due to the foam's highly discontinuous structure with 30 wt% of recyclate.

[0282] Figure 2 shows that reducing the amount of peroxide and substituting 5 phr of EVA with EMAA lowers the Asker C hardness of the foam to 47.16 ± 1.15 (Example 2a). Substituting 10 phr of EVA to EMAA further reduces the Asker C hardness to 44.14 ± 1.88 (Example 3a). In both cases, lowering the density of permanent crosslinks allows for greater chain mobility, making the foam more deformable during indentation and reducing the hardness value. The difference in hardness value between Example 2a and Example 3a may relate to the density of the foams, where higher amounts of EMAA increase expansion and lower foam density, as shown in Figure 3. Addition of recyclate to Examples 2 and 3 results in slightly increased hardness and density. Figures 2 and 3 show this is marginally more prominent in Example 2. A contributing factor may be that when adding recyclate partially crosslinked with peroxide, even though the polymer chains have improved flowability, the polymers' overall molecular weight and molecular weight distribution will be altered. These factors affect foam expansion and, therefore, density and hardness. However, in both Example 2 and 3, the hardness and density of the foams with 30 wt% recyclate are in a range which for many industrial applications is considered acceptable. Figure 4 shows that for Example 1 , the foams follow a trend of decreasing shrinkage with increasing amounts of recyclate in the formulation. Without withing to be bound to a theory, this is again believed to be due to their higher density, where the thicker cell walls create a more rigid network. The opposite trend was observed in Examples 2 and 3, where higher amounts of recyclate increased shrinkage in the foams. This may be due to the polymer from the added recyclate not fully diffusing through the virgin polymer in each sample during the compounding and curing processes and then rearranging during the shrinkage evaluation at 70 °C for 24 hours, resulting in increased contraction. Interestingly, Fig. 4 shows a significantly lower shrinkage value of Example 3a. Without wishing to be bound to a theory, this could be attributed to the stabilizing effect of having a large number of ionic bonds in the system.

[0283] Figure 5 shows the compression set data of Examples 1 , 2, and 3. The compression set of the control Example 1a is low, at 38.78 ± 0.32%. Adding 10 to 30 wt% of recyclate to Example 1 dramatically increases its compression set to 66-72%. This could be the result of the poorly formed cells in these foams, which have a larger and more irregular structure and are less able to recover after deformation. Example 2a and Example 3a have high compression set values of 60.34 ± 1.84% and 61.21 ± 1.16%, respectively.

[0284] The compression stress of Examples 1 to 3 under an applied strain was evaluated on a universal tester. To compare between examples, the stress value at a 50% strain was selected and defined as the Compression Strength of the sample. These results are given in Figure 6. Example 1a has a Compression Strength of 0.63 ± 0.01 MPa, which increases dramatically with the addition of 10 wt% recyclate, with Example 1 b having a Compression Strength of 1.77 ± 0.58 MPa. Example 1c had a Compression Strength of 3.90 ± 0.82 MPa, indicating that with 20 wt% recyclate the foam had become even more resistant to compression. The Compression Strength of Example 1d drops to 1 .53 ± 0.34 MPa, resulting from the particularly poor structure of this material, as shown in the photographs in Figure 10. The larger error in the measurements of Examples 1 b to 1d also highlights the inhomogeneity of these samples, with all three deviating significantly in both the average and standard deviation values of their Compression Strength, compared with the original sample, Example 1a.

[0285] The Compression Strength of Examples 2a and 3a is lower than that of Example 1a, at 0.24 ± 0.01 MPa and 0.21 ± 0.01 MPa, respectively. Without wishing to be bound to a theory, their lower density could be a major contributing factor to this. With the addition of recyclate to Example 2, there is a slight increase in Compression Strength, with values going from 0.30 ± 0.01 MPa to 0.54 ± 0.03 MPa. This is consistent with the above data showing that with 5 phr of EMAA, Example 2 is less able to recover foam density with the same amount of AC3000 blowing agent in the formulation. This effect is decreased in Example 3, where with the addition of recyclate, the Compression Strength values marginally increase from 0.22 ± 0.02 MPa with 10 wt% recyclate to 0.31 ± 0.01 MPa with 30 wt% recyclate. In both Examples 2 and 3, the low error on the Compression Strength data shows the consistency of the foam structure in these samples.

[0286] Representative full compression stress-strain curves of Examples 1 to 3 are given in Figures 7 to 9. Example 1a in Figure 7 shows the typical stress-strain behavior of foam under compression, with an elastic region up to around 15% strain where the stress linearly increases with strain. Then, a yield point transitions to a crushing region, where the foam’s cells collapse and the stress response plateaus. At approximately 55% strain, the foam undergoes densification, where the collapsed foam packs tightly, and the stress increases rapidly with applied strain. After the addition of recyclate in Example 1 , this behavior changes dramatically. In all cases, the foams quickly transition to the densification phase, with little evidence of a crushing region. This is particularly prominent in Example 1c. These examples again show the poor foam formation when adding recy- clate to a standard EVA foam.

[0287] Figures 8 and 9 show that Examples 2a and 3a exhibit the same typical stress response to compressive strain as Example 1a. However, the elastic region is shorter in both cases, up to approximately 10%. Their crushing regions are also slightly extended to approximately 65% before undergoing densification. These results may be due to the lower density of foams with added EMAA. Again, some differences between Examples 2 and 3 with the addition of recyclate can be seen. In Example 2, the addition of recyclate slightly extends the elastic region of the stress-strain curves and causes a faster onset of the densification region, as shown in Figure 8. This is consistent with previous observations that with this amount of added EMAA, the foams with higher amounts of recyclate are denser and less able to recover the properties of the original sample. These effects were not observed in the stress-strain curves of Example 3, which are given in Figure 9. Here, a marginally faster onset of densification at 30 wt% recyclate (Example 3d) can be observed, but all curves are highly consistent with the original sample, Example 3a. These results show that substituting 10 phr of EVA with EMAA in the formulation and lowering the amount of added peroxide greatly enhances the recyclability of EVA foams.

[0288] Figures 10 to 12 show photographs of samples with 0 wt% and 30 wt% recyclate in Examples 1 to 3 to illustrate the differences in the foams' macroscopic structure. As mentioned above, the addition of 30 wt% recyclate to Example 1 results in extremely poor foam formation, with large, inhomogeneous and irregular pores. Conversely, in Examples 2 and 3, the macroscopic structure of the foams with 30 wt% recyclate is consistent with the original samples with 0 wt% recyclate, as shown in Figures 11 and 12.

Claims

AMENDED CLAIMS received by the International Bureau on 28 January 2026 (28.01.2026)PATENT CLAIMS1 . A recycling foaming composition for making a recycled foamed EVA copolymer article, wherein the recycling foaming composition comprises: a. a scrap foamed EVA copolymer product and b. a virgin foaming composition comprising: i. a first polymer comprising a plurality of carboxylic acid groups and / or a plurality of carboxylate groups; ii. a metal ion; and iii. an ethylene vinyl acetate (EVA) copolymer.

2. The recycling foaming composition according to claim 1 , wherein the first polymer comprised in the virgin foaming composition is selected from: i. an ethylene methacryclic acid (EMAA) copolymer or ionomer; ii. or an ethylene acrylic acid (EAA) copolymer or ionomer; iii. or a mixture thereof. and wherein optionally:75 the virgin foaming composition comprises a radical crosslinking agent in an amount of less than 1 wt.-%, preferably from 0.05 wt.-% to 0.70 wt.-%, more preferably from 0.10 wt.-% to 0.5 wt.-%, even more preferably from 0.15 wt.-% to 0.40 wt.-%, with respect to the weight of EVA copolymer in the virgin foaming composition; and / or the virgin foaming composition comprises the first polymer in an amount of at least 1 wt.-%, preferably at least 3 wt.-%, more preferably from 3 wt.- % to 20 wt.-%, even more preferably from 4 wt.-% to 10 wt.-%, with respect to the weight of EVA copolymer in the virgin foaming composition; and / or the metal ion in the virgin foaming composition is selected from one or more of the following: zinc ion, sodium ion, and magnesium ion, preferably zinc ion.

3. The recycling foaming composition according to any one of claims 1 -2, wherein the recycling foaming composition comprises the scrap foamed EVA copolymer product in an amount of at least 3 wt.-%, preferably at least 6 wt.-%, more preferably 10 wt.-% or more, with respect to the total weight of the recycling foaming composition.

4. The recycling foaming composition according to any one of claims 1 -3, wherein the scrap foamed EVA copolymer product comprises or consists of a virgin foamed EVA copolymer article which comprises a foamed and crosslinked reaction product of a further virgin foaming composition comprising:a. a further first polymer comprising a plurality of carboxylic acid groups and / or carboxylate groups, wherein the further first polymer is selected from: i. an ethylene methacryclic acid (EMAA) copolymer or ionomer; ii. or an ethylene acrylic acid (EAA) copolymer or ionomer; iii. or a mixture thereof; b. an ethylene vinyl acetate (EVA) copolymer; c. a metal ion. wherein optionally: the virgin foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between the metal ions, preferably zinc ions, and the carboxylate groups of the further first polymer; and / or the virgin foamed EVA copolymer article has a density of less than 0.50 g / cm3, preferably less than 0.40 g / cm3, more preferably from 0.05 g / cm3to 0.30 g / cm3, more preferably from 0.15 g / cm3to 0.27 g / cm3, more preferably from 0.15 g / cm3to 0.23 g / cm3; and / or the virgin foamed EVA copolymer article has a hardness (Asker C) from 30 to 60, preferably from 40 to 52, as determined according to ASTM D2240.

775. Method of making a recycled foamed EVA copolymer article from the recycling foaming composition of any one of claims 1 -4, the method comprising foaming the virgin foaming composition in the presence of the scrap foamed EVA copolymer product.

6. The method according to claim 5, wherein in step b) the recycling foaming composition is compression molded or injection molded, wherein optionally in step b) the recycling foaming composition is compression molded and a mold is filled to a mold fill factor from 80 vol.-% to 95 vol.-%, preferably from 85 vol.-% to 93 vol.-%, more preferably 90 vol.-%, with respect to a total volume of the mold.

7. A recycled foamed EVA copolymer article comprising a foamed and crosslinked reaction product of the recycling foaming composition of any one of claims 1 -4.

8. The recycled foamed EVA copolymer article according to claim 7, wherein the recycled foamed EVA copolymer article comprises the scrap foamed EVA copolymer product in an amount of at least 3 wt.-%, preferably at least 6 wt.-%, more preferably 10 wt.-% or more, with respect to the total weight of the recycled foamed EVA copolymer article.

9. The recycled foamed EVA copolymer article according to any one of claims 7-8, wherein the recycled foamed EVA copolymer article comprises a plurality of ionic crosslinks formed by ionic bonds between metal ions, preferably the metal ions of the virgin foaming composition, and carboxylate groups, preferably the carboxylate groups of the first polymer.

10. The recycled foamed EVA copolymer article according to any one of claims 7-9, wherein the recycled foamed EVA copolymer article has a density of less than780.40 g / cm3, preferably from 0.05 g / cm3to 0.30 g / cm3, more preferably from 0.15 g / cm3to 0.27 g / cm3, more preferably from 0.18 g / cm3to 0.25 g / cm3.1 1 . The recycled foamed EVA copolymer article according to any one of claims 7-10, wherein the recycled foamed EVA copolymer article has a hardness (Asker C) from 35 to 60, preferably from 44 to 56, as determined according to ASTM D2240.

12. The recycled foamed EVA copolymer article according to any one of claims 7-1 1 , wherein the recycled foamed EVA copolymer article has a compression set from 43% to 62%, as determined according to ASTM D 395-B.

13. The recycled foamed EVA copolymer article according to any one of claims 7-12, wherein the recycled foamed EVA copolymer article comprises substantially closed cell foam.

14. The recycled foamed EVA copolymer article according to any one of claims 7-13, wherein the recycled foamed EVA copolymer article has a density that is no more than 60%, preferably no more than 30%, higher than the density of a foamed EVA copolymer article that is a foamed and crosslinked reaction product of a foaming composition that is substantially the same but without the scrap foamed EVA copolymer product.

15. The recycled foamed EVA copolymer article according to any one of claims 7-14, wherein the recycled foamed EVA copolymer article is a sole for a shoe, preferably a midsole and / or an insole and / or an outsole.

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