Foamable composition and foam article produced therefrom

Abstract

A foaming composition comprising: (a) at least one elastomer selected from the group consisting of (i) an ethylene / alpha-olefin multi-block interpolymer, (ii) an ethylene / alpha-olefin elastomer, and (iii) combinations thereof; (b) at least one ethylene vinyl acetate; (c) at least one polarity modifier selected from the group consisting of (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) combinations thereof; (d) at least one crosslinking agent; and (e) at least one foaming agent.

Description

Technical Field

[0001] The present invention relates to a foamable composition for manufacturing a foam article and a foam article prepared using the foamable composition. For example, the foamable composition of the present invention can be used for manufacturing foam articles such as shoe parts.

Background Art

[0002] Polyolefin elastomers such as random ethylene-alpha-olefin copolymers and olefin block copolymers play an important role in footwear applications such as the insole of sports shoes, the sole, insole, or mono-block shoes (i.e., shoes made entirely of a single compound).

[0003] The aforementioned polyolefin elastomers are used in compositions or formulations containing ethylene vinyl acetate (EVA) to modify the EVA and improve many mechanical properties of the composition, such as elasticity, light weight, shrinkage, compression set, and hardness. The level of elastomer in the formulation used to manufacture shoe parts varies according to the shoe parts and the type of shoe. The level of elastomer in the formulation can vary, for example, from 10 phr to 90 phr. "High-value-added shoes" typically contain at least 50 phr of elastomer. However, the higher the level of elastomer (a non-polar material) used in the formulation for making shoe parts, the more difficult it becomes to bond the shoe parts to other parts of the shoe made of different materials such as polyvinyl chloride (PVC) (a polar material).

[0004] When attempting to bond non-polar foams made of EVA and elastomers (e.g., polyolefin elastomer (POE), and / or olefin block copolymer (OBC)) to other polar substrates such as PVC at an elastomer level of ≥ 50 phr, for example, problems with poor bond strength have been observed. This problem of poor bonding has been occurring for decades. In attempts to solve the problems so far, special primers have been used, particularly in Asia, for the purpose of improving the bond strength between non-polar and polar substrates. However, known primers are not always available in countries in Latin America such as Brazil, and when known primers are available, the primers can be very expensive. Therefore, it is necessary to develop a formulation in which a polar high-pressure copolymer (HPC) material is added to the formulation to increase the polarity of the compound. As a result, foam products produced using a formulation having a compound with increased polarity can have improved bonding performance even when using standard commercially available primers.

[0005] Many footwear manufacturers, such as shoe manufacturers, have no objection to adding more than 50 phr of elastomer to the shoe manufacturer's formulation due to the technical requirements of the shoe manufacturer. However, when a shoe manufacturer attempts to add more than 50 phr of elastomer to the shoe manufacturer's formulation, the shoe manufacturer's formulation exhibits poor bonding performance, so the shoe manufacturer avoids adding a higher level of elastomer to the shoe manufacturer's formulation. When it is desired that new footwear, such as a new shoe model, be introduced to the market by a shoe manufacturer, if the new shoe exhibits poor bonding in any of the parts that make up the new shoe, it may be impossible for the shoe manufacturer to bring such a new shoe model to the market.

[0006] Various methods have been tried to improve the bonding performance of EVA foams containing elastomers, but none have been successful. Such methods include, for example: (1) special primers applied to the foam as described above (NanPao in Asia is one supplier of such primers, but they are not available in Latin America); (2) ≧40 wt% VA (vinyl-acetate) in combination with EVA (ethylene vinyl acetate) to improve the polarity of the EVA compound and thus the bonding performance of the formulation; (3) additional steps for foam preparation such as sanding the surface of the foam before applying the primer to the surface of the foam; and (4) the use of special adhesives applied to the foam. However, the use of the methods described above still results in poor bonding performance of the formulation.

[0007] For example, Chinese Patent No. 1997693 (B) (equivalent to US Patent Application Publication No. 2005 / 0288442) discloses a composition comprising: (i) 50 wt% to 95 wt%, preferably 70 wt% to 90 wt% of an ethylene-acrylate copolymer; (ii) 5 wt% to 50 wt%, preferably 10 wt% to 30 wt% of an acid copolymer or ionomer or acid copolymer; and (iii) 0 wt% to 40 wt% of a soft ethylene polymer. The foam composition described in the above reference improves crosslinking and mechanical properties while retaining the inherent advantages of ethylene-methyl acrylate copolymers. However, the above reference does not disclose any improvement in the bonding performance of foam formulations containing ethylene-acrylate copolymers, acid copolymers or ionomers, and ethylene polymers. Also, while the above reference mentions the use of ethylene-methyl acrylate, the formulation does not include a combination of ethylene-methyl acrylate, EVA, and elastomers.

[0008] Other references disclose foam compositions, foam layers, and / or foam articles, such as International Publication No. WO 2017 / 156674 (A1), Indian Patent No. 202017000715 (A) (corresponding to International Publication No. WO 2019 / 000155 (A1)), and Chinese Patent No. 103304882 (A) (corresponding to International Publication No. WO 2013 / 134354). However, none of the references mentioned above disclose the use of a copolymer of ethylene and methyl (or butyl) acrylate to improve the polarity of the foam material, and / or a foaming composition containing a copolymer of ethylene and methyl (or butyl) acrylate in combination with EVA and at least 50 phr of an elastomer (POE and / or OBC) for the purpose of improving bonding performance.

[0009] Therefore, it would be desirable to provide a foaming composition comprising a copolymer of ethylene and methyl (or butyl) acrylate in combination with EVA and at least 50 phr of an elastomer (POE and / or OBC), wherein the foaming composition can be used to produce a foam article, and the foam article exhibits improved bonding performance. SUMMARY OF THE INVENTION

[0010] The foaming composition of the present invention solves the problem of poor bonding encountered by prior art formulations. The foaming formulation of the present invention comprises EVA, at least one elastomer (e.g., POE and / or OBC) at a concentration of at least 50 phr, and at least one copolymer of ethylene and acrylate, such as a copolymer of ethylene and methyl acrylate or a copolymer of ethylene and butyl acrylate, at a concentration level that can vary from 10 phr to 40 phr depending on all the constituents in the formulation. The foaming composition of the present invention can also include one or more other raw material constituents such as crosslinking agents, blowing agents, activators, and nucleating agents.

[0011] One general embodiment of the present invention is directed to a foaming composition comprising an HPC material added to a formulation containing EVA and an elastomer. For example, the HPC material can include an ethylene and methyl (or butyl) acrylate copolymer that can be added to a formulation of EVA and an elastomer. The elastomer can be present in the formulation at ≧50 phr. The addition of the HPC material improves the polarity of the resulting foam composition and results in improved bonding of the resulting foam to other substrates such as PVC.

[0012] Another general embodiment of the present invention is directed to a foaming composition or formulation for use in the production of a foam article, the foaming composition comprising: (a) (i) an ethylene / alpha-olefin multiblock interpolymer having a density of 0.850 g / cc to 0.890 g / cc in one general embodiment and a melt index (I2) of 0.5 g / 10 min to 50 g / 10 min in one general embodiment, (ii) an ethylene / alpha-olefin elastomer having a density of 0.850 g / cc to 0.890 g / cc in one general embodiment and an I2 of 0.5 g / 10 min to 50 g / 10 min in one general embodiment, and (iii) one or more elastomers selected from the group consisting of combinations thereof, wherein the concentration of the elastomer is ≧45 wt% based on the foaming composition, an elastomer; (b) at least one EVA, wherein the concentration of the EVA is ≧5 wt% based on the foaming composition, an EVA; (c) (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) one or more polarity modifiers selected from the group consisting of combinations thereof, wherein the concentration of the polarity modifier is in the range of 5 wt% to 50 wt% based on the foaming composition, a polarity modifier; (d) one or more crosslinking agents, wherein the concentration of the crosslinking agent is ≧1 wt% based on the foaming composition, a crosslinking agent; (e) one or more foaming agents, wherein the concentration of the foaming agent is ≧1 wt% based on the foaming composition, a foaming agent.

[0013] In yet another general embodiment, the present invention is directed to a foaming composition that advantageously includes the use of a curable primer that need not be UV cured.

[0014] In addition, the foaming composition of the present invention includes ≧50 phr of an elastomer without adversely affecting the bonding ability of a foam article made from the foaming composition when the foam article is bonded to another different material.

[0015] In yet another embodiment, the present invention is directed to a foam article such as a shoe part made from the above foaming composition.

[0016] In other embodiments, the present invention is directed to a process for preparing the above foaming composition and the above foam article.

[0017] The present invention is advantageous in that, by making a foam using the foaming composition of the present invention containing a copolymer of ethylene and acrylate (e.g., methyl acrylate or butyl acrylate) in a blend of EVA with at least 50 phr of an elastomer (POE and / or OBC), when bonding the foam to a polar substrate such as flexible PVC, the minimum bond strength required for satisfactory bonding performance of the foam is achieved while maintaining satisfactory results for the mechanical properties of the foam, such as density, shrinkage, resilience, and hardness. The present invention provides a foaming composition using at least 50 phr of an elastomer, such as an olefin block copolymer, and the resulting foaming composition can provide a foam article having improved bonding performance.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0019] Here, embodiments of the foaming composition and foam articles made from the foaming composition are referred to in detail. The foaming composition, in a broad embodiment, comprises (a) at least one elastomer, (b) at least one ethylene vinyl acetate, (c) at least one polarity modifier, (d) at least one crosslinking agent, and (e) at least one foaming agent. Optionally, other compounds such as accelerators and fillers can be added to the composition if desired.

[0020] The foam produced from the foaming composition may be used, for example, in footwear applications such as the manufacture of shoe parts. However, it should be noted that this application is merely an exemplary and illustrative implementation of the embodiments disclosed herein. The embodiments are applicable to other technologies that desire to bond the foam material to other different substrate materials while maintaining other mechanical properties of the foam material.

[0021] The term "composition" (used interchangeably herein with the term "formulation") refers to a mixture of materials including the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0022] The term "elastomer" refers to a polymer that has viscoelasticity (has both viscosity and elasticity), has very weak intermolecular forces compared to other materials, generally has a low Young's modulus, and a high failure strain. An elastomer has elastic properties, that is, an elastomer is a polymer that deforms under stress and returns to its original shape when the stress is removed, and has long flexible chain molecules with high mobility above its Tg (glass transition temperature).

[0023] As used herein, the term "polymer" refers to a polymer compound prepared by polymerizing monomers, whether of the same type or different types. Thus, the general term "polymer" includes (1) the term "homopolymer" (used to refer to a polymer prepared by polymerizing only one type of monomer, with the understanding that trace amounts of impurities may be incorporated into the polymer structure), and (2) the terms "copolymer" or "interpolymer" (used to refer to a polymer prepared by polymerizing two or more different monomers, with the understanding that trace amounts of impurities may be incorporated into the polymer structure). Trace amounts of impurities (e.g., catalyst residues) may be incorporated into and / or present within the polymer. The polymer may be a single polymer or a polymer blend.

[0024] The term "interpolymer" refers to a polymer prepared by polymerizing at least two different types of monomers. Thus, the general term "interpolymer" includes copolymers and other polymers prepared by polymerizing more than two different monomers such as terpolymers.

[0025] As used herein, the terms "comprising," "including," "having," and derivatives thereof are not intended to exclude the presence of any additional components, steps, or procedures, whether or not specifically disclosed. To avoid any doubt, all compositions claimed through the use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless there is a contradictory description. In contrast, the term "consisting essentially of" excludes any other components, steps, or procedures from the scope of any subsequent description, except for those that are not essential for operation. The term "consisting of" excludes any component, step, or procedure not specifically depicted or listed.

[0026] As used throughout this specification, the following abbreviations have the following meanings, unless otherwise clearly indicated by the context. "=" means "equal to," "@" means "at," "~" means "approximately," "<" means "less than," "≦" means "less than or equal to," ">" means "greater than," "≧" means "greater than or equal to," "I2" means "melt index," g = gram, mg = milligram, phr = parts per 100 of resin, kg = kilogram, g / cc = grams per cubic centimeter, kg / m 3 = kilograms per cubic meter, g / mol = grams per mole, L = liter, mL = milliliter, g / L = grams per liter, Mw = weight-average molecular weight, Mn = number-average molecular weight, Mz = z-average molecular weight, m = meter, mm = millimeter, cm = centimeter, min = minute, s = second, hr = hour, mPa = megapascal, MPa = megapascal, N = newton, mm 2= square millimeter, g / 10 min = grams per 10 minutes, % = percent, wt% = weight percent, cpm = cycles per minute, and N / mm = newtons per millimeter.

[0027] Unless otherwise specified, all amounts such as percentages, parts, ratios, etc. are defined by weight. For example, all percentages specified in this specification are weight percentages (wt%) unless otherwise indicated.

[0028] Temperatures are in degrees Celsius (°C), and "ambient temperature" or "room temperature" means 20°C to 25°C unless otherwise specified.

[0029] In a broad embodiment, the present invention relates to a foamable formulation or composition useful for producing a foam product or foam article, the composition comprising, for example, a combination, blend, or mixture of: (a) at least one elastomer selected from the group consisting of (i) an ethylene / alpha-olefin multiblock interpolymer, (ii) an ethylene / alpha-olefin elastomer, and (iii) combinations thereof; (b) at least one ethylene vinyl acetate; (c) at least one polarity modifier selected from the group consisting of (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) combinations thereof; (d) at least one crosslinking agent; and (e) at least one foaming agent.

[0030] In some embodiments, the above composition is advantageously used to make a foam product or foam article for use in footwear applications. In one embodiment, the foam product or foam article is a footwear component joined to one or more other different components of a shoe.

[0031] In some embodiments, the foam composition is, for example, (a) Based on the foaming composition, 45 wt% to 100 wt% of one or more elastomers selected from the group consisting of (i) an ethylene / alpha-olefin multi-block interpolymer having a density of 0.850 g / cc to 0.890 g / cc and an I2 of 0.5 g / 10 min to 50 g / 10 min, (ii) an ethylene / alpha-olefin elastomer having a density of 0.850 g / cc to 0.890 g / cc and an I2 of 0.5 g / 10 min to 50 g / 10 min, and (iii) combinations thereof, (b) Based on the foaming composition, 5 wt% to 35 wt% of one or more ethylene vinyl acetates, (c) Based on the foaming composition, 10 wt% to 40 wt% of one or more polarity modifiers selected from the group consisting of (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) combinations thereof, (d) Based on the foaming composition, 1 wt% to 3 wt% of one or more crosslinking agents, (e) Based on the foaming composition, 1 wt% to 3 wt% of one or more foaming agents, and

[0032] Optionally, the composition may also contain one or more additives of component (f) if desired.

[0033] In one preferred embodiment, the foam composition comprises, for example, (a) an elastomer containing an olefin block copolymer (at least 50 phr) (e.g., INFUSE™, a product available from The Dow Chemical Company), and / or a polyolefin elastomer (e.g., ENGAGE™, a product available from The Dow Chemical Company), (b) EVA (e.g., ELVAX™, a product available from The Dow Chemical Company), (c) ethylene-methyl acrylate at a concentration of 10 phr to 40 phr (e.g., ELVALOY™ AC, a product available from The Dow Chemical Company), (d) a crosslinking agent such as a peroxide that is at least 99% pure, and (e) a foaming agent such as azodicarbonamide. The foam composition may include one or more optional additives, such as accelerators (e.g., ZnO and / or ZnSt), and fillers (e.g., CaCO3 and / or TiO2).

[0034] In one general embodiment, the expansion ratio of the foam composition is 1.5 to 1.6.

[0035] In one general embodiment of the present invention, the foamable composition useful for preparing a foam article comprises, for example, at least one elastomer. Examples of elastomers useful for preparing the foamable composition of the present invention, as component (a), include polyolefin elastomers (POE), olefin block copolymers (OBC), and mixtures thereof. In a preferred embodiment, the elastomer comprises a mixture of an olefin block copolymer (OBC) and other polyolefin polymers.

[0036] Examples of some commercially available elastomers useful for preparing the foamable composition of the present invention include, for example, INFUSE™ OBC 9500 (available from The Dow Chemical Company), Tafmer DF740 (available from Mitsui), and mixtures thereof.

[0037] In some embodiments, the elastomers useful in the present invention include elastomers having a density of from 0.850 g / cc to 0.890 g / cc in one general embodiment, from 0.850 g / cc to 0.880 g / cc in another embodiment, and from 0.850 g / cc to 0.870 g / cc in still another embodiment. In some embodiments, the elastomers useful in the present invention include elastomers having an I2 of from 0.5 g / 10 min to 50 g / 10 min in one general embodiment, from 0.5 g / 10 min to 30 g / 10 min in another embodiment, and from 1 g / 10 min to 30 g / 10 min in still another embodiment.

[0038] The elastomer used in the preparation of the foaming composition can be present in the foaming composition in an amount of from 45 wt% to 100 wt%, in another embodiment from 45 wt% to 90 wt%, and in still another embodiment from 45 wt% to 70 wt% based on the total amount of the components in the foaming composition.

[0039] In one general embodiment of the present invention, the foaming composition useful for preparing the foam article includes, for example, at least one ethylene vinyl acetate (EVA). Examples of EVA useful for preparing the foaming composition of the present invention, as component (b), include various grades of EVA, for example, EVA having a vinyl acetate (VA) level of 18 wt% VA to 35 wt% VA in one general embodiment, EVA having a VA level of 18 wt% VA to 32 wt% VA in another embodiment, EVA having a VA level of 18 wt% VA to 28 wt% in still another embodiment, and mixtures thereof.

[0040] Examples of some commercially available EVA compounds useful for preparing the foaming composition of the present invention include, for example, ELVAX™ 460 (available from The Dow Chemical Company), EVA 3019PE (available from Braskem Company), and mixtures thereof.

[0041] In the preparation of the foaming composition, the EVA used can be present in the foaming composition in an amount of 5% to 35% by weight in one general embodiment and 10% to 35% by weight in another embodiment, based on the total amount of the components in the foaming composition.

[0042] In one general embodiment of the present invention, a foaming composition useful for preparing a foam article includes, for example, at least one polarity regulator. Examples of the polarity regulator, component (c), useful for preparing the foaming composition of the present invention include, for example, at least one copolymer of ethylene and (meth)acrylate. As used herein, “(meth)acrylate” means acrylate and / or methacrylate. For example, in some embodiments, the (meth)acrylate can include methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, and mixtures thereof. In some embodiments, the copolymer of the present invention can include, for example, ethylene-(meth)acrylate which can include ethylene-methyl acrylate, ethylene-butyl acrylate, and mixtures thereof. In a preferred embodiment, the polarity regulator includes, for example, ethylene-methyl acrylate and a mixture of ethylene-methyl acrylate with other acrylates.

[0043] Examples of some commercially available polarity regulator compounds useful for preparing the foaming composition of the present invention include, for example, ELVALOY™ AC acrylate copolymer (available from The Dow Chemical Company), and mixtures of ELVALOY™ AC acrylate copolymer with other conventional acrylate copolymers.

[0044] In the preparation of the foaming composition, the polarity regulator used can be present in the foaming composition in an amount of 5% to 50% by weight, in another embodiment 10% to 40% by weight, in still another embodiment 10% to 30% by weight, and in yet another embodiment 10% to 20% by weight, based on the total amount of the components in the foaming composition.

[0045] In one general embodiment of the present invention, a foaming composition useful for preparing a foam article includes, for example, at least one crosslinking agent.

[0046] Examples of crosslinking agents, component (d), useful for preparing the foaming composition of the present invention include, for example, dicumyl peroxide and mixtures of dicumyl peroxide with other crosslinking agents.

[0047] Examples of some commercially available crosslinking agent compounds useful for preparing the foaming composition of the present invention include, for example, Luperox DC40P-SP2 (available from Arkema), Luperox 101 (available from Arkema), and mixtures thereof.

[0048] The crosslinking agent used in the preparation of the foaming composition can be present in the foaming composition at a concentration of ≧1% by weight in one general embodiment and 1% to 3% by weight in another embodiment, based on the total amount of the components in the foaming composition.

[0049] In one general embodiment of the present invention, a foamable composition useful for preparing a foam article includes, for example, at least one foam generating agent. The foam generating agent can be, for example, a blowing agent mixed in the foamable formulation, a gaseous material or substance added to the foamable composition by physical means such as a foaming device known to those skilled in the art of forming foams, or a foam generating material such as a mixture thereof. A "blowing agent" is a substance capable of producing a cellular structure in the foamable composition through a foaming process. Blowing agents are used to foam dynamically crosslinked polymers. The blowing agent used in the present invention is not particularly limited as long as the blowing agent can expand crosslinked particles.

[0050] Examples of suitable blowing agents for making the foam of the present invention can include, but are not limited to, (I) inorganic blowing agents, (II) organic blowing agents, (III) chemical blowing agents, and (IV) combinations thereof. Some blowing agents useful in the present invention are disclosed, for example, in Sendijarevic et al., "Polymeric Foams And Foam US 7,666,918 B2 25 Technology," Hanser Gardner Publications, Cincinnati, Ohio, 2nd edition, Chapter 18, pages 505 - 547 (2004).

[0051] Non - limiting examples of suitable inorganic physical blowing agents, component (I), useful in the present invention include carbon dioxide, nitrogen, argon, water, air, helium, oxygen, neon, and mixtures thereof.

[0052] Suitable organic physical blowing agents useful in the present invention, non-limiting examples of component (II) include: (1) aliphatic hydrocarbons having 1 to 6 carbon atoms such as methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, and mixtures thereof; (2) aliphatic alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, and mixtures thereof; (3) cycloaliphatic hydrocarbons such as cyclohexane, cyclopentane, and mixtures thereof; and (4) fully and partially halogenated aliphatic hydrocarbons having 1 to 4 carbon atoms such as (i) fluorocarbons, (ii) chlorocarbons, (iii) chlorofluorocarbons, and (iv) mixtures thereof.

[0053] Suitable fluorocarbons useful in the present invention, non-limiting examples of component (4)(i) include methyl fluoride, perfluoromethane, ethyl fluoride, 1,1-difluoroethane (HFC152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane, difluoromethane, perfluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, 1,1-difluoropropane, perfluorobutane, perfluorocyclobutane, chlorofluoromethane, trifluoromethane, and mixtures thereof.

[0054] Non-limiting examples of suitable partially halogenated chlorocarbons, component (4)(ii), and chlorofluorocarbons, component (4)(iii), useful in the present invention include dialkyl ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, and mixtures thereof, methyl chloride, methylene chloride, ethyl chloride, 1,1,1-trichloroethane, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123), 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), dichloropropane, and mixtures thereof.

[0055] Non-limiting examples of suitable fully halogenated chlorofluorocarbons, component (4)(iii), useful in the present invention include trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), dichlorotetrafluoroethane (CFC-114), chloropentafluoropropane, dichlorotetrafluoropropane, and mixtures thereof.

[0056] Non-limiting examples of suitable chemical blowing agents, component (III), useful in the present invention include azodicarbonamide, azodiisobutyronitrile, benzenesulfonohydrazide, 4,4'-oxybis(benzenesulfonyl) semicarbazide, p-toluenesulfonyl semicarbazide, barium azodicarboxylate, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, trihydrazinotriazine, and mixtures thereof.

[0057] Any of the blowing agents described above may be used alone or in combination of two or more of them. In one preferred embodiment, the blowing agent used in the present invention is at least one of the inorganic physical blowing agents because the inorganic physical blowing agents are not known to reduce the ozone layer and are relatively inexpensive. In some embodiments, the inorganic physical blowing agent used is one or more blowing agents selected from the group consisting of nitrogen, air, carbon dioxide (CO2), and mixtures thereof. In some embodiments, the crosslinking step and the foaming step described above are carried out as a series of steps in different containers.

[0058] In other embodiments, the blowing agent useful in the present invention is selected from the group consisting of azodicarbonamide, isobutane, CO2, or mixtures thereof. In one preferred embodiment, the blowing agent, component (e), useful for preparing the foaming composition of the present invention includes, for example, azodicarbonamide, and mixtures of azodicarbonamide and any one or more of the other aforementioned blowing agents.

[0059] Examples of some commercially available blowing agent compounds useful for preparing the foaming composition of the present invention include, for example, Celogen AZ130 (available from Lion Copolymer), Unicell D300 (available from DONGJIN SEMICHEM CO., LTD.), and mixtures thereof.

[0060] In one preferred embodiment, the blowing agent is used to prepare the foaming composition, and the blowing agent can be present in the foaming composition at a concentration of ≧1 wt% in one general embodiment and 1 wt% - 3 wt% in another embodiment based on the total amount of the components in the foaming composition.

[0061] In some embodiments, the foamable composition of the present invention can include a wide variety of other optional additives. The additives in combination with the composition of the present invention may be formulated to enable the performance of specified functions while maintaining the excellent advantages / characteristics of the composition. For example, the following additives may be blended into the formulated resin composition to form the foamable composition of the present invention. Additives include accelerators such as zinc oxide (ZnO) and / or zinc stearate (ZnSt), fillers such as calcium carbonate (CaCO3), nucleating agents, antioxidants, pigments, colorants such as titanium dioxide (TiO2) for providing white color, UV stabilizers, UV absorbers, processing aids, compatibilizers, other polymer resins, etc., and mixtures thereof.

[0062] Optional additives, when used in the foamable composition, may be added to the foamable composition in an amount of ≤10 wt%, in another embodiment ≤5 wt%, in still another embodiment ≤3 wt%, and in yet another embodiment ≤1 wt% based on the total amount of the components in the foamable composition. In other embodiments, the optional additives may be added to the foamable composition in an amount of 0 wt% to 10 wt%, in another embodiment 0.05 wt% to 5 wt%, in still another embodiment 0.1 wt% to 5 wt%, in yet another embodiment 1 wt% to 5 wt%, and in still yet another embodiment 1 wt% to 3 wt% based on the total amount of the components in the foamable composition.

[0063] In one broad embodiment of the present invention, the process for making the foamable composition includes, for example, mixing or blending the components (a)-(e) described above and any desired optional component (f) described above. The processes and apparatuses used to mix the components are well known to those skilled in the art of mixing. For example, the mixing process for producing foam products can include an injection molding process or a bun foam process. In one preferred embodiment, the bun foam process is used, and this type of mixing process generally includes the following general procedures.

[0064] Weigh all the components of the foaming composition and add them to a closed mixer. The rotor speed of the closed mixer is maintained at a speed that allows the mixing of the components without generating excessive shear heating that could prematurely activate the peroxide or foaming agent components in the foaming composition. In one general embodiment, a rotational speed in the range of 75 rpm to 100 rpm (rotations per minute, rpm) is used to initially melt the polymer that is first added to the mixer alone. Then, the rpm of the mixer is reduced to about 50 rpm, and the remaining components are added to the mixer. The rpm and time for mixing the components will depend on the batch (i.e., the mixture of components in the mixer) temperature. For example, in one general embodiment, the rotor speed of the closed mixer is adjusted to maintain the batch temperature in the range of 120°C to 130°C. In other embodiments, a slow rotor speed may require additional mixing time for the components in the mixer to complete the batch. For example, the time for mixing the batch at the rotor speed described above can be carried out for 10 minutes to 15 minutes in one general embodiment.

[0065] After all the components are added to the mixer and thoroughly mixed, the batch is dropped from the mixer into a catch pan having a non-stick liner (e.g., a polyethylene terephthalate (PET) film). The batch in the catch pan is then quickly transferred to a roll mill station where the batch is placed in a heated roll mill. The roll mill is typically heated (e.g., to 90°C to 105°C) to prevent the batch from solidifying during the finishing process of the batch and to allow for further mixing of any components that may have migrated to the surface of the batch while exiting the closed mixer.

[0066] In some embodiments, the batch can be passed through the roll mill once, and in other embodiments, the batch can be passed through the roll mill once, folded, and then passed through the roll mill three or four more times to aid in the dispersion of any components remaining on the surface of the batch. Cooling the batch below the polymer freezing point (Tc) should be avoided. This is because if the batch is cooled below Tc, the surface of the resulting formed "sheet" will become non-uniform. After rolling the sample batch through the roll mill for 1 to 2 minutes to form the sheet, the sheet is removed from the roll mill and cooled to 20°C in preparation for foam molding.

[0067] In some embodiments, the thickness of the sheet is sufficient to fill the molding chase by stacking 1 to 3 sheets within the molding chase. By minimizing the number of sheets stacked within the molding chase, the possibility of generating voids between the layers of the sheet is reduced. In one preferred embodiment, the sample sheet stacked within the molding chase is sandwiched between two layers of release film. The sample is then placed between the two platens of the molding chase. The two platens are closed and the sample is compressed.

[0068] Some of the advantageous / beneficial properties exhibited by the foamable composition produced according to the mixing process described above can include, for example: the foamable composition can be easily produced, i.e., the different components (a)-(e) of the foamable composition, and optionally (e), can be easily and more equally (uniformly or homogeneously) dispersed, improving the processability of the foamable composition, i.e., the foam product can be easily manufactured from the ease of processing the foamable composition. When a foam article is manufactured using the foamable composition, the foam article exhibits specially improved properties such as bond strength and the other properties described herein below, and meets the requirements of a particular target end-use application while maintaining other mechanical and thermal properties of the foam article.

[0069] For example, in some embodiments, the addition of POE / OBC elastomers to the EVA foam improves the mechanical properties due to the molecular architecture of these elastomers. The addition of these elastomers improves density reduction, hardness reduction, shrinkage reduction, increased resilience, and increased recovery after compression set.

[0070] In some embodiments, the present invention is directed to the above-described foamable composition for use in making a formed foam article. In other embodiments, the present invention is directed to a process for producing a formed foam article from the above-described foamable composition. In one preferred embodiment, the formed foam article is useful in footwear applications such as shoe parts where the foam article is incorporated into footwear used in the footwear industry. The foam articles of the present invention have a combination of good properties. For example, one surprising property of the present invention is that the foam product exhibits a high level of bond strength without adversely affecting other properties of the foam product.

[0071] Referring to FIG. 1, an embodiment of a multilayer structure generally designated by reference numeral 10 is shown, including several layers, such as a foam layer 11, a primer layer 12, an adhesive layer 13, and a PVC layer 14. Layers 11 to 14 can be different films and / or substrates of different materials joined to each other to form the multilayer structure 10. The multilayer structure 10 is used as a test specimen for performing a bonding test on such a test specimen (i.e., for testing the bonding strength of the foam layer 11 of the multilayer structure 10). One object of the present invention is to bond a foam member layer, such as the foam layer 11 (non-polar substrate), to a different substrate, such as a transparent PVC layer 14 (polar layer). In the embodiment shown in FIG. 1, the above object is achieved, for example, by bonding a foam sample member layer 11 having an upper outer side 11A and a bottom inner side 11B to a transparent PVC layer 14 having an upper outer side 14A and a bottom inner side 14B. The foam sample member layer 11 is bonded to the PVC layer 14 via a primer layer 12 having an upper side 12A and a bottom side 12B and a polyurethane-based adhesive layer 13 having an upper side 13A and a bottom side 13B to form the multilayer structure 10. The primer layer 12 and the adhesive layer 13 are sandwiched and disposed between the innermost side 11B of the foam member layer 11 and the innermost side 14B of the PVC layer 14. The upper side 12A of the primer layer 12 is attached to the bottom innermost side 11B of the foam layer 11, the bottom side 13B is attached to the bottom innermost side 14B of the PVC layer 14, the bottom side 12B of the primer layer 12 is attached to the upper side 13A of the adhesive layer 13, and all of the layers 11 to 14 form the multilayer structure 10, and the sample foam member 11 (non-polar substrate) is bonded to the transparent PVC member 14 (polar material). The bonding strength shown between the two layers (the foam layer 11 and the PVC layer 14) is increased compared to known materials that do not add a polar material to the foam layer 11.

[0072] Referring to FIG. 2, there is shown an image generally designated by reference numeral 20 of three separate groups of test specimens of the present invention generally designated by reference numerals 21, 22, and 23, which are specimens produced to have an essentially identical multilayer structure (foam layer 11, primer layer 12, adhesive layer 13, and PVC layer 14) as shown in FIG. 1. Each of the three test specimens 21 - 23 shown in FIG. 2 includes two separate torn test specimen pieces (21a and 21b, 22a and 22b, and 23a and 23b for test specimens 21, 22, and 23, respectively) formed when the test specimens 21 - 23 broke (or delaminated) into two pieces after the test specimens were subjected to a joint performance test.

[0073] Generally, the joint strength test of the three test specimens 21 - 23 of the present invention results in the visual occurrence of breakage (or delamination) in the multilayer structure after the joint test, and the joint strength test produces (or manufactures) two separate torn test specimen pieces 21a - 23a and 21b - 23b of the foam layer shown in FIG. 2 for each of the three test specimens 21 - 23 tested. In the upper perspective view of FIG. 2, the first test specimen pieces 21a - 23a are shown with the upper outer side of the test specimen pieces 21a - 23a (similar to the upper outer side 11A of the foam layer 11 shown in FIG. 1) visually facing upward, and the second test specimen pieces 21b - 23b are shown with the upper outer side of the test specimen pieces 21b - 23b (similar to the upper outer side 11A of the foam layer 11 shown in FIG. 1) visually facing downward. In each of the test specimen pieces 21a - 23a, a part of the PVC layer 21c - 23c is shown with the bottom inner side of a part of the PVC layer (similar to the bottom inner side 14B of the PVC layer 11 shown in FIG. 1) visually facing upward.

[0074] Referring again to FIG. 2, as described above, for example, three test specimens 21-23 of the present invention in their fractured forms are shown, including (1) a first test specimen 21 including test specimen pieces 21a and 21b, (2) a second test specimen 22 including test specimen pieces 22a and 22b, and (3) a third test specimen 23 including test specimen pieces 23a and 23b. After performing a bonding test on each test specimen, all three test specimens 21-23 fractured at the bonding interface between the foam layer test specimen pieces 21a, 22a, and 23a and the PVC layer. The foam test specimen pieces 21b, 22b, and 23b of the three test specimens 21, 22, and 23 were either torn or fractured (and separated) from the foam test specimen pieces 21a-23a, respectively. The fracture of the layers in the multilayer structure of the test specimens 21-23 visually observable to the naked eye occurred after the three test specimens 21-23 were subjected to the bonding test. The occurrence of the fracture is a desirable occurrence because such occurrence indicates that the bonding between the foam layer (i.e., the combined test specimen pieces 21a-23a and test specimen pieces 21b-23b before fracture) and the PVC layer (see parts 21c-23c of the test specimens 21-23, respectively) is effective.

[0075] The foam layers of all three test specimens 21-23 shown in FIG. 2 constitute the foam layers of the test specimens 21-23 and are produced using substantially the same foaming formulation of the present invention having the multilayer structure 10 shown in FIG. 1. In addition, the other layers (primer layer 12, adhesive layer 13, and PVC layer 14) of the three test specimens 21-23 are also made using the same materials for each of the three test specimens 21-23 of the present invention. The foaming formulation used to produce the foam layers of the test specimens 21-23 includes, for example, at least 50 phr of an elastomer and at least 30 phr of a copolymer of ethylene and methyl acrylate.

[0076] Referring to FIG. 3, there is shown an image generally designated by reference numeral 30 of three separate groups of comparative specimens generally designated by reference numerals 31, 32, and 33, which were produced to have essentially the same multilayer structure (foam layer 11, primer layer 12, adhesive layer 13, and PVC layer 14) as shown in FIG. 1. Each of the three specimens 31 - 33 shown in FIG. 3 includes two separate comparative specimen pieces (for specimens 31, 32, and 33, 31a and 31b, 32a and 32b, and 33a and 33b, respectively).

[0077] Generally, the joint strength tests of the three comparative specimens 31 - 33 do not result in the visual occurrence of breakage (or delamination) in the multilayer structure after the joining test. Instead, the joint strength tests of the three comparative specimens 31 - 33 produce (or generate) two separate, un-torn (or unbroken or un-delaminated) specimens of the intact foam layer specimens 31a - 33a and the intact PVC layer specimens 31b - 33b as shown in FIG. 3 for each of the three specimens 31 - 33 tested. The two separate specimen pieces 31a - 33a and 31b - 33b are formed when specimens 31 - 33 peel into two separate, un-torn (or unbroken or un-delaminated) specimen pieces 31a - 33a and 31b - 33b after specimens 31 - 33 have been subjected to the joint performance test. Thus, the joint strength tests of the three comparative specimens 31 - 33 result in the visual occurrence of peeling or separation of the foam layer from the PVC layer present in the multilayer structure of the three comparative specimens 31 - 33. In the upper perspective view of FIG. 3, the first specimen pieces 31a - 33a are shown with the upper side (similar to the upper outer side 11A of the foam layer 11 shown in FIG. 1) of the foam specimen pieces 31a - 33a visually facing upward, and the second specimen pieces 31b - 33b are shown with the upper side (similar to the upper outer side 11A of the foam layer 11 in FIG. 1) of the specimen pieces 31b - 33b visually facing downward.

[0078] Referring back to FIG. 3, as described above, for example, three comparative test specimens 31-33 in their separated forms are shown, including (1) a first test specimen 31 including test specimen pieces 31a and 31b, (2) a second test specimen 32 including test specimen pieces 32a and 32b, and (3) a third test specimen 33 including test specimen pieces 33a and 33b. After performing a bonding test on each test specimen, all three test specimens 31-33 separated at the respective bonding interfaces between the foam layers 31a, 32a, and 33a and the PVC layers 31b, 32b, and 33b of the three test specimens 31, 32, and 33. After subjecting the three comparative test specimens 31-33 to a bond strength test, the occurrence of breakage (or delamination) in the layers of the multilayer structure was not visually observed with the naked eye. The absence of breakage / delamination in the test specimens 31-33, particularly when the layers of the foam test specimen pieces 31a-33a do not contain a polarity regulator, demonstrates that the bonding between the layers of the respective foam test specimen pieces 31a-33a and the PVC test specimen pieces 31b-33b of the test specimens 31-33 is not effective, which is undesirable.

[0079] The three test specimens 31-33 shown in FIG. 3 are comparative examples of foam articles having a multilayer structure as shown in FIG. 1 and are made from known materials without adding a polar material to the foam layers of the comparative test specimens 31-33. Therefore, the three comparative test specimens 31-33 shown in FIG. 3 are different from the three test specimens 21-23 of the present invention in FIG. 2. All three test specimens 31-33 shown in FIG. 3 have an essentially the same multilayer structure as that shown in FIG. 1, and all three test specimens are produced using a substantially the same foamable formulation that constitutes the layers of the foam test specimen pieces 31a-33a, except that the foamable formulation constituting the layers of the foam test specimen pieces 31a-33a contains at least 50 phr of an elastomer but does not contain a copolymer of at least 30 phr of ethylene and methyl (or butyl) acrylate (polar material), similar to the foam layer 11 shown in FIG. 1.

[0080] In one broad embodiment of the present invention, the process for making a foam article includes using any conventional foam forming process such as processes and apparatus well known to those skilled in the art of producing foam, for example.

[0081] Generally, the process for manufacturing the foam article of the present invention includes the following general procedures.

[0082] In some embodiments, a roll mill sheet (or molding plate sample) is first prepared using the general procedures described above. The roll mill sheet is then cut into a square having dimensions of 80 mm × 80 mm × 2 mm, and the square is placed inside a preheated ban-foam mold or “chase”. The mold dimensions can vary depending on the size of the compression molding machine used to cure the sample. In one general embodiment, for example, the mold dimensions can be 100 mm × 100 mm × 10 mm.

[0083] In some embodiments, a dry lubricant (e.g., a dry polytetrafluoroethane (PTFE) lubricant such as Fluoroglide) is sprayed onto the surface of the chase to avoid adhesion of the foam to the chase during demolding. The roll mill sheet (or molding plate) is cut into pieces that fit the lubricated chase and stacked to provide a little extra material sufficient to completely fill the chase after preheating and pressing. A rubber knife is used to cut the sheet. The pieces of sheet are weighed to ensure that sufficient material is added to the chase. The mass of the sample used to fill the chase can be calculated by taking the volume of the chase and multiplying it by the calculated density of the sheet. Adding 10% extra to the resulting mass will be sufficient to completely fill the chase.

[0084] The "molding tray" used to support the sample during preheating and curing can be, for example, a smooth and flat metal tray with a handle grip for holding during transfer between presses. On top of the smooth tray, a thin metal sheet can be used to ensure that the surface of the foam is smooth. To avoid extruding the material from the chase before it is fully melted, a minimum pressure is applied during this initial preheating.

[0085] In some embodiments, the preheating process lasts for 8 minutes at 110°C for POE foam and 8 minutes at 120°C for OBC foam. After the preheating process, the pressure applied to the sample is increased to 20 tons for 4 minutes. The preheating and pressing processes are used to sufficiently remove air pockets inside the sample and between the stacked layers before curing the sample. Omitting the preheating and pressing processes may result in voids being formed in the final sample and limit the useful area of the ban foam produced for testing.

[0086] After applying a pressure of 20 tons to the sample for 4 minutes, the pressure is released and the tray with the sample is immediately transferred to the curing press. The curing press is operated at 180°C for 8 minutes, applying a total pressure of 177,932 N on a 5.1 cm ram to the sample. When the 8-minute curing time has elapsed, the pressure on the sample is released, the press platens open immediately, and the foam pops out of the mold but remains in the tray until it can be quickly removed from the press.

[0087] Some of the advantageous / beneficial properties exhibited by the foam articles produced according to the process described above can include, for example, (1) improved bond strength, (2) compression set, (3) shrinkage, (4) hardness, and (5) resilience.

[0088] In some embodiments, the bond strength of the foam articles of the present invention is, for example, 1 N / mm to 5 N / mm in one general embodiment, 1 N / mm to 3.5 N / mm in another embodiment, and 1 N / mm to 1.5 N / mm in yet another embodiment.

[0089] In some embodiments, the compression set of the foam article is, for example, 15% - 60% in one general embodiment, 15% - 50% in another embodiment, and 15% - 40% in yet another embodiment.

[0090] In some embodiments, the shrinkage of the foam article is, for example, 0% - 2% in one general embodiment, 0.2% - 2% in another embodiment, 0.3% - 1.5% in yet another embodiment, and 0.4% - 1.2% in still another embodiment.

[0091] In some embodiments, the hardness of the foam article is, for example, 25 Shore A - 50 Shore A in one general embodiment, 25 Shore A - 40 Shore A in another embodiment, and 25 Shore A - 30 Shore A in yet another embodiment.

[0092] The resilience of the foam article is, for example, 40% - 60% in one general embodiment, 40% - 50% in another embodiment, and 40% - 45% in yet another embodiment.

[0093] The foamable composition described above and the foam products made therefrom can be used, for example, in footwear applications, bedding applications, insole applications, casual shoe applications, and monoblock shoe applications.

Examples

[0094] The following Inventive Examples (Inv.Ex.) and Comparative Examples (Comp.Ex.) of the present invention (collectively referred to as "Examples") are presented in this specification to explain the features of the present invention in more detail, but are not intended to be construed as limiting the scope of the claims, either explicitly or implicitly. The Inventive Examples of the present invention are identified by Arabic numerals, and the Comparative Examples are represented by alphabetical characters. In the following experiments, the performance of the embodiments of the compositions described in this specification was analyzed. Unless otherwise specified, all parts and percentages are by weight based on the total weight. Abbreviations and Notations

[0095] Various terms, notations, and raw materials used in the Inventive Examples (Inv.Ex.) and Comparative Examples (Comp.Ex.) of the present invention are explained as follows.

[0096] "ER" represents the expansion ratio.

[0097] "Dyn Cset" represents the dynamic compression set.

[0098] "Static Cset" represents the static compression set. Raw Materials

[0099] The components / raw materials used in the Examples are listed in Table I below.

Table 1

[0100] A closed mixer such as a Banbury mixer or a Thermo Haake mixer (available from Thermofisher) with a tangential rotor is used to mix the foaming formulation. This type of closed mixer is commonly used in the footwear industry. Also, a kneader mixer type can also be used to mix the formulation. The tangential rotor of the mixer provides mixing, and mixing also occurs between the wall of the chamber and the tip of the rotor blade. The following conditions / parameters are used: The initial temperature of mixing is 80 °C, and the volume of 379 cm 3 , a filling rate of 70%, and a rotation of 60 rpm. Each formulation is produced in four batches such that there is sufficient material to produce foam samples for all tests.

[0101] An open mill such as a Cope mixer (a two-roll counter-rotating mill available from Cope, a Brazilian manufacturer of rubber mixing machinery) is used to homogenize the aforementioned four batches of each formulation and produce a thin sheet (having a thickness of about 2 mm). The following conditions / parameters are used: An initial temperature of 90 °C and a rotation of 14 rpm.

[0102] A Compound RPA (Rubber Processing Analyzer) is used to measure the effects of the blowing agent and peroxide on the curing behavior of the produced compound. The cross-linking characteristics of the sample are evaluated by a rheometric curve using the following conditions / parameters: a deformation of + / -0.5° Arc, a frequency of 100 cpm, a temperature of 170 °C, and a test of 15 minutes, according to the procedure described in ASTM D5289-17.

[0103] Test specimens of the foam samples are produced from the foaming formulation samples using a mold having dimensions of 100 mm × 100 mm × 10 mm. Each test specimen is cross-linked by compression molding at a temperature of 170 °C (based on the RPA results) for 10 minutes. A high-speed open press (available from FKL, a Brazilian manufacturer) is used for compression molding. Examples 1 - 6 and Comparative Examples A - E

[0104] Generally, a foam composition or formulation contains the following components: an olefin block copolymer (OBC) such as INFUSE™ 9500, or a polyolefin elastomer (POE) such as ENGAGE™ 8200, an EVA compound such as ELVAX™ 460, an ethylene - methyl acrylate such as ELVALOY™ AC 1330, or an ethylene - butyl acrylate such as ELVALOY™ AC 3427, a cross - linking agent such as a peroxide having a purity of at least 99%, and a blowing agent such as azodicarbonamide. For example, one or more optional components including accelerators such as ZnO and / or ZnSt, and fillers such as CaCO3 and / or TiO2 can be added to the formulation. The formulations used in the examples are described in Table II.

[0105] The expansion ratio (ER) of the foamable formulation is generally 150% - 160% in one general embodiment, 150% - 155% in another embodiment, and 155% - 160% in yet another embodiment. To obtain other expansion ratios, the component / raw material levels of the foamable formulation can be optionally adjusted. [Table 2] Foam Products Examples 7 - 12 and Comparative Examples F - J General Procedure for Preparing Foam Samples

[0106] Using the foamable formulation samples described above, slab foam samples are produced according to the procedure described in ASTM D3182 - 16. The properties of the obtained foam samples are described in Table III. [Table 3]

[0107] The form samples of Inv.Ex. using ELVALOY™ AC 1330 at a concentration of 30 phr exhibit good bond strength in addition to a good balance of properties. For example, in addition to reaching the desired minimum bond strength of 2.5 N / mm, the samples of Inv.Ex. 12 showed failure of the bond test in the form of breakage of the EVA foam desirable in the present invention.

[0108] The aged samples (stored at room temperature for 5 months) were tested for the second bond using the same PVC sheet, the same primer, and the same adhesive according to the same procedure described above. As shown in Table IV, the results of the bond strength for the foam samples varied compared to the results of the first bond strength described above. Generally, when measuring the bond strength of the aged foam samples, it was found that the bond strength was improved.

[0109] One hypothesis for the improved bond strength by the aged foam, although not limited thereby, is the presence of unreacted crosslinking agents and / or blowing agents remaining in the foam, and during aging, these unreacted raw materials changed the structure of the foam to improve the bond strength. [Table 4] Notes on Table IV: (1) "ER" represents the expansion ratio. (2) "ΔBS" represents the difference between bond strengths. (3) "Rd" represents round. (4) "Ave.BS" represents the average bond strength. (5) "Adh." represents adhesiveness. (6) "Rup." represents rupture. (7) "Delam." represents delamination. Test method Expansion ratio (ER)

[0110] The general procedure for measuring the expansion ratio (ER) of a banfoam sample is performed by measuring the initial length of the banfoam sample and the final length of the banfoam sample. After cooling at room temperature for 2 hours, the final length of the foam sample is measured. Then, the ER of the banfoam sample is calculated using the following formula. ((Final length) - (Initial length)) / (Initial length).

[0111] Foam samples having similar ERs also have comparable mechanical properties to each other on the same basis, so foam samples having similar ERs are used in the test. ER affects foam density, and density is related to many of the physical and mechanical properties of the foam such as hardness, compression set, and resilience. The target for ER measurement of the foam sample is in the range of 150% - 160%. Foam density (with skin)

[0112] The hydrostatic density is measured according to the method described in ISO 2781-18, Method A. The foam sample to be tested is cut from the banfoam with skin. The banfoam template is weighed in 0.1 g units, and the volume of the banfoam template is determined by measuring the length, width, and thickness in 0.01 cm units without removing the skin layer. Hardness Asker C

[0113] The Asker C hardness measurement is performed using a durometer device that measures the indentation hardness of the foam material. The Asker C hardness of the foam sample is measured using the method described in NBR 14455-15. In this test method, a standardized indenter is pressed against and into the test piece (foam sample with skin) to cause vertical penetration of the indenter into the test piece. The indenter is applied onto the foam sample with skin for 3 seconds. Hardness Shore A

[0114] The Shore A hardness of the foam sample is determined using the method described in ASTM D2240-15. In this test method, a standardized indenter is pressed against and into the test specimen (foam sample with skin) to cause vertical indentation of the indenter into the test specimen. The indenter is applied to the foam sample with skin for 1 second. Static compression set

[0115] The compression set of the foam sample is measured according to the procedure described in ASTM D395-18, Method B. Using this test method, 25% compression is applied to the foam sample with skin at a temperature of 70 °C in an oven for 4 hours. The deformation (and resulting recovery) of the foam sample is measured 30 minutes after removing the sample from the oven. Shrinkage

[0116] The shrinkage of the expanded foam sample is evaluated according to the procedure established by the German Institute PFI (Pruf und Forschungsinstitut Pirmasens e.v.). Before oven-aging the sample at 70 °C for 4 hours, the dimensions of three test specimens of the foam sample with skin are measured. After oven-aging the sample at 70 °C for 4 hours and after cooling the sample at 23 °C for 1 hour, the dimensions of the test specimens are measured again. Dynamic compression set

[0117] The dynamic compression set is measured according to the method described in NBR 14739 / 10.

[0118] The residual deformation of the ban foam sample is measured immediately after 100,000 cycles of compression / release at 23 °C and after 24 hours. The size of the test specimen being tested is 30 mm × 30 mm × 10 mm, the load on the test specimen is a maximum load of 400 N (90 lb), the disk used has a diameter of 75 mm, and the disk has no inclination.

[0119] The method of dynamic compression permanent set is, in one embodiment, used to quantify the fatigue resistance of foam products. Crosslinked foams containing high levels (e.g., ≧50 phr) of elastomers used in the foamable formulations of the present invention, such as INFUSE™ OBC, have been shown to continue to recover for several days (e.g., 15 days) after the foam has been subjected to testing. Generally, foams made from the foamable formulations of the present invention containing elastomers such as INFUSE™ OBC, which have the advantage of continuing to recover after several days, mean that foam products such as shoe parts (e.g., shoe insoles) made from the compositions or formulations of the present invention are more durable than foam products made from foamable formulations that do not contain the elastomers of the present invention. This is because the foams of the present invention recover their original thickness after compression has been applied to the foam. For example, after running in shoes having insoles made from the foam of the present invention, the insoles recover their original thickness. Bond strength

[0120] The adhesion of the foam article to the transparent flexible PVC sheet is determined using the procedure described in ABNT NBR 10456 / 2020. The bond strength is measured in N / mm in the longitudinal and transverse directions. The visual aspects of bond failure can be observed with the naked eye as, but are not limited to, (1) delamination of the foam from the PVC sheet, (2) detachment of the foam from the PVC sheet, and / or (3) cohesive (foam tearing) failure.

[0121] The bond between the foam specimen with skin and the transparent PVC sheet is evaluated. Bond performance is an important analysis for shoe manufacturers. For example, if the bond of the insole to the upper part of the shoe is insufficient, the entire developed shoe may break even if other characteristics of the shoe are achieved. Insufficient bonding is the resulting type of failure because such a break can occur when the customer is using the shoe.

[0122] The target measured values for hardness and compression set (both static and dynamic) depend on the type of shoe, but generally, the lower the hardness and compression of the foam, the better, and the higher the recovery of the foam, the better.

[0123] In some embodiments, a suitable package of primer / adhesive can be included in the foam product to provide acceptable bonding performance of the foam product.

[0124] Condition the sample (foam specimen) for a minimum period of 24 hours according to Condition A (23 °C ± 2 °C and relative humidity 50% ± 5%) described in ABNT NBR 10455:2021.

[0125] The adhesion process described in the test procedure of ABNT NBR 10456 / 2020 includes the following steps. (1) A step of washing the foam specimen with a special EVA solvent (90SO 270) using a clean cloth. (2) A step of leaving the foam specimen in an oven at 50 °C for 10 minutes. (3) A step of applying an EVA primer (e.g., Kisafix KFPE70SUV) to the specimen using a clean cloth. (4) A step of drying the EVA primer for 10 minutes. (5) A step of washing the transparent PVC sheet with acetone. (6) A step of drying the sheet for 3 to 5 minutes. (7) A step of applying a PU-based adhesive (e.g., Kisafix PVC 180 ST) onto the EVA and the transparent PVC. (8) A step of leaving the adhesive to dry for 20 minutes. (9) A step of reactivating the set at a temperature of 60 °C to 70 °C, and (10) A step of pressing the foam specimen for 15 seconds using a rubber plate to assist in providing a compression of 703 kg / m 2 .

[0126] According to Ibtec, a research institute that conducts joint strength tests, there are several general acceptable ranges for joint strength according to the type of shoes, for example, as follows. (1) For protective, sports, children's, and military shoes: A minimum joint strength of 6.0 N / mm is acceptable. (2) For shoes with medium requirements (for daily use): A joint strength of 4.5 N / mm is acceptable. (3) For dress shoes, high heels, high fashion, and lightweight men: A joint strength of 3.5 N / mm is acceptable. (4) For shoes with low demand (e.g., sandals, slippers, handmade, children's, and infant shoes): A joint strength of 2.5 N / mm is acceptable.

[0127] The values described above are for illustrative purposes and are not a rule or an exhaustive list. The values can vary according to each shoe producer and brand owner. Generally, some foam manufacturers desire a joint strength of at least 2.5 N / mm, which is sufficient for the desired joint performance. Some foam manufacturers consider the visual breakage of the EVA foam sample after subjecting the sample to a joint test to be an indicator of good joint strength. For example, if breakage occurs and the joint strength of the foam is measured to be 2 N / mm, some foam manufacturers consider the occurrence of this visual breakage to be sufficient for manufacturing foam products that are desirable for footwear applications. However, the criteria for the occurrence of the aforementioned visual breakage can vary from foam manufacturer to foam manufacturer. Resilience

[0128] The bounce test method refers to the determination of the elasticity of materials such as foams, expressed as a percentage of the elastic or resilient force of the material. A Schob type pendulum bounce tester or device is used to generate the data for this test, and the procedure used to obtain the bounce measurements is described in DIN 53512. Using a pendulum bounce tester, the resilient force is determined by a free-falling pendulum hammer that falls from a given height, collides with the test specimen of the test, and imparts a certain amount of energy to the test specimen of the test. A portion of that energy is returned to the pendulum by the test specimen and can be measured by the extent to which the pendulum bounces, whereby the restoring force is determined by gravity. The resilient force is the ratio of the returned energy to the applied energy. In a resilient force test, the elasticity is established as the ratio of the height of the pendulum's bounce to the height of the pendulum's fall.

[0129] The pendulum collides with each test specimen 6 times from the pendulum's initial horizontal position. The first 3 collisions serve to mechanically condition the test specimen of the test, and the last 3 collisions serve to establish the resilient force of the test specimen. The median of the last 3 collision measurements is taken as the result of the resilient force of the test specimen. Result Discussion

[0130] The data generated and described in Tables I-IV are data that are normally evaluated in the footwear industry. Some of the properties described above are more important for casual type shoes, while other properties are more important for the insoles of athletic type shoes. Also, the goals for each property of the foam products produced using the foamable composition of the present invention vary according to the intended use of the foam products, and the goals for each property of the foam products vary according to the shoe manufacturer / show brand owner. One object of the present invention is directed to improving the bonding strength of the foam products when bonding the foam products to another different polar substrate such as PVC. However, if the addition of an ethylene-methyl acrylate copolymer to the foamable formulation improves the bonding strength of the foam made from the formulation but reduces other foam properties, that would be undesirable. Therefore, it is highly desirable to improve the bonding strength of the foam made from the formulation while maintaining other foam properties and / or while creating an overall balance of all the foam properties described above.

[0131] Samples containing ELVAX™ 460, 50 phr of INFUSE™ 9500, and 30 phr of ELVALOY™ AC 1330 advantageously showed satisfactory bonding strength (e.g., >2.5 N / mm) and complete delamination of the foam. This formulation sample improved bonding and achieved satisfactory results with respect to density, shrinkage, resilience, and hardness. The compression set properties of the formulation sample were slightly reduced compared to samples containing only ELVAX™ 460 and 50 phr of INFUSE™ 9500. However, by slightly adjusting the level of peroxide in the formulation, higher performance with respect to compression set is achieved (which means that lower compression set is achieved). Using this adjustment for the formulation containing ELVAX™ 460, 50 phr of INFUSE™ 9500, and 30 phr of ELVALOY™ AC 1330, an acceptable compression set is achieved by the formulation and the formulation can be used in more footwear applications.

Claims

1. A foaming composition comprising: (a) at least one elastomer selected from the group consisting of (i) an ethylene / alpha-olefin multi-block interpolymer, (ii) an ethylene / alpha-olefin elastomer, and (iii) combinations thereof; (b) at least one ethylene vinyl acetate; (c) at least one polarity modifier selected from the group consisting of (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) combinations thereof; (d) at least one crosslinking agent; (e) at least one foaming agent.

2. The at least one elastomer, component (a) is (i) an ethylene / alpha-olefin multi-block interpolymer having a density of 0.850 g / cc to 0.890 g / cc and a melt index I of 0.5 g / 10 min to 50 g / 10 min ２ an ethylene / alpha-olefin elastomer having a density of 0.850 g / cc to 0.890 g / cc and a melt index I of 0.5 g / 10 min to 50 g / 10 min ２ and is selected from the group consisting of (iii) combinations thereof The at least one ethylene vinyl acetate, component (b), is ethylene vinyl acetate having a vinyl acetate level of 18 wt% to 35 wt%; The at least one polarity modifier, component (c), is selected from the group consisting of (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) combinations thereof; The at least one crosslinking agent, component (d), is selected from the group consisting of dicumyl peroxide and mixtures of dicumyl peroxide with other crosslinking agents; The at least one foaming agent, component (e), is selected from the group consisting of azodicarbonamide and mixtures of azodicarbonamide with other foaming agents and / or physical blowing agents. The foaming composition according to claim 1.

3. The composition according to claim 1, further comprising one or more compounds selected from the group consisting of (f) (i) an accelerator, (ii) a filler, and (iii) combinations thereof.

4. The accelerator is ZnO, ZnSt, or a mixture thereof, and the filler is CaCO ３ , TiO ２ , or a mixture thereof. The foaming composition according to claim 3.

5. The ethylene / alpha-olefin multi-block interpolymer has the following characteristics: a density of 0.850 g / cc to 0.890 g / cc and a melt index I of 0.5 g / 10 min to 50 g / 10 min ２ The foaming composition according to claim 1, having one or more of the above. ２

6. The concentration of the elastomer in the composition is 45 wt% or more, the concentration of the ethylene vinyl acetate in the composition is 10 wt% to 35 wt%, the concentration of the at least one polarity modifier in the composition is 10 wt% to 40 wt%, the concentration of the crosslinking agent in the composition is 1 wt% or more, and the concentration of the foaming agent in the composition is 1 wt% or more. The above concentrations are based on all the components in the foaming composition. The foaming composition according to claim 1.

7. A process for producing a foaming composition, comprising: (a) at least one elastomer selected from the group consisting of (i) an ethylene / alpha-olefin multi-block interpolymer, (ii) an ethylene / alpha-olefin elastomer, and (iii) combinations thereof; (b) at least one ethylene vinyl acetate; (c) at least one polarity modifier selected from the group consisting of (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) combinations thereof; (d) at least one crosslinking agent; (e) at least one foaming agent, and mixing them. A process for producing a foaming composition.

8. A foam article formed from the composition according to any one of claims 1 to 7.

9. The foam article according to claim 8, wherein the foam article exhibits one or more of the following properties: a bonding strength of 1 N / mm to 5 N / mm, a compression set of 15 percent to 60 percent, a shrinkage of 0 percent to 2 percent, a hardness of 25 Shore A to 50 Shore A, and a resilience of 40 percent to 60 percent.

10. The foam article according to claim 8, wherein the foam article is a shoe part.

11. A process for manufacturing a foam article, comprising: (I) Providing components: (a) at least one elastomer selected from the group consisting of (i) an ethylene / alpha-olefin multi-block interpolymer, (ii) an ethylene / alpha-olefin elastomer, and (iii) combinations thereof; (b) at least one ethylene vinyl acetate; (c) at least one polarity modifier selected from the group consisting of (i) an ethylene-alkyl acrylate copolymer, (ii) an ethylene-alkyl methacrylate copolymer, and (iii) combinations thereof; (d) at least one crosslinking agent; (e) at least one foaming agent; (II) Mixing the components (a) to (e) in step (I) at a temperature of 120°C to 130°C to form a foaming composition. (III) At least one foam article from the foaming composition of step (II), wherein the foam article has the following properties: a bonding strength of 1 N / mm to 5 N / mm, a compression set of 15 percent to 60 percent, a shrinkage of 0.001 percent to 2 percent, a hardness of 25 Shore A to 50 Shore A, and a resilience of 40 percent to 60 percent, forming a foam article that exhibits one or more of these properties, and a process comprising the steps of: **Claim 12** The process according to claim 11, wherein the foam article is at least one foam layer included in a multilayer structure, the foam layer is bonded to a polar material layer, and when the multilayer structure is subjected to a bonding strength test, visual delamination of the foam layer occurs.

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