WO2021076090A1 - Compositions et procédés de fabrication de mousses thermodurcissables pour semelles de chaussures - Google Patents

Compositions et procédés de fabrication de mousses thermodurcissables pour semelles de chaussures Download PDF

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Publication number
WO2021076090A1
WO2021076090A1 PCT/US2019/056016 US2019056016W WO2021076090A1 WO 2021076090 A1 WO2021076090 A1 WO 2021076090A1 US 2019056016 W US2019056016 W US 2019056016W WO 2021076090 A1 WO2021076090 A1 WO 2021076090A1
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WIPO (PCT)
Prior art keywords
silane
polyolefin elastomer
polyolefin
crosslinked foam
grafted
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Application number
PCT/US2019/056016
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English (en)
Inventor
Krishnamachari Gopalan
Original Assignee
Cooper-Standard Automotive Inc.
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Publication date
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Priority to PCT/US2019/056016 priority Critical patent/WO2021076090A1/fr
Publication of WO2021076090A1 publication Critical patent/WO2021076090A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/10—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing nitrogen, the blowing agent being a compound containing a nitrogen-to-nitrogen bond
    • C08J9/102—Azo-compounds
    • C08J9/103—Azodicarbonamide
    • A—HUMAN NECESSITIES
    • A43—FOOTWEAR
    • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
    • A43B13/00—Soles; Sole-and-heel integral units
    • A43B13/02—Soles; Sole-and-heel integral units characterised by the material
    • A43B13/04—Plastics, rubber or vulcanised fibre
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D35/00—Producing footwear
    • B29D35/0009—Producing footwear by injection moulding; Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D35/00—Producing footwear
    • B29D35/0054—Producing footwear by compression moulding, vulcanising or the like; Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D35/00—Producing footwear
    • B29D35/12—Producing parts thereof, e.g. soles, heels, uppers, by a moulding technique
    • B29D35/122—Soles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/122—Hydrogen, oxygen, CO2, nitrogen or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/32—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof from compositions containing microballoons, e.g. syntactic foams
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
    • C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/02—Foams characterised by the foaming process characterised by mechanical pre- or post-treatments
    • C08J2201/026—Crosslinking before of after foaming
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/04—N2 releasing, ex azodicarbonamide or nitroso compound
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/06—CO2, N2 or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/08—Supercritical fluid
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/22—Expandable microspheres, e.g. Expancel®
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2423/04—Homopolymers or copolymers of ethene
    • C08J2423/08—Copolymers of ethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2431/00—Characterised by the use of copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, or carbonic acid, or of a haloformic acid
    • C08J2431/02—Characterised by the use of omopolymers or copolymers of esters of monocarboxylic acids
    • C08J2431/04—Homopolymers or copolymers of vinyl acetate

Definitions

  • the present invention generally relates to polymer compositions that may be used to form shoe soles, and more particularly, to crosslinked foam polyolefin elastomers compositions used to form both midsoles and/or outsoles and dual crosslinking/self- catalyzed methods for manufacturing these shoe soles and compositions.
  • Shoe soles have been traditionally made of natural and synthetic rubbers.
  • the use of sponge soles has been on the rise to keep pace with the increasing demand for lightweight and functional sport shoes and dress shoes alike.
  • Many different synthetic materials used for sponge soles are known including ethylene vinyl acetate (EVA), polyurethanes (PU), and nitrile rubbers.
  • EVA sponges account for the largest market share of sponge sole materials used to form midsoles, outsoles, and aftermarket insoles using techniques that include press foaming and injection foaming processes.
  • the material will need to satisfy a variety of material property requirements based on its end use shoe application, such as density, rebound, grip on various types of surfaces, wear resistance, processability, and/or shock absorbance. From shoes of athletes to the elderly, the sole of the shoe must provide superior comfort, traction, and durability.
  • a footwear article includes a shoe sole.
  • the shoe sole includes a crosslinked foam polyolefin elastomer having a density less than 0.88 g/cm 3 .
  • the crosslinked foam polyolefin elastomer includes: a silane-grafted polyolefin elastomer, a silane-grafted olefin block copolymer, a polyolefin elastomer (POE), an olefin block copolymer (OBC), or a combination thereof; an ethylene vinyl acetate (EVA) copolymer; a crosslinker; a condensation catalyst; and a foaming agent.
  • the shoe sole exhibits a compression set of from about 1.0 % to about 50.0 %, as measured according to ASTM D 395 (48 hrs @ 50 °C).
  • a crosslinked foam polyolefin elastomer composition includes a silane-grafted polyolefin having a density less than 0.86 g/cm 3 , a crosslinker, a condensation catalyst, and a foaming agent.
  • the crosslinked foam polyolefin elastomer composition exhibits a compression set of from about 1.0 % to about 50.0 %, as measured according to ASTM D 395 (48 hrs @ 50 °C) and has a density less than 0.88 g/cm 3 .
  • a method for making a shoe sole includes extruding a silane-grafted polyolefin, an ethylene vinyl acetate (EVA) copolymer, a crosslinker, a foaming agent, and a condensation catalyst together to form a crosslinkable polyolefin blend; injection molding the crosslinkable polyolefin blend into a shoe sole element; crosslinking the crosslinkable polyolefin blend of the shoe sole element using a dual crosslinking system to form silane graft-silane graft crosslinks and carbon-carbon crosslinks at a temperature greater than 150 °C to form a shoe sole having a density less than 0.50 g/cm 3 ; and catalyzing the dual crosslinking system of the crosslinking step by generating acetic acid in situ from the ethylene vinyl acetate (EVA) copolymer.
  • the shoe sole exhibits a compression set of from about 1.0 % to
  • FIG. 1 is a perspective view of a shoe according to some aspects of the present disclosure
  • FIG. 2 is a cross-sectional perspective view of the shoe depicted in FIG. 1 according to some aspects of the present disclosure
  • FIG. 3 is a flow diagram of a method for making a shoe sole according to some aspects of the present disclosure
  • FIG. 4 is a schematic view of a method for making a shoe sole using a crosslinked foam polyolefin elastomer and an injection molding approach according to some aspects of the present disclosure
  • FIG. 5 is a schematic cross-sectional view of a compression mold according to some aspects of the present disclosure.
  • FIG. 6 is a schematic cross-sectional view of an injection mold according to some aspects of the present disclosure.
  • FIG. 7 is a schematic cross-sectional view of an injection compression mold according to some aspects of the present disclosure.
  • FIG. 8 is a schematic cross-sectional view of an extruder equipped with a supercritical fluid injector according to some aspects of the present disclosure
  • FIG. 9 is a resilience versus specific gravity plot for a variety of crosslinked materials according to some aspects of the present disclosure.
  • FIG. 10 is a hardness versus specific gravity plot for a variety of crosslinked materials according to some aspects of the present disclosure
  • FIG. 11 is a micrograph of a cross-sectioned midsole formed using a supercritical fluid foaming process according to some aspects of the present disclosure
  • FIG. 12 is a series of micrographs taken from a cross-sectioned midsole formed using a chemical foaming agent according to some aspects of the present disclosure
  • FIG. 13 is a micrograph of a cross-sectioned midsole formed using a high density silane-graft polyolefin and a chemical blowing agent according to some aspects of the present disclosure
  • FIG. 14 is a micrograph of a cross-sectioned midsole formed using a low density silane-graft polyolefin and a chemical blowing agent according to some aspects of the present disclosure.
  • FIG. 15 is a static compression plot providing compressive strength versus compressive strain for a variety of commercially available shoe soles according to some aspects of the present disclosure
  • FIG. 16 is a static compression plot providing compressive strength versus compressive strain for a variety of crosslinked foamed polyolefin elastomers according to some aspects of the present disclosure
  • FIG. 17 is a static compression plot providing compressive strength versus compressive strain for a variety of crosslinked foamed polyolefin elastomers according to some aspects of the present disclosure
  • FIG. 18 is a load versus position plot of an inventive crosslinked foamed polyolefin elastomers according to some aspects of the present disclosure
  • FIG. 19 is a graph depicting volume loss over 1000 cycles for a variety of crosslinked foamed polyolefin elastomers according to some aspects of the present disclosure.
  • FIG. 20 is a graph illustrating the compression set of an inventive crosslinked foamed polyolefin elastomer as plotted with respect to temperatures ranging from 100 °C to 150 °C.
  • a value modified by a term or terms, such as “about” and “substantially,” may not be limited to the precise value specified.
  • the approximating language may correspond to the precision of an instrument for measuring the value.
  • the modifier “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4" also discloses the range “from 2 to 4.”
  • the term "and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed.
  • the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.
  • the footwear article may include a shoe sole including, for example, a show outsole and/or a shoe midsole.
  • the shoe sole, shoe outsole, and/or shoe midsole includes a crosslinked foam polyolefin elastomer having a density less than 0.88 g/cm 3 .
  • the crosslinked foam polyolefin elastomer includes a silane-grafted polyolefin elastomer, a silane-grafted olefin block copolymer, a polyolefin elastomer (POE), an olefin block copolymer (OBC), or a combination thereof.
  • the crosslinked foam polyolefin elastomer additionally includes an ethylene vinyl acetate (EVA) copolymer, a crosslinker, a condensation catalyst, and a foaming agent.
  • EVA ethylene vinyl acetate
  • Each of the shoe sole and shoe midsole exhibits a compression set of from about 1.0 % to about 50.0 %, as measured according to ASTM D 395 (48 hrs @ 50 °C).
  • FIG. 1 a perspective view of a shoe 10 is provided.
  • the shoe 10 includes an outsole 14 coupled to a midsole 18 where the midsole 18 is positioned directly above the outsole 14.
  • a toe box 22 makes up a front portion of the shoe 10 in combination with a toe cap 26.
  • the toe box 22 and toe cap 26 are positioned to support and enclose toes of a foot.
  • a tongue 30 works in combination with uppers 34 to support the top of the foot.
  • a collar 38 and a heal counter 42 are positioned at a rear of the shoe 10 and work together to comfortably position and retain a heel in the shoe 10.
  • FIG. 1 is a running shoe, the shoe 10 is not meant to be limiting and the shoe 10 could additionally include, for example, other athletic shoes, sandals, hiking boots, winter boots, dress shoes, and medical orthotic shoes.
  • FIG. 2 a cross-sectional view of the shoe 10 depicted in FIG. 1 is provided.
  • This cross-sectional view provides the respective thickness of the outsole 14 compared to the midsole 18.
  • the midsole 18 is the part of the shoe 10 that is sandwiched between the outsole 14 and an instep liner 46 that provides cushioning and rebound, while helping protect the foot from feeling hard or sharp objects.
  • the foot is in contact with a sock liner 50 that is positioned as a top layer on the instep liner 46 while the foot's positioning in the interior of the shoe 10 is maintained with the toe box 22, tongue 30, and uppers 34.
  • Midsoles 18 provide stability for the foot, necessitating that the material used to fabricate the midsole 18 be designed to endure all types of challenges typical of foot wear - i.e., terrain, the user's weight, and pressure sources incurred during walking or running, etc.
  • the most common materials used in the manufacture of midsoles are the expanded foam rubber version forms of ethylene vinyl acetate (EVA). Like most rubbers, EVA is soft and flexible, but it is also easy to process and manipulate in the manufacturing of versatile articles (midsoles included) due to its thermoplastic properties.
  • EVA ethylene vinyl acetate
  • EVA is typically selected as the desired material to produce midsoles because of its "low-temperature" toughness, stress-crack resistance, waterproof properties, and resistance to UV-radiation
  • the biggest critique against EVA is its short life. Over time, EVA tends to compress and users (runners especially) say that they feel their shoes go flat after a period of time.
  • the only way to avoid this flattening of the EVA midsole is to replace one's shoes every 3 to 6 months.
  • EVA As an alternative to EVA, disclosed herein is a family of crosslinked foam polyolefin elastomers.
  • the elastomers of the disclosure provide many of the same advantages as EVA, but they also offer many improved material properties including, for example, density, rebound, compression set, and durability.
  • the crosslinked foam polyolefin elastomers, and the variety of techniques used to mold shoe soles disclosed herein, produce lightweight materials containing thousands of tiny bubbles that provide cushioning and shock absorption to users.
  • One of the properties that makes the disclosed crosslinked foam polyolefin elastomers better than EVA and other conventional shoe sole materials is the relative lightness of these elastomers.
  • the crosslinked foam polyolefin elastomers have a low density, making them ideal materials used in footwear where weight is an issue.
  • the disclosure herein focuses on the composition, method of making the composition, and the corresponding material properties for the crosslinked foam polyolefin elastomers used to make shoe soles, for example, outsoles 14 and midsoles 18.
  • the shoe sole can be formed from a silane-grafted polyolefin where the silane-grafted polyolefin may have a catalyst added to form a silane-crosslinkable polyolefin elastomer.
  • the crosslinked foam polyolefin elastomers or blend includes the silane-grafted polyolefin having a density less than 0.86g/cm 3 , an ethylene vinyl acetate (EVA) copolymer, a crosslinker, a condensation catalyst, and a foaming agent.
  • EVA ethylene vinyl acetate
  • the disclosure herein additionally focuses on silane-grafted polyolefin elastomers, silane-grafted olefin block copolymers, or silane grafted blends of polyolefin elastomers (POEs) and olefin block copolymers (OBCs) dry mixed with an ethylene vinyl acetate (EVA) copolymer material including at least one peroxide, at least one blowing agent, and/or at least one tin or acid based condensation catalyst.
  • EVA ethylene vinyl acetate copolymer material
  • An injection molding system can then melt and activate this corresponding dry mix to form a dual crosslinking system.
  • This dual crosslinking system can provide both silane graft-silane graft crosslinks and carbon-carbon crosslinks along the hydrocarbon backbone.
  • the incorporation of both silane graft-silane graft and carbon-carbon backbone crosslinks can afford foamed articles that provide exceptional material properties including compression set, rebound resilience, and hardness levels that are ideal for footwear applications.
  • the silane-grafted polyolefin may include a silane-grafted polyolefin elastomer, a silane-grafted olefin block copolymer, a polyolefin elastomer (POE), an olefin block copolymer (OBC), or a combination thereof.
  • silane-grafted polyolefin elastomer, silane-grafted olefin block copolymer, polyolefin elastomer (POE), and olefin block copolymer (OBC) materials may be formed using at least one polyolefin.
  • the at least one polyolefin can be a polyolefin elastomer including an olefin block copolymer, an ethylene/a-olefin copolymer, a propylene/a-olefin copolymer, EPDM, EPM, or a mixture of two or more of any of these materials.
  • Exemplary block copolymers include those sold under the trade names INFUSETM, an olefin block co-polymer (the Dow Chemical Company) and SEPTONTM V-SERIES, a styrene-ethylene-butylene-styrene block copolymer (Kuraray Co., LTD.).
  • Exemplary ethylene/a-olefin copolymers include those sold under the trade names TAFMERTM (e.g., TAFMER DF710) (Mitsui Chemicals, Inc.), and ENGAGETM (e.g., ENGAGE 8150) (the Dow Chemical Company).
  • Exemplary propylene/a-olefin copolymers include those sold under the trade name VISTAMAXXTM 6102 grades (Exxon Mobil Chemical Company), TAFMERTM XM (Mitsui Chemical Company), and VERSIFYTM (Dow Chemical Company).
  • the EPDM may have a diene content of from about 0.5 to about 10 wt %.
  • the EPM may have an ethylene content of 45 wt % to 75 wt %.
  • ком ⁇ онент refers to olefin comonomers which are suitable for being polymerized with olefin monomers, such as ethylene or propylene monomers.
  • Comonomers may comprise but are not limited to aliphatic C 2 -C 20 a-olefins.
  • suitable aliphatic C 2 -C 2 o a-olefins include ethylene, propylene, 1-butene, 4-methyl-l- pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1- octadecene and 1-eicosene.
  • the comonomer is vinyl acetate.
  • copolymer refers to a polymer, which is made by linking more than one type of monomer in the same polymer chain.
  • the term "homopolymer” refers to a polymer which is made by linking olefin monomers, in the absence of comonomers.
  • the amount of comonomer can, in some embodiments, be from greater than 0 wt % to about 12 wt % based on the weight of the polyolefin, including from greater than 0 wt % to about 9 wt %, and from greater than 0 wt % to about 7 wt %.
  • the comonomer content is greater than about 2 mol % of the final polymer, including greater than about 3 mol % and greater than about 6 mol %.
  • the comonomer content may be less than or equal to about 30 mol %.
  • a copolymer can be a random or block (heterophasic) copolymer.
  • the polyolefin is a random copolymer of propylene and ethylene.
  • the at least one polyolefin is selected from the group consisting of: an olefin homopolymer, a blend of homopolymers, a copolymer made using two or more olefins, a blend of copolymers each made using two or more olefins, and a combination of olefin homopolymers blended with copolymers made using two or more olefins.
  • the olefin may be selected from ethylene, propylene, 1-butene, 1- propene, 1-hexene, 1-octene, and other higher 1-olefin.
  • the at least one polyolefin may be synthesized using many different processes (e.g., using gas phase and solution based metallocene catalysis and Ziegler-Natta catalysis) and optionally using a catalyst suitable for polymerizing ethylene and/or a-olefins.
  • a metallocene catalyst may be used to produce low density ethylene/a- olefin polymers.
  • the polyethylene used for the at least one polyolefin can be classified into several types including, but not limited to, LDPE (Low Density Polyethylene), LLDPE (Linear Low Density Polyethylene), and HDPE (High Density Polyethylene).
  • the polyethylene can be classified as Ultra High Molecular Weight (UHMW), High Molecular Weight (HMW), Medium Molecular Weight (MMW) and Low Molecular Weight (LMW).
  • the polyethylene may be an ultra-low density ethylene elastomer.
  • the at least one polyolefin may include a LDPE/silane copolymer or blend.
  • the at least one polyolefin may be polyethylene that can be produced using any catalyst known in the art including, but not limited to, chromium catalysts, Ziegler-Natta catalysts, metallocene catalysts or post-metallocene catalysts.
  • the at least one polyolefin may have a molecular weight distribution M w /M n of less than or equal to about 5, less than or equal to about 4, from about 1 to about 3.5, or from about 1 to about 3.
  • the at least one polyolefin may be present in an amount of from greater than 0 wt % to about 100 wt % of the composition. In some embodiments, the amount of polyolefin elastomer is from about 30 wt % to about 70 wt %. In some aspects, the at least one polyolefin fed to an extruder can include from about 50 wt % to about 80 wt % of an ethylene/a-olefin copolymer, including from about 60 wt % to about 75 wt % and from about 62 wt % to about 72 wt %.
  • the at least one polyolefin may have a melt viscosity in the range of from about 2,000 cP to about 50,000 cP as measured using a Brookfield viscometer at a temperature of about 177 °C.
  • the melt viscosity is from about 4,000 cP to about 40,000 cP, including from about 5,000 cP to about 30,000 cP and from about 6,000 cP to about 18,000 cP.
  • the at least one polyolefin may have a melt index (T2), measured at 190 °C under a
  • the at least one polyolefin has a fractional melt index of from 0.5 g/10 min to about 3,500 g/10 min.
  • the density of the at least one polyolefin is less than about 0.90 g/cm 3 , less than about 0.89 g/cm 3 , less than about 0.88 g/cm 3 , less than about 0.87 g/cm 3 , less than about 0.86 g/cm 3 , less than about 0.85 g/cm 3 , less than about 0.84 g/cm 3 , less than about 0.83 g/cm 3 , less than about 0.82 g/cm 3 , less than about 0.81 g/cm 3 , or less than about 0.80 g/cm 3 .
  • the density of the at least one polyolefin may be from about 0.85 g/cm 3 to about 0.89 g/cm 3 , from about 0.85 g/cm 3 to about 0.88 g/cm 3 , from about 0.84 g/cm 3 to about 0.88 g/cm 3 , or from about 0.83 g/cm 3 to about 0.87 g/cm 3 .
  • the density is at about 0.84 g/cm 3 , about 0.85 g/cm 3 , about 0.86 g/cm 3 , about 0.87 g/cm 3 , about 0.88 g/cm 3 , or about 0.89 g/cm 3 .
  • the percent crystallinity of the at least one polyolefin may be less than about 60 %, less than about 50 %, less than about 40 %, less than about 35 %, less than about 30 %, less than about 25 %, or less than about 20 %.
  • the percent crystallinity may be at least about 10 %. In some aspects, the crystallinity is in the range of from about 2 % to about 60 %.
  • the crosslinked foam polyolefin elastomers or blend may include two or more polyolefins.
  • more than one polyolefin is generally used to modify the hardness and/or processability of the first polyolefin, which has a density less than 0.90 g/cm 3 .
  • more than just the first and second polyolefins may be used to form the crosslinked foam polyolefin elastomers or blend.
  • one, two, three, four, or more different polyolefins having a density less than 0.90 g/cm 3 , less than 0.89 g/cm 3 , less than 0.88 g/cm 3 , less than 0.87 g/cm 3 , less than 0.86 g/cm 3 , or less than 0.85 g/cm 3 may be substituted and/or used for the first polyolefin.
  • one, two, three, four, or more different polyolefins, polyethylene-co-propylene copolymers may be substituted and/or used for the second polyolefin.
  • the first and second polyolefins may further include one or more
  • TPVs and/or EPDM with or without silane graft moieties where the TPV and/or EPDM polymers are present in an amount of up to 20 wt % of the silane-crosslinked polyolefin elastomer/blend.
  • the grafting initiator (also referred to as "a radical initiator” in the disclosure) can be utilized in the grafting process of at least one polyolefin by reacting with the respective polyolefin to form a reactive species that can react and/or couple with the silane crosslinker molecule.
  • the grafting initiator can include halogen molecules, azo compounds (e.g., azobisisobutyl), carboxylic peroxyacids, peroxyesters, peroxyketals, and peroxides (e.g., alkyl hydroperoxides, dialkyl peroxides, and diacyl peroxides).
  • the grafting initiator is an organic peroxide selected from di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butyl- peroxy)hexyne-3, l,3-bis(t-butyl- peroxy-isopropyl)benzene, n-butyl-4,4-bis(t-butyl- peroxy)valerate, benzoyl peroxide, t- butylperoxybenzoate, t-butylperoxy isopropyl carbonate, and t-butylperbenzoate, as well as bis(2-methylbenzoyl)peroxide, bis(4- methylbenzoyl)peroxide, t-butyl peroctoate, cumene hydroperoxide, methyl ethyl ketone peroxide, lauryl peroxide, tert-but
  • the grafting initiator is present in an amount of from greater than 0 wt % to about 2 wt % of the composition, including from about 0.15 wt % to about 1.2 wt % of the composition.
  • the amount of initiator and silane employed may affect the final structure of the silane grafted polymer (e.g., the degree of grafting in the grafted polymer and the degree of crosslinking in the cured polymer).
  • the reactive composition contains at least 100 ppm of initiator, or at least 300 ppm of initiator.
  • the initiator may be present in an amount from 300 ppm to 1500 ppm or from 300 ppm to 2000 ppm.
  • the silane:initiator weight ratio may be from about 20:1 to about 400:1, including from about 30:1 to about 400:1, from about 48:1 to about 350:1, and from about 55:1 to about 333:1.
  • the grafting reaction can be performed under conditions that optimize grafts onto the interpolymer backbone while minimizing side reactions (e.g., the homopolymerization of the grafting agent).
  • the grafting reaction may be performed in a melt, in solution, in a solid-state, and/or in a swollen-state.
  • the silanation may be performed in a wide-variety of equipment (e.g., twin screw extruders, single screw extruders, Brabenders, internal mixers such as Banbury mixers, and batch reactors).
  • the polyolefin, silane, and initiator are mixed in the first stage of an extruder.
  • the melt temperature i.e., the temperature at which the polymer starts melting and begins to flow
  • the melt temperature may be from about 120 °C to about 260 °C, including from about 130 °C to about 250 °C.
  • a silane crosslinker can be used to covalently graft silane moieties onto the at least one polyolefin and the silane crosslinker may include alkoxysilanes, silazanes, siloxanes, or a combination thereof.
  • the grafting and/or coupling of the various potential silane crosslinkers or silane crosslinker molecules is facilitated by the reactive species formed by the grafting initiator reacting with the respective silane crosslinker.
  • the silane crosslinker is a silazane where the silazane may include, for example, hexamethyldisilazane (HMDS) or bis(trimethylsilyl)amine.
  • the silane crosslinker is a siloxane where the siloxane may include, for example, polydimethylsiloxane (PDMS) and octamethylcyclotetrasiloxane.
  • the silane crosslinker is an alkoxysilane.
  • the term silane crosslinker is an alkoxysilane.
  • alkoxysilane refers to a compound that comprises a silicon atom, at least one alkoxy group and at least one other organic group, wherein the silicon atom is bonded with the organic group by a covalent bond.
  • the alkoxysilane is selected from alkylsilanes; acryl-based silanes; vinyl-based silanes; aromatic silanes; epoxy-based silanes; amino-based silanes and amines that possess -NH 2 , -NHCH 3 or -N(CH 3 ) 2 ; ureide-based silanes; mercapto- based silanes; and alkoxysilanes which have a hydroxyl group (i.e., -OH).
  • An acryl-based silane may be selected from the group comprising beta-acryloxyethyl trimethoxysilane; beta-acryloxy propyl trimethoxysilane; gamma- acryloxyethyl trimethoxysilane; gamma- acryloxypropyl trimethoxysilane; beta- acryloxyethyl triethoxysilane; beta-acryloxypropyl triethoxysilane; gamma-acryloxyethyl triethoxysilane; gamma-acryloxypropyl triethoxysilane; beta-methacryloxyethyl trimethoxysilane; beta-methacryloxypropyl trimethoxysilane; gamma-methacryloxyethyl trimethoxysilane; gamma-methacryloxypropyl trimethoxysilane; beta-methacryloxyethyl trimethoxysilane; beta-methacryloxy
  • a vinyl-based silane may be selected from the group comprising vinyl trimethoxysilane; vinyl triethoxysilane; p-styryl trimethoxysilane, methylvinyldimethoxysilane, vinyldimethylmethoxysilane, divinyldimethoxysilane, vinyltris(2-methoxyethoxy)silane, and vinylbenzylethylenediaminopropyltrimethoxysilane.
  • An aromatic silane may be selected from phenyltrimethoxysilane and phenyltriethoxysilane.
  • An epoxy-based silane may be selected from the group comprising 3-glycydoxypropyl trimethoxysilane; 3- glycydoxypropylmethyl diethoxysilane; 3-glycydoxypropyl triethoxysilane; 2-(3,4- epoxycyclohexyl)ethyl trimethoxysilane, and glycidyloxypropylmethyldimethoxysilane.
  • An amino-based silane may be selected from the group comprising 3-aminopropyl triethoxysilane; 3-aminopropyl trimethoxysilane; 3-aminopropyldimethyl ethoxysilane; 3- aminopropylmethyldiethoxysilane; 4-aminobutyltriethoxysilane; 3- aminopropyldiisopropyl ethoxysilane; l-amino-2-(dimethylethoxysilyl)propane; (aminoethylamino)-3- isobutyldimethyl methoxysilane; N-(2-aminoethyl)-3- aminoisobutylmethyl dimethoxysilane; (aminoethylaminomethyl)phenetyl trimethoxysilane; N-(2-aminoethyl)-3- aminopropylmethyl dimethoxysilane; N-(2- aminoethyl)-3-
  • An ureide-based silane may be 3- ureidepropyl triethoxysilane.
  • a mercapto-based silane may be selected from the group comprising 3-mercaptopropylmethyl dimethoxysilane, 3-mercaptopropyl trimethoxysilane,
  • An alkoxysilane having a hydroxyl group may be selected from the group comprising hydroxymethyl triethoxysilane; N-(hydroxyethyl)-N- methylaminopropyl trimethoxysilane; bis(2- hydroxyethyl)-3-aminopropyl triethoxysilane; N-(3-triethoxysilylpropyl)-4-hydroxy butylamide; l,l-(triethoxysilyl)undecanol; triethoxysilyl undecanol; ethylene glycol acetal; and N-(3-ethoxysilylpropyl)gluconamide.
  • the alkylsilane may be expressed with a general formula: R n Si(OR') 4- n wherein: n is 1 , 2 or 3; R is a Ci-20 alkyl or a C2-20 alkenyl; and R' is an Ci-20 alkyl.
  • R n Si(OR') 4- n wherein: n is 1 , 2 or 3; R is a Ci-20 alkyl or a C2-20 alkenyl; and R' is an Ci-20 alkyl.
  • alkyl by itself or as part of another substituent, refers to a straight, branched or cyclic saturated hydrocarbon group joined by single carbon- carbon bonds having 1 to 20 carbon atoms, for example 1 to 10 carbon atoms, for example 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms.
  • Ci_ 6 alkyl means an alkyl of one to six carbon atoms.
  • alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, f-butyl, 2-methylbutyl, pentyl, iso amyl and its isomers, hexyl and its isomers, heptyl and its isomers, octyl and its isomer, decyl and its isomer, dodecyl and its isomers.
  • C2-20 alkenyl by itself or as part of another substituent, refers to an unsaturated hydrocarbyl group, which may be linear, or branched, comprising one or more carbon-carbon double bonds having 2 to 20 carbon atoms.
  • Examples of C2-6 alkenyl groups are ethenyl, 2-propenyl, 2-butenyl, 3-butenyl, 2- pentenyl and its isomers, 2-hexenyl and its isomers, 2,4-pentadienyl and the like.
  • the alkylsilane may be selected from the group comprising methyltrimethoxysilane; methyltriethoxysilane; ethyltrimethoxysilane; ethyltriethoxysilane; propyltrimethoxysilane; propyltriethoxysilane; hexyltrimethoxysilane; hexyltriethoxysilane; octyltrimethoxysilane; octyltriethoxysilane; decyltrimethoxysilane; decyltriethoxysilane; dodecyltrimethoxysilane: dodecyltriethoxysilane; tridecyltrimethoxysilane; dodecyltriethoxysilane; hexadecyltrimethoxysilane; hexadecyltriethoxysilane; o
  • the alkylsilane compound may be selected from triethoxyoctylsilane, trimethoxyoctylsilane, and a combination thereof.
  • the silane crosslinker can include, but is not limited to, unsaturated silanes which include an ethylenically unsaturated hydrocarbyl group (e.g., a vinyl, allyl, isopropenyl, butenyl, cyclohexenyl or a gamma-(meth)acryloxy allyl group) and a hydrolyzable group (e.g., a hydrocarbyloxy, hydrocarbonyloxy, or hydrocarbylamino group).
  • unsaturated silanes which include an ethylenically unsaturated hydrocarbyl group (e.g., a vinyl, allyl, isopropenyl, butenyl, cyclohexenyl or a gamma-(meth)acryloxy allyl group) and a hydrolyzable group (e.g., a hydrocarbyloxy, hydrocarbonyloxy, or hydrocarbylamino group).
  • Non-limiting examples of hydrolyzable groups include, but are not limited to, methoxy, ethoxy, formyloxy, acetoxy, proprionyloxy, and alkyl, or arylamino groups.
  • the silane crosslinkers are unsaturated alkoxy silanes which can be grafted onto the polymer.
  • additional exemplary silane crosslinkers include vinyltrimethoxysilane, vinyltriethoxysilane, 3-(trimethoxysilyl)propyl methacrylate gamma-(meth)acryloxypropyl trimethoxysilane), and mixtures thereof.
  • the silane crosslinker may be present in the silane-grafted polyolefin elastomer in an amount of from greater than 0 wt % to about 10 wt %, including from about 0.5 wt % to about 5 wt %.
  • the amount of silane crosslinker may be varied based on the nature of the olefin polymer, the silane itself, the processing conditions, the grafting efficiency, the application, and other factors.
  • the amount of silane crosslinker may be at least 2 wt %, including at least 4 wt % or at least 5 wt %, based on the weight of the reactive composition.
  • the amount of silane crosslinker may be at least 10 wt %, based on the weight of the reactive composition.
  • the silane crosslinker content is at least 1% based on the weight of the reactive composition.
  • the silane crosslinker fed to the extruder may include from about 0.5 wt % to about 10 wt % of silane monomer, from about 1 wt % to about 5 wt % silane monomer, or from about 2 wt % to about 4 wt % silane monomer.
  • EVA Ethylene Vinyl Acetate
  • the ethylene vinyl acetate (EVA) copolymer may include a variety of different structures and monomer content to provide the desired catalyst activity and/or final material properties for the crosslinked foam polyolefin elastomer.
  • the EVA copolymer may be an alternating copolymer, a block copolymer, a random copolymer, an AB block copolymer, an ABA block copolymer, or an ABABA copolymer.
  • vinyl acetate may be polymerized using any catalyst or polymerization system known in the art to form a block or random copolymer with ethylene, propylene, 1-butene, 1-propene, 1-hexene, 1-octene, and higher and lower a-olefins.
  • the amount of vinyl acetate present in the EVA or other vinyl acetate-co-a-olefin copolymer may be from greater than 0 wt % to about 75 wt %, from greater than 0 wt % to about 50 wt %, from greater than 0 wt % to about 25 wt %, from about 5 wt % to about 25 wt %, from about 10 wt % to about 25 wt %, from about 10 wt % to about 66 wt %, from about 25 wt % to about 50 wt %, from about 15 wt % to about 35 wt %, and from about 25 wt % to about 75 wt %.
  • the vinyl acetate monomer content is greater than about 2 mol % of the final polymer, greater than about 3 mol %, greater than about 6 mol %, greater than about 10 mol % of the final polymer, greater than about 15 mol %, greater than about 20 mol %, greater than about 25 mol %, greater than about 35 mol %, less than about 2 mol % of the final polymer, less than about 3 mol %, less than about 6 mol %, less than about 10 mol % of the final polymer, less than about 15 mol %, less than about 20 mol %, less than about 25 mol %, or less than about 35 mol % of the final EVA polymer or other vinyl acetate-co-a-olefin copolymer.
  • the comonomer content may be less than or equal to about 30 mol %.
  • the EVA copolymer and/or alternative vinyl acetate-co-a-olefin copolymer provide a catalytic effect to the crosslinking reaction of silane grafts to silane grafts, silane grafts to the carbon backbone, and carbon to carbon along the polymer backbones.
  • the acetate functionality positioned along the respective polymer backbone is in equilibrium between the associated acetate group bound to the polymer and the acetic acid molecule.
  • acetic acid is believed to facilitate radical formation and stability permitting more efficient crosslinking reactions.
  • the crosslinking foam polyolefin elastomer may alternatively and/or additionally tuned for desired material properties by applying acetic acid, a protic acid, and/or a Lewis acid based catalyst.
  • the acid catalyst may be a Bronsted type acid with a pKa less than 20, less than 15, less than 10, less than 5, less than 4, less than 3, less than 2, less than 1, or even less than zero.
  • the crosslinker can be utilized to initiate the crosslinking process of the polyolefin elastomer and/or the ethylene vinyl acetate (EVA) copolymer by reacting with the respective polyolefins to form a reactive species that can react and/or couple with the respective polyolefin elastomer and/or the ethylene vinyl acetate (EVA) copolymer chains.
  • the crosslinker can include halogen molecules, azo compounds (e.g., azobisisobutyl), carboxylic peroxyacids, peroxyesters, peroxyketals, and peroxides (e.g., alkyl hydroperoxides, dialkyl peroxides, and diacyl peroxides).
  • the crosslinker is an organic peroxide selected from di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butyl- peroxy)hexyne-3, l,3-bis(t-butyl-peroxy- isopropyl)benzene, n-butyl-4,4-bis(t-butyl- peroxy)valerate, benzoyl peroxide, t- butylperoxybenzoate, t-butylperoxy isopropyl carbonate, and t-butylperbenzoate, as well as bis(2-methylbenzoyl)peroxide, bis(4- methylbenzoyl)peroxide, t-butyl peroctoate, cumene hydroperoxide, methyl ethyl ketone peroxide, lauryl peroxide, tert-butyl
  • the grafting initiator is present in an amount of from greater than 0 wt % to about 2 wt % of the composition, including from about 0.15 wt % to about 1.2 wt % of the composition.
  • the amount of initiator and silane employed may affect the final structure of the silane grafted polymer (e.g., the degree of grafting in the grafted polymer and the degree of crosslinking in the cured polymer).
  • the reactive composition contains at least 100 ppm of initiator, or at least 300 ppm of initiator.
  • the initiator may be present in an amount from 300 ppm to 1500 ppm or from 300 ppm to 2000 ppm.
  • the silane:initiator weight ratio may be from about 20:1 to about 400:1, including from about 30:1 to about 400:1, from about 48:1 to about 350:1, and from about 55:1 to about 333:1.
  • the crosslinker present in the dry mix can form a dual crosslinking system.
  • This dual crosslinking system can provide both silane graft-silane graft crosslinks and carbon-carbon crosslinks along the hydrocarbon backbone.
  • the incorporation of both silane graft-silane graft and carbon-carbon backbone crosslinks can afford foamed articles that provide exceptional material properties including compression set, rebound resilience, and hardness levels that are ideal for footwear applications.
  • the condensation catalyst can facilitate both the hydrolysis and subsequent condensation of the silane grafts on the silane-grafted polyolefin elastomer to form crosslinks.
  • the crosslinking can be aided by the use of an electron beam radiation.
  • the condensation catalyst can include, for example, organic bases, carboxylic acids, and organometallic compounds (e.g., organic titanates and complexes or carboxylates of lead, cobalt, iron, nickel, zinc, and tin).
  • the condensation catalyst can include fatty acids and metal complex compounds such as metal carboxylates; aluminum triacetyl acetonate, iron triacetyl acetonate, manganese tetraacetyl acetonate, nickel tetraacetyl acetonate, chromium hexaacetyl acetonate, titanium tetraacetyl acetonate and cobalt tetraacetyl acetonate; metal alkoxides such as aluminum ethoxide, aluminum propoxide, aluminum butoxide, titanium ethoxide, titanium propoxide and titanium butoxide; metal salt compounds such as sodium acetate, tin octylate, lead octylate, cobalt octylate, zinc octylate, calcium octylate, lead naphthenate, cobalt naphthenate, dibutyltin dioctoate, di
  • the condensation catalyst can include ibutyltindilaurate, dioctyltinmaleate, dibutyltindiacetate, dibutyltindioctoate, stannous acetate, stannous octoate, lead naphthenate, zinc caprylate, and cobalt naphthenate.
  • a single condensation catalyst or a mixture of condensation catalysts may be utilized.
  • the condensation catalyst(s) may be present in an amount of from about 0.01 wt % to about 1.0 wt %, including from about 0.25 wt % to about 8 wt %, based on the total weight of the silane-grafted polyolefin elastomer/blend composition.
  • a crosslinking system can include and use one or all of a combination of radiation, heat, moisture, and additional condensation catalyst.
  • the condensation catalyst may be present in an amount of from 0.25 wt % to 8 wt %. In other aspects, the condensation catalyst may be included in an amount of from about 1 wt % to about 10 wt % or from about 2 wt % to about 5 wt %.
  • the foaming agent can be a chemical foaming agent (e.g., organic or inorganic foaming agent) and/or a physical foaming (e.g., gases and volatile low weight molecules) that is added to the silane-grafted polyolefin elastomer and condensation catalyst blend during the extrusion and/or molding process to produce the crosslinked foam polyolefin elastomers.
  • a chemical foaming agent e.g., organic or inorganic foaming agent
  • a physical foaming e.g., gases and volatile low weight molecules
  • the foaming agent may be a physical foaming agent including the microencapsulated foaming agent, otherwise referred to in the art as a microencapsulated blowing agent (MEBA).
  • MEBAs include a family of physical foaming agents that are defined as a thermo expandable microsphere which is formed by the encapsulation of a volatile hydrocarbon into an acrylic copolymer shell. When the acrylic copolymer shell expands, the volatile hydrocarbon (e.g., butane) creates a foam in the silane-crosslinkable polyolefin elastomer and reduces its weight.
  • the MEBAs have an average particle size of from about 20 pm to about 30 pm.
  • Exemplary MEBAs include those sold under the trade name MATSUMOTO F-AC170D.
  • MEBA's may be used in combination with other foaming agents including organic and inorganic foaming agents.
  • the foaming agent may be a combination of endothermic and/or exothermic foaming compounds that can create a cell structure using a water releasing agent to accelerate the curing times, e.g. 40 seconds to 100 seconds, in the mold having a temperature greater than 150 °C.
  • Organic foaming agents that may be used can include, for example, azo compounds, such as azodicarbonamide (ADCA), barium azodicarboxylate, azobisisobutyronitrile (AIBN), azocyclohexylnitrile, and azodiaminobenzene, N-nitroso compounds, such as N,N'- dinitrosopentamethylenetetramine (DPT), N,N'-dimethyl-N,N'-dinitrosoterephthalamide, and trinitrosotrimethyltriamine, hydrazide compounds, such as 4,4'- oxybis(benzenesulfonylhydrazide)(OBSH), paratoluene sulfonylhydrazide, diphenylsulfone- 3,3'-disulfonylhydrazide, 2,4-toluenedisulfonylhydrazide, p,p- bis(benzenesulfonyl
  • azo compounds and N-nitroso compounds are used.
  • azodicarbonamide (ADCA) and N,N'- dinitrosopentamethylenetetramine (DPT) are used.
  • the organic foaming agents listed above may be used alone or in any combination of two or more.
  • the decomposition temperature and amount of organic foaming agent used can have important consequences on the density and material properties of the crosslinked foam polyolefin elastomers.
  • the organic foaming agent has a decomposition temperature of from about 150 °C to about 210 °C.
  • the organic foaming agent can be used in an amount of from about 0.1 wt % to about 40 wt %, from about 5 wt % to about 30 wt %, from about 5 wt % to about 20 wt %, from about 10 wt % to about 30 wt %, or from about 1 wt % to about 10 wt % based on the total weight of the polymer blend.
  • organic foaming agent has a decomposition temperature lower than 150° C, early foaming may occur during compounding. Meanwhile, if the organic foaming agent has a decomposition temperature higher than 210° C, it may take longer, e.g., greater than 15 minutes, to mold the foam, resulting in low productivity. Additional foaming agents may include any compound whose decomposition temperature is within the range defined above.
  • the inorganic foaming agents that may be used include, for example, hydrogen carbonate, such as sodium hydrogen carbonate and ammonium hydrogen carbonate; carbonate, such as sodium carbonate and ammonium carbonate; nitrite, such as sodium nitrite and ammonium nitrite; borohydride, such as sodium borohydride; and other known inorganic foaming agents, such as azides.
  • hydrogen carbonate may be used.
  • sodium hydrogen carbonate may be used.
  • the inorganic foaming agents listed above may be used alone or in any combination of two or more.
  • the inorganic foaming agent can be used in an amount of from about 0.1 wt % to about 40 wt %, from about 5 wt % to about 30 wt %, from about 5 wt % to about 20 wt %, from about 10 wt % to about 30 wt %, or from about 1 wt % to about 10 wt % based on the total weight of the polymer blend.
  • Physical blowing agents that may be used include, for example, supercritical carbon dioxide, supercritical nitrogen, butane, pentane, isopentane, cyclopentane.
  • various minerals or inorganic compounds e.g., talc and calcium carbonate may be used as a nucleating agent for the supercritical fluid.
  • the physical foaming agent can be used in an amount of from about 0.1 wt % to about 40 wt %, from about 5 wt % to about 30 wt %, from about 5 wt % to about 20 wt %, from about 10 wt % to about 30 wt %, or from about 1 wt % to about 10 wt % based the total weight of the polymer blend.
  • the crosslinked foam polyolefin elastomers may optionally include one or more fillers.
  • the filler(s) may be extruded with the silane-grafted polyolefin.
  • the filler(s) may include metal oxides, metal hydroxides, metal carbonates, metal sulfates, metal silicates, clays, talcs, carbon black, and silicas. Depending on the application and/or desired properties, these materials may be fumed or calcined.
  • the metal of the metal oxide, metal hydroxide, metal carbonate, metal sulfate, or metal silicate may be selected from alkali metals (e.g., lithium, sodium, potassium, rubidium, caesium, and francium); alkaline earth metals (e.g., beryllium, magnesium, calcium, strontium, barium, and radium); transition metals (e.g., zinc, molybdenum, cadmium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium, zirconium, niobium, technetium, ruthernium, rhodium, palladium, silver, hafnium, taltalum, tungsten, rhenium, osmium, indium, platinum, gold, mercury, rutherfordium, dubnium, seaborgium, bohrium, hassium,
  • alkali metals e.g.
  • the filler(s) of the crosslinked foam polyolefin elastomers or blend may be present in an amount of from greater than 0 wt % to about 50 wt %, including from about 1 wt % to about 20 wt %, and from about 3 wt % to about 10 wt %.
  • the crosslinked foam polyolefin elastomers and/or the respective articles formed may also include waxes (e.g., paraffin waxes, microcrystalline waxes, HDPE waxes, LDPE waxes, thermally degraded waxes, byproduct polyethylene waxes, optionally oxidized Fischer-Tropsch waxes, and functionalized waxes).
  • waxes e.g., paraffin waxes, microcrystalline waxes, HDPE waxes, LDPE waxes, thermally degraded waxes, byproduct polyethylene waxes, optionally oxidized Fischer-Tropsch waxes, and functionalized waxes.
  • the wax(es) are present in an amount of from about 0 wt % to about 10 wt %.
  • Tackifying resins e.g., aliphatic hydrocarbons, aromatic hydrocarbons, modified hydrocarbons, terpens, modified terpenes, hydrogenated terpenes, rosins, rosin derivatives, hydrogenated rosins, and mixtures thereof
  • the tackifying resins may have a ring and ball softening point in the range of from 70 °C to about 150 °C and a viscosity of less than about 3,000 cP at 177 °C.
  • the tackifying resin(s) are present in an amount of from about 0 wt % to about 10 wt %.
  • the crosslinked foam polyolefin elastomers may include one or more oils.
  • oils include white mineral oils and naphthenic oils.
  • the oil(s) are present in an amount of from about 0 wt % to about 10 wt %.
  • the synthesis/production of the reagent silane-grafted polyolefin elastomers may be performed as described in the grafting steps outlined using the single-step Monosil process or the two-step Sioplas process as disclosed in United States Patent Application No. 15/836,436, filed December 8, 2017, entitled "SHOE SOLES, COMPOSITIONS, AND METHODS OF MAKING THE SAME" which is herein incorporated by reference in its entirety.
  • a method 200 for making a shoe sole includes a step 204 of mixing a silane-grafted polyolefin, an ethylene vinyl acetate (EVA) copolymer, a crosslinker, a foaming agent, and a condensation catalyst together to form a dry mix.
  • the dry mix may exist in a stable or unreactive form until it is heated to activate the crosslinker, foaming agent, and/or condensation catalyst.
  • step 208 of extruding the silane-grafted polyolefin, the ethylene vinyl acetate (EVA) copolymer, the crosslinker, the foaming agent, and the condensation catalyst together to form a crosslinkable polyolefin blend.
  • step 212 of injection molding the crosslinkable polyolefin blend into a shoe sole element.
  • the shoe sole can exhibit a compression set of from about 1.0 % to about 50.0 %, as measured according to ASTM D 395 (48 hrs @ 50 °C) and has a density less than 0.88 g/cm 3 .
  • a dry blend may be formed by adding a polyolefin elastomer to an EVA blend.
  • the dry blend may include from about 10 % to about 90 %, from about 20 % to about 80 %, from about 20 % to about 60 %,from about 40 % to about 80 % or from about 60 % to about 80 % polyolefin elastomer.
  • the dry blend may additionally include and from about 10 % to about 90 %, from about 20 % to about 80 %, from about 20 % to about 60 %, from about 40 % to about 80 % or from about 60 % to about 80 % EVA blend.
  • the EVA blend may include EVA, the crosslinker, the condensation catalyst, and/or the foaming agent.
  • Injecting or adding the silane-crosslinkable polyolefin elastomer blend 298 into the shoe sole mold 302 to form a shoe sole element 314 may be performed using one of several different approaches. Depending on the molding approach selected, different material properties may be achieved for the midsole 18.
  • the molding can be performed by using one of the four following processes: Compression Molding (FIG. 5), Injection Molding (FIG. 6), Injection Compression Molding (FIG. 7), and Supercritical Injection Molding (FIG. 8).
  • FIG. 5 a schematic cross-sectional view of a compression mold 458 is provided.
  • the silane-crosslinkable polyolefin elastomer 298 (or shoe sole element 314, not shown) is pressurized in the compression mold or press 458 under predetermined temperature, pressure, and time conditions to obtain a crosslinked foam polyolefin elastomers in the form of a plate-like sponge (not shown).
  • the compression mold 458 includes an upper mold 460 and a lower mold 464.
  • the silane-crosslinkable polyolefin elastomer 298 is heated and pressed in the compression mold 458, the chemical and/or physical foaming agents are activated to form the crosslinked foam polyolefin elastomers.
  • Portions and/or edges of plate-like sponge may then be skived, cut, and/or ground into a midsole 18 having a desired thickness and shape (see FIGS. 1-2). Subsequently, the midsole 18 is again molded in a final mold with the outsole 14 and other respective components under heat and pressure and the assembly is then pressurized during cooling in a closed state of the mold (this process is called "phylon molding" in the shoe industry) to produce a final shoe sole (e.g., shoe sole 10).
  • FIG. 6 a schematic cross-sectional view of an injection mold is provided.
  • the reactive single screw extruder 288, 444 used in either the Sioplas or Monosil process prepares and injects the silane- crosslinkable polyolefin elastomer 298 into the mold 302 having an upper mold 306 and a lower mold 310.
  • an uncured midsole 18a is formed as provided in step 1 of FIG. 6.
  • the chemical and/or physical foaming agents are activated to form the crosslinked foam polyolefin elastomers.
  • the mold 302 used in these aspects is designed to have a smaller size than the size of the final cured midsole 18 (crosslinked foam polyolefin elastomers). After foaming and expansion of the silane- crosslinkable polyolefin elastomer, the uncured midsole 18a is expanded to the desired size of the midsole 18 and the mold 302 releases as provided in step 2 of FIG. 6.
  • FIG. 7 a schematic cross-sectional view of an injection compression mold is provided.
  • the injection compression mold provides a hybrid approach to forming the midsole 18 by using aspects of both the compression mold described in FIG. 5 and the injection mold described in FIG. 6.
  • the reactive single screw extruder 288, 444 used in either the Sioplas or Monosil process prepares and injects a mass of the silane-crosslinkable polyolefin elastomer 298 into the mold 302 having an upper mold 306 and a lower mold 310 as provided in step 1 of FIG. 7.
  • the mass of silane-crosslinkable polyolefin elastomer 298 is then heated and pressed in the mold 302 to form the uncured midsole 18a while the chemical and/or physical foaming agents are activated to form the crosslinked foam polyolefin elastomers making up the final cured midsole 18 as provided in step 2 of FIG. 7.
  • the mold 302 used in these injection compression processes is designed to have a smaller size than the size of the final cured midsole 18 (crosslinked foam polyolefin elastomers). After foaming and expansion of the silane-crosslinked polyolefin elastomer, the mold 302 is released to eject the final cured midsole 18 as provided in step 3 of FIG. 7.
  • FIG. 8 a schematic cross-sectional view of a reactive single screw extruder 480 equipped with a supercritical fluid injector 484 is provided.
  • the process begins by extruding (e.g., with the reactive single screw extruder 480) the first polyolefin 240 having a density less than 0.86 g/cm 3 , the second polyolefin 244, the silan cocktail 248 including the silane crosslinker (e.g., vinyltrimethoxy silane, VTMO and/or vinyltriethoxy silane, VTEO), grafting initiator (e.g.
  • the silane crosslinker e.g., vinyltrimethoxy silane, VTMO and/or vinyltriethoxy silane, VTEO
  • grafting initiator e.g.
  • the first polyolefin 240, second polyolefin 244, and silan cocktail 248 may be added to the reactive single screw extruder 480 using an addition hopper 440 and gear pump 268.
  • the silan cocktail 248 may be added to a single screw 448 further down the extrusion line to help promote better mixing with the first and second polyolefin 240, 244 blend.
  • one or more optional additives 284 may be added with the first polyolefin 240, second polyolefin 244, and silan cocktail 248 to tweak the final material properties of the silane- crosslinkable polyolefin blend 298.
  • the supercritical fluid injector 484 may be used to add a supercritical fluid such as carbon dioxide or nitrogen to the silane-crosslinkable polyolefin blend 298 before it is injected through the die 300 into the mold 302.
  • the reactive single screw extruder 480 then injects the silane-crosslinkable polyolefin elastomer 298 into the mold 302 having an upper mold 306 and a lower mold 310.
  • an uncured midsole 18a is formed as provided in step 1 of FIG. 8.
  • the supercritical fluid foaming agent expands to form the crosslinked foam polyolefin elastomers.
  • the mold 302 used in these aspects is designed to have a smaller size than the size of the final cured midsole 18 (crosslinked foam polyolefin elastomers). After foaming, the crosslinked foam polyolefin elastomers is expanded to the desired size of the midsole 18 using core pull back to accommodate the expansion, and the mold releases as provided in step 2 of FIG. 8.
  • the use of the crosslinker with the silane-grafted polyolefin to provide the dual crosslinking system provides a crosslinked foam polyolefin article that can have ideal properties for numerous polymer foam applications.
  • the crosslinked foam polyolefin article may have a low specific gravity or density that makes the foam material light weight, soft, and comfortable for use as a shoe sole, sole liner, insole, mid sole, and/or outer sole.
  • the crosslinked network of the crosslinked foam polyolefin article can also increase/improve the foam article's stability, rebound energy, and resilience.
  • the crosslinked network of the crosslinked foam polyolefin article provides a reduced dynamic compression set resulting in improved longevity.
  • the network architecture of the crosslinked foam polyolefin article provides temperature independent stiffness and a high energy return.
  • the network architecture helps ensure a broad temperature resistance.
  • a low glass transition temperature guarantees a broad temperature resistance and short chain branching POE and OBC foams recover faster than highly branched EVA.
  • the random orientation and positioning of the ethylene co-polymers provide flexibility and softness.
  • thermoplastic as used herein, is defined to mean a polymer that softens when exposed to heat and returns to its original condition when cooled to room temperature.
  • thermoset as used herein, is defined to mean a polymer that solidifies and irreversibly “sets” or “crosslinks” when cured. In either of the Monosil or Sioplas processes described above, it is important to understand the careful balance of thermoplastic and thermoset properties of the various different materials used to produce the final thermoset crosslinked foam polyolefin elastomers or midsole 18.
  • Each of the intermediate polymer materials mixed and reacted using a reactive twin screw extruder, a non-reactive single screw extruder, and a reactive single screw extruder are thermosets.
  • the silane- grafted polyolefin blend and the silane-crosslinkable polyolefin blend are thermoplastics and can be softened by heating so the respective materials can flow.
  • the silane-crosslinkable polyolefin blend can begin to crosslink or cure at a temperature greater than 150 °C and an ambient humidity to form the midsole 18 and crosslinked foam polyolefin elastomers blend.
  • the silane-crosslinkable polyolefin blend can be foamed and crosslinked in a molding time from 40 seconds to 400 seconds, from 40 seconds to 200 seconds, from 40 seconds to 100 seconds, or in about 60 seconds.
  • thermoplastic/thermoset behavior of the silane-crosslinkable polyolefin blend and corresponding crosslinked foam polyolefin elastomers blend are important for the various compositions and articles disclosed herein (e.g., midsole 18 shown in FIG. 1) because of the potential energy savings provided using these materials.
  • a manufacturer can save considerable amounts of energy by being able to cure the silane- crosslinkable polyolefin blend at a temperature greater than 150 °C and an ambient humidity. This curing process is typically performed in the industry by applying significant amounts of energy to heat or steam treat crosslinkable polyolefins.
  • the ability to cure the inventive silane-crosslinkable polyolefin blend with a lower relative temperature and/or ambient humidity or by shortening the cure time at elevated temperatures are not properties necessarily intrinsic to crosslinkable polyolefins. Rather, this temperature/humidity curing capability is a property dependent on the relatively low density of the silane-crosslinkable polyolefin blend. In some aspects, no additional curing ovens, heating ovens, steam ovens, or other forms of heat producing machinery other than what was provided in the extruders are used to form the crosslinked foam polyolefin elastomers.
  • the specific gravity of the crosslinked foam polyolefin elastomers of the present disclosure may be lower than the specific gravities of existing TPV and EPDM formulations used in the art.
  • the reduced specific gravity of these materials can lead to lower weight shoes, thereby helping shoe manufacturers meet increasing demands for lighter weight shoes.
  • the specific gravity of the crosslinked foam polyolefin elastomers of the present disclosure may be from about 0.10 g/cm 3 to about 0.50 g/cm 3 , from about 0.15 g/cm 3 to about 0.50 g/cm 3 , from about 0.15 g/cm 3 to about 0.40 g/cm 3 , from about 0.15 g/cm 3 to about 0.35 g/cm 3 , from about 0.20 g/cm 3 to about 0.40 g/cm 3 , from about 0.20 g/cm 3 to about 0.45 g/cm 3 , from about 0.25 g/cm 3 to about 0.35 g/cm 3 , from about 0.30 g/cm 3 to about 0.50 g/cm 3 , from about 0.30 g/cm 3 to about 0.40 g/cm 3 , from about 0.35 g/cm 3 to about 0.50 g/cm 3 , from about 0.35 g/cm 3
  • the specific gravity may be less than about 0.50 g/cm 3 , less than about 0.45 g/cm 3 , less than about 0.40 g/cm 3 , less than about 0.35 g/cm 3 , less than about 0.30 g/cm 3 , less than about 0.25 g/cm 3 , less than about 0.20 g/cm 3 , or less than about 0.15 g/cm 3
  • the crosslinked foam polyolefin elastomers may be produced as a closed celled foam.
  • the pore size of the crosslinked foam polyolefin elastomers may be from about 0.10 mm to about 0.50 mm, from about 0.10 mm to about 0.40 mm, from about 0.10 mm to about 0.30 mm, from about 0.10 mm to about 0.25 mm, from about 0.10 mm to about 0.50 mm, or about 0.10 mm, about 0.12 mm, about 0.14 mm, about 0.16 mm, about 0.18 mm, about 0.20 mm, about 0.22 mm, about 0.24 mm, about 0.26 mm, about 0.28 mm, or about 0.30 mm.
  • crosslinked foam polyolefin elastomers of the present disclosure
  • crosslinked foam polyolefin elastomers A smaller area exists between the stress/strain curves for the crosslinked foam polyolefin elastomers of the disclosure, as compared to the areas between the stress/strain curves for the two EPDM materials. This smaller area between the stress/strain curves for the crosslinked foam polyolefin elastomers can be desirable for midsoles.
  • Elastomeric materials typically have non-linear stress- strain curves with a significant loss of energy when repeatedly stressed.
  • the crosslinked foam polyolefin elastomers of the present disclosure may exhibit greater elasticity and less viscoelasticity (e.g., they have linear curves and exhibit very low energy loss).
  • Embodiments of the crosslinked foam polyolefin elastomers described herein do not have any filler or plasticizer incorporated into these materials so their corresponding stress/strain curves do not have or display any Mullins effect and/or Payne effect.
  • the lack of Mullins effect for these crosslinked foam polyolefin elastomers is due to the lack of any filler or plasticizer added to the crosslinked foam polyolefin elastomers blend so the stress/strain curve does not depend on the maximum loading previously encountered where there is no instantaneous and irreversible softening.
  • the crosslinked foam polyolefin elastomers or midsole 18 can exhibit a compression set of from about 1.0 % to about 50.0 %, from about 5.0 % to about 50.0 %, from about 1.0 % to about 40.0 %, from about 5.0 % to about 40.0 %, from about 5.0 % to about 30.0 %, from about 5.0 % to about 25.0 %, from about 5.0 % to about 20.0 %, from about 5.0 % to about 15.0 %, from about 5.0 % to about 10.0 %, from about 10.0 % to about 25.0 %, from about 10.0 % to about 20.0 %, from about 10.0 % to about 15.0 %, from about 15.0 % to about 30.0 %, from about 15.0 % to about 25.0 %, from about 15.0 % to about 20.0 %, from about 20.0 % to about 30.0 %, or from about 20.0 % to about 25.0 %, from about 1.0
  • the crosslinked foam polyolefin elastomers or midsole 18 can exhibit a compression set of from about 5.0 % to about 20.0 %, from about 5.0 % to about 15.0 %, from about 5.0 % to about 10.0 %, from about 7.0 % to about 20.0 %, from about 7.0 % to about 15.0 %, from about 7.0 % to about 10.0 %, from about 9.0 % to about 20.0 %, from about 9.0 % to about 15.0 %, from about 9.0 % to about 10.0 %, from about 10.0 % to about 20.0 %, from about 10.0 % to about 15.0 %, from about 12.0 % to about 20.0 %, or from about 12.0 % to about 15.0 %, from about 1.0 % to about 50.0 %, as measured according to ASTM D 395 (48 hrs @ 23 °C, 50 °C, 70 °C, 80 °C, 90 °C
  • the crosslinked foam polyolefin elastomers or midsole 18 may exhibit a crystallinity of from about 5 % to about 40 %, from about 5 % to about 25 %, from about 5 % to about 15 %, from about 10 % to about 20 %, from about 10 % to about 15 %, or from about 11 % to
  • the crosslinked foam polyolefin elastomers or midsole 18 may exhibit a glass transition temperature of from about -75 °C to about -25 °C, from about -65 °C to about -40 °C, from about -60 °C to about -50 °C, from about -50 °C to about -25 °C, from about -50 °C to about -30 °C, or from about -45 °C to about -25 °C as measured according to differential scanning calorimetry (DSC) using a second heating run at a rate of 5 °C/min or 10 °C/min.
  • DSC differential scanning calorimetry
  • the crosslinked foam polyolefin elastomers or midsole 18 may exhibit a rebound resilience of at least 10 %, at least 20 %, at least 30 %, at least 40 %, at least 50 %, at least 60 %, at least 70 %, at least 80 %, or at least 90 %.
  • FIGS. 9 and 10 a resilience versus specific gravity plot and a hardness versus specific gravity plot for a variety of crosslinked materials, respectively, are provided according to some aspects of the present disclosure.
  • inventive crosslinked and foamed polyolefin elastomer demonstrated similar elevated resilience (greater than 70 %) as the styrene- ethylene-butylene-styrene (SEBS)(P1083) while the EVA (Elvax 40L03) and olefin block copolymer (OBC)(lnfuse 9107) provide resilience over 60 %.
  • the inventive crosslinked and foamed polyolefin elastomer demonstrated similar elevated hardness (greater than 30 with a positive slope) as the styrene-ethylene-butylene- styrene (SEBS)(P1083) while The EVA (Elvax 40L03) and olefin block copolymer (OBC)(lnfuse 9107) provide resilience over 60 %.
  • SEBS styrene-ethylene-butylene-styrene
  • OBC olefin block copolymer
  • FIG. 19 a graph depicting volume loss over 1000 cycles for a variety of crosslinked foamed polyolefin elastomers according to some aspects of the present disclosure is provided.
  • the first listed inventive crosslinked foam material provides the least amount of volume loss.
  • a shoe sole or foam article that maintains its volume over extended period of time and use would be expected to be a more reliable material than the other listed comparative foams that shrink or have their porous cell structure deteriorated.
  • a foamed midsole was prepared by dry blending or mixing the various components together and using a compression molding system at 170 °C for 480 seconds to form Examples 1, 2, 3, and 4.
  • the components used in Examples 1-4 are listed below in Table 1 and include a polyolefin elastomer (R3) and/or a silane-grafted polyolefin elastomer having vinyltrimethoxy silane incorporated (MSX-041).
  • R3 polyolefin elastomer
  • MSX-041 silane-grafted polyolefin elastomer having vinyltrimethoxy silane incorporated
  • FIG. 18 is a load versus position plot of the inventive Example 2 crosslinked foamed polyolefin elastomer. The small gap formed between the plot lines as a load is applied and removed from the Example 2 foam illustrated that minimal energy is lost as the load is deflected by the foam providing an excellent example of energy being returned to the system.
  • a foamed midsole was prepared by dry blending or mixing the various components together and using an injection molding system at 190 °C for 360 seconds to form Examples 6-11.
  • the components used in Examples 6-11 are listed below in Table 2 and include a silane-grafted polyolefin elastomer having vinyltrimethoxy silane (VTMO) incorporated (MSX-041), a silane-grafted polyolefin elastomer having vinyltriethoxy silane (VTEO) incorporated (MSX-042), an ethylene vinyl acetate copolymer (SD-23), and/or a blowing agent such as azodicarbonamide (ADCA) listed as JTR-TL.
  • the injection molding system was then used to inject the mixed Example 6-11 compositions.
  • FIGS. 16 and 17 are static compression plots providing compressive strength versus compressive strain for a variety of crosslinked foamed polyolefin elastomers provided in Tables 1 and 2.
  • a foamed midsole was prepared by dry blending or mixing the various components together and using an injection molding system at 190 °C for 360 seconds to form Examples 12-17.
  • the components used in Examples 12-17 are listed below in Table 3 and include a silane-grafted polyolefin elastomer having vinyltrimethoxy silane (VTMO) incorporated (MSX-041), a silane-grafted polyolefin elastomer having vinyltriethoxy silane (VTEO) incorporated (MSX-042), an ethylene vinyl acetate copolymer having silicone oil (SD-24), and/or a blowing agent such as azodicarbonamide (ADCA) listed below as JTR-TL.
  • VTMO vinyltrimethoxy silane
  • VTEO vinyltriethoxy silane
  • SD-24 ethylene vinyl acetate copolymer having silicone oil
  • ADCA azodicarbonamide
  • Example 12-17 The injection molding system was then used to inject the mixed Example 12-17.
  • the measured Density, Expansion Ratio A/B direction (ER %), Hardness (C type), Resilience, Compression Set, Split Tear, and T-shrinkage values for the corresponding crosslinked foam polyolefin elastomers in Examples 12-17 are additionally provided in Table S.
  • a foamed midsole was prepared by dry blending or mixing the various components together and using an injection molding system at 190 °C for various times to form Examples 18-19.
  • the components used in Examples 18-19 are listed below in Table 4 and include a silane-grafted polyolefin elastomer having vinyltrimethoxy silane (VTMO) incorporated (MSX-041), an ethylene vinyl acetate copolymer having silicone oil (SD-24), and/or a blowing agent such as azodicarbonamide (ADCA) listed below as JTR-TL.
  • VTMO vinyltrimethoxy silane
  • SD-24 ethylene vinyl acetate copolymer having silicone oil
  • ADCA azodicarbonamide
  • a foamed midsole was prepared using a reactive twin-screw extruder to extrude 60 wt % INFUSE 9530, 30 wt % INFUSE 9817, and 8 wt % PP Ml 25 (Polypropylene having a melt index of 25) together with 2.0 wt % SILAN RHS 14/032 or SILFIN 29 to form the RH 17/021 silane-grafted polyolefin elastomer.
  • a reactive single screw extruder equipped with the supercritical fluid injector was employed to further process the blend, where the supercritical fluid medium was nitrogen (N 2 ) with a gas flow rate of 0.29 kg/h.
  • the injector open time was 10 sec and the pressure was maintained at 140 bar.
  • a gas load of 0.5 wt % was used with an injection speed of 75 mm/s.
  • the weight of the RHS 17/021 material used was 146 g.
  • the resulting sample has a density of 0.449 g/cm 3 , as measured using a density scale. No condensation catalyst was added and the precision opening was 2 mm.
  • the material properties for Example 20 are listed below in Table 5, where the compression set values were measured according to ASTM D 395 and the density values were measured by measuring the weight, length, width and thickness of a sample (approximately 9cm x 10cm, and 0.2-0.5cm in thickness).
  • FIG. 11 provides a micrographs of a cross-section of the midsole formed using the supercritical nitrogen fluid as the foaming agent as disclosed in this example.
  • a foamed midsole was prepared using a reactive twin-screw extruder to extrude
  • a reactive single screw extruder 288 was then used to load and extrude silane-grafted polyolefin elastomer, with 1.0 wt % dioctyltin dilaurate (DOTL) condensation catalyst, and 10 wt % MEBA chemical foaming agent.
  • DNL dioctyltin dilaurate
  • FIG. 12 provides three different micrographs of cross-sections of midsoles formed using the MEBA chemical foaming agent according to this example.
  • a foamed midsole having a relatively high concentration of silane grafts was prepared using a reactive twin-screw extruder to extrude 59.00 wt % INFUSETM 9530, 30.00 wt % INFUSETM 9817, and 8.00 wt % MOSTENTM NB 425 together with 3.0 wt % SILAN RHS 14/032 or SILFIN 29 to form the silane-grafted polyolefin elastomer.
  • FIG. 13 provides a micrographs of a cross-section of the midsole formed using the MEBA chemical foaming agent according to this example.
  • a foamed midsole having a relatively low concentration of silane grafts was prepared using a reactive twin-screw extruder to extrude 59.00 wt % INFUSETM 9530, 30.00 wt % INFUSETM 9817, and 8.00 wt % MOSTENTM NB 425 together with 3.0 wt % SILAN RHS 14/032 or SILFIN 29 to form the silane-grafted polyolefin elastomer.
  • FIG. 14 provides a micrograph of a cross-section of the midsole formed using the MEBA chemical foaming agent according to this example.
  • FIG. 15 is a static compression plot providing compressive strength versus compressive strain for a variety of commercially available shoe soles listed in Table 9.
  • a foamed midsole was prepared by dry blending or mixing the various components together and using an injection molding system at 190 °C for 360 seconds to form Examples 24-28.
  • the components used in Examples 24-28 are listed below in Table 10 and include a silane-grafted polyolefin elastomer having vinyltrimethoxy silane (VTMO) incorporated (MSX-041), a silane-grafted polyolefin elastomer having vinyltriethoxy silane (VTEO) incorporated (MSX-042), an ethylene vinyl acetate copolymer (SD-2)(SD-7)(SD-21), and/or a blowing agent such as azodicarbonamide (ADCA) listed as JTR-TL.
  • VTMO vinyltrimethoxy silane
  • VTEO vinyltriethoxy silane
  • SD-2(SD-7)(SD-21 ethylene vinyl acetate copolymer
  • ADCA azodicarbonamide
  • Example 24-28 compositions having a condensation catalyst RHS 14/023 e.g., dioctyltin dilaurate (DOTL)
  • DNL dioctyltin dilaurate
  • ER % Density, Expansion Ratio A/B direction (ER %), Hardness (C type), Resilience, Compression Set, Split Tear, and T-shrinkage values for the corresponding crosslinked foam polyolefin elastomers in Examples 24-28 are additionally provided in Table 10.
  • a foamed midsole was prepared using a reactive twin-screw extruder to extrude
  • FIG. 20 is a graph illustrating the compression set of the inventive crosslinked foamed polyolefin elastomer (ED108-2A) as plotted with respect to temperatures ranging from 100 °C to 150 °C.
  • the term “coupled” in all of its forms, couple, coupling, coupled, etc. generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature or may be removable or releasable in nature unless otherwise stated.
  • elements shown as integrally formed may be constructed of multiple parts or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied.
  • the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.

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Abstract

La présente invention concerne un article chaussant. L'article chaussant comprend une semelle de chaussure. La semelle de chaussure comprend un élastomère polyoléfinique en mousse réticulée ayant une densité inférieure à 0,88 g/cm3, l'élastomère polyoléfinique à mousse réticulée comprenant : un élastomère de polyoléfine greffé au silane, un copolymère séquencé d'oléfine greffé au silane, un élastomère polyoléfinique (POE), un copolymère séquencé d'oléfine (OBC), ou une combinaison de ceux-ci ; un copolymère éthylène-acétate de vinyle (EVA) ; un agent de réticulation ; un catalyseur de condensation ; et un agent moussant. La semelle de chaussure présente un ensemble de compression d'environ 1,0 % à environ 50,0 %, tel que mesuré selon la norme ASTM D 395 (48 h à 50 °C).
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WO2021262776A1 (fr) * 2020-06-24 2021-12-30 Dow Global Technologies Llc Durcissement et fonctionnalisation d'interpolymères d'oléfine/silane
WO2023056339A1 (fr) * 2021-09-30 2023-04-06 Dow Global Technologies Llc Mousses polymères recyclables
EP4253437A1 (fr) * 2022-03-28 2023-10-04 EMPA Eidgenössische Materialprüfungs- und Forschungsanstalt Mélange de réticulation à base de silane et procédé de réticulation de polymères thermoplastiques

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WO1998021251A1 (fr) * 1996-11-15 1998-05-22 Sentinel Products Corp. Materiaux greffes au silane pour utilises pour des produits solides et des mousses
EP0852596A1 (fr) * 1995-09-29 1998-07-15 The Dow Chemical Company Polyolefines expansees reticulees et leur procede de production
KR20190097117A (ko) * 2016-12-10 2019-08-20 쿠퍼-스탠다드 오토모티브 인코포레이티드 마이크로-치밀 시일, 조성물, 및 그의 제조 방법

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EP0852596A1 (fr) * 1995-09-29 1998-07-15 The Dow Chemical Company Polyolefines expansees reticulees et leur procede de production
WO1998021251A1 (fr) * 1996-11-15 1998-05-22 Sentinel Products Corp. Materiaux greffes au silane pour utilises pour des produits solides et des mousses
KR20190097117A (ko) * 2016-12-10 2019-08-20 쿠퍼-스탠다드 오토모티브 인코포레이티드 마이크로-치밀 시일, 조성물, 및 그의 제조 방법

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021262776A1 (fr) * 2020-06-24 2021-12-30 Dow Global Technologies Llc Durcissement et fonctionnalisation d'interpolymères d'oléfine/silane
WO2023056339A1 (fr) * 2021-09-30 2023-04-06 Dow Global Technologies Llc Mousses polymères recyclables
EP4253437A1 (fr) * 2022-03-28 2023-10-04 EMPA Eidgenössische Materialprüfungs- und Forschungsanstalt Mélange de réticulation à base de silane et procédé de réticulation de polymères thermoplastiques

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