Reversible Crosslinked Foam Articles and Processes

Abstract

The present disclosure relates to a foam article. In one embodiment, the foam article comprises a crosslinked foam composition formed from starting materials comprising (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and (ii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS) methacrylate. Thereby, a foam article composed of a crosslinked composition comprising (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and (ii) a bond having the following structure (2) is obtained [Chemical 1] JPEG2025524635000014.jpg27170

Description

Technical Field

[0001] Polyolefin elastomer foams are widely used in consumer applications such as in the midsole applications of footwear. Crosslinking can increase the polymer backbone viscosity, which is advantageous in the foaming process and gives the resulting foam improved mechanical properties. Conventional crosslinking is typically induced by free radical processes (peroxides) or by irradiation for the formation of C-C bonds. Conventional crosslinked foams are very stable and cannot be further dissociated by heating or mechanical shearing. Thus, the recyclability and / or reusability of conventionally crosslinked foam articles is very limited or non-existent.

[0002] Considering the worldwide attention to the carbon neutrality and recyclability of plastic materials, the art recognizes the need for crosslinked foam articles that can be reprocessed and / or reused.

Summary of the Invention

[0003] The present disclosure relates to a foam article. In one embodiment, the foam article comprises a crosslinked foam composition formed from starting materials comprising (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and (ii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS) methacrylate. Thereby, a foam article composed of a crosslinked composition comprising (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and (ii) a bond having the following structure (2) is obtained

[0004]

Chemical Formula

[0005] The present disclosure provides a process. In one embodiment, the process includes heating a foam article to a reprocessing temperature, where the foam article comprises (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, (ii) a bond having structure (2), and is composed of a crosslinked composition

[0006]

Chemical formula

[0007] The foam article is formed from a starting material comprising (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and (ii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS) methacrylate. The process includes forming, at the reprocessing temperature, the foam article into a reprocessable polymer composition. The process includes molding, at the reprocessing temperature, the reprocessable polymer composition into a reprocessed preform. The process includes cooling the reprocessed preform to below the reprocessing temperature and forming a second article composed of a re-crosslinked polymer composition composed of (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and (ii) a bond having structure (2).

[0008] Definitions All references to the Periodic Table of the Elements in this specification shall refer to the Periodic Table of the Elements published and copyrighted in 2003 by CRC Press, Inc. Also, any reference to a group shall be to the group reflected in the Periodic Table of the Elements for that element using the IUPAC system for numbering groups. Unless otherwise stated, unless implied from the context, or unless not customary in the art, all parts and percentages are by weight. For the purposes of U.S. patent practice, the contents of any patent, patent application, or publication referred to in this specification are hereby incorporated by reference in their entirety (or their equivalent U.S. versions are so incorporated by reference).

[0009] The numerical ranges disclosed in this specification include all values (including the boundary values) from the lower limit value to the upper limit value. In the case of a range containing explicit values (for example, a range of 1 or 2 or 3 to 5 or 6 or 7), any sub-range between the two explicit values is included (for example, the above range of 1 to 7 includes sub-ranges such as 1 to 2, 2 to 6, 5 to 7, 3 to 7, 5 to 6, etc.).

[0010] Unless otherwise stated, unless implied from the context, or unless not customary in the art, all parts and percentages are by weight, and all test methods are the latest as of the filing date of this disclosure.

[0011] A "foaming agent" is a substance that can generate a cellular structure in a composition through a foaming process.

[0012] The term "block copolymer" or "segmented copolymer" refers to a polymer that includes two or more chemically distinct regions or segments (referred to as "blocks") that are linearly joined, i.e., a polymer that includes chemically distinct units joined end-to-end (covalently) to a polymerization functional group, rather than in a pendant or graft fashion. In one embodiment, the blocks differ in the amount or type of comonomer incorporated therein, density, amount of crystallinity, type of crystallinity (e.g., polyethylene vs. polypropylene), crystallite size resulting from a polymer of such composition, type or degree of tacticity (isotactic or syndiotactic), regioregularity or regiomrandomness, amount of branching including long-chain branching or hyperbranching, homogeneity, or any other chemical or physical property. Block copolymers are characterized by a unique distribution of both polymer polydispersity (PDI or Mw / Mn) and block length distribution due to the effect of a shuttling agent in combination with the catalyst used in their preparation.

[0013] As used herein, the term "composition" refers to a mixture of materials that includes the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0014] The terms "comprising", "including", "having", and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not specifically disclosed. To avoid doubt, all compositions claimed through the use of the term "comprising" may, unless otherwise stated to the contrary, contain any additional additives, adjuvants, or compounds, whether polymeric or otherwise. 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 to the operation. The term "consisting of" excludes any components, steps, or procedures not specifically depicted or listed.

[0015] "Ethylene polymer" is a polymer that contains more than 50 mol% of polymerized ethylene monomer (based on the total amount of polymerizable monomers) and optionally may contain at least one comonomer. Ethylene polymers include ethylene homopolymers and ethylene copolymers (meaning units derived from ethylene and one or more comonomers). The terms "ethylene polymer" and "polyethylene" may be used synonymously. Non-limiting examples of ethylene polymers (polyethylenes) include low density polyethylene (LDPE) and linear polyethylene. Non-limiting examples of linear polyethylene include linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), multi-component ethylene copolymers (EPE), ethylene / α-olefin multi-block copolymers (also known as olefin block copolymers (OBC)), substantially linear or linear plastomers / elastomers, and high density polyethylene (HDPE). Generally, polyethylene can be produced using heterogeneous catalyst systems such as Ziegler-Natta catalysts, Group 4 transition metals and metallocenes, non-metallocene metal centers, homogeneous catalyst systems containing ligand structures such as heteroaryls, heterovalent aryloxyethers, phosphine imines, etc., and others, in gas phase, fluidized bed reactor, liquid phase slurry process reactor, or liquid phase solution process reactor. Combinations of heterogeneous and / or homogeneous catalysts can also be used in either a single reactor or a dual reactor configuration.

[0016] "Ethylene plastomer / elastomer" is a unit derived from ethylene and at least one C3-C 10It is a substantially linear or linear ethylene / α-olefin copolymer containing a uniform short-chain branch distribution derived from α-olefin comonomer units. The ethylene plastomer / elastomer has a density of 0.854 g / cc to 0.920 g / cc. Non-limiting examples of the ethylene plastomer / elastomer include AFFINITY™ plastomers and elastomers (available from The Dow Chemical Company), EXACT™ plastomers (available from ExxonMobil Chemical), Tafmer™ (available from Mitsui), Nexlene™ (available from SK Chemicals Co.), and Lucene™ (available from LG Chem Ltd.).

[0017] "High density polyethylene" (or "HDPE") is an ethylene homopolymer, or an ethylene / α-olefin copolymer containing at least one C4 to C 10 α-olefin comonomer or C4 to C8 α-olefin comonomer, and has a density of 0.940 g / cc, or 0.945 g / cc, or 0.950 g / cc, or 0.953 g / cc to 0.955 g / cc, or 0.960 g / cc, or 0.965 g / cc, or 0.970 g / cc, or 0.975 g / cc, or 0.980 g / cc. HDPE may be a unimodal copolymer or a multimodal copolymer. "Unimodal ethylene copolymer" is an ethylene / C4 to C α-olefin copolymer having one distinct peak in gel permeation chromatography (GPC) showing the molecular weight distribution. 10 α-olefin copolymer. "Multimodal ethylene copolymer" refers to an ethylene / C4 to C α-olefin copolymer having at least two distinct peaks in GPC showing the molecular weight distribution. 10It is an α-olefin copolymer. Examples of multimodality include copolymers having two peaks (bimodality) and copolymers having three or more peaks. Non-limiting examples of HDPE include DOW™ high density polyethylene (HDPE) resin (available from The Dow Chemical Company), ELITE™ enhanced polyethylene resin (available from The Dow Chemical Company), CONTINUUM™ bimodal polyethylene resin (available from The Dow Chemical Company), LUPOLEN™ (available from LyondellBasell), and HDPE products from Borealis, Ineos, and ExxonMobil.

[0018] As used herein, the term “linear low density polyethylene” (or “LLDPE”) refers to a linear ethylene / α-olefin copolymer containing units derived from ethylene and units derived from at least one C3-C 10 α-olefin, or C4-C8 α-olefin comonomer, having a non-uniform short chain branch distribution. LLDPE is characterized by having little to no long chain branching, in contrast to conventional LDPE. LLDPE has a density of from 0.910 g / cc to less than 0.940 g / cc. Non-limiting examples of LLDPE include TUFLIN™ linear low density polyethylene resin (available from The Dow Chemical Company), DOWLEX™ polyethylene resin (available from the Dow Chemical Company), and MARLEX™ polyethylene (available from Chevron Phillips).

[0019] The term "low density polyethylene" (or "LDPE") is also referred to as "high pressure ethylene polymer" or "highly branched polyethylene", and is an ethylene homopolymer, typically produced by high pressure free radical polymerization (≧100 MPa (e.g., 100 - 400 MPa), using a free radical initiator in a tubular reactor or an autoclave reactor). LDPE resins typically have a density in the range of less than 0.915 - 0.940 g / cc. LDPE is different from LLDPE.

[0020] A "foam composition" (or "foam") is a polymer-based composition having a cellular structure. In other words, before contacting with a blowing agent in its natural state, the polymer-based composition does not contain a cellular structure, and after contacting with the blowing agent and under reduced pressure, the polymer-based composition is a foam composition having a cellular structure. The cells can be open cells, closed cells, or a combination thereof. In one embodiment, the cells have a uniform or substantially uniform cell size.

[0021] As used herein, an "olefin polymer" or "polyolefin" is a polymer that contains more than 50 mole percent of polymerized olefin monomers (based on the total amount of polymerizable monomers) and optionally may contain at least one comonomer. Non-limiting examples of olefin polymers include ethylene polymers and propylene polymers.

[0022] A "polymer" is a compound prepared by polymerizing monomers, whether of the same or different types, that provides, in polymerized form, a plurality of and / or repeating "units" or "structural units" that make up the polymer. Thus, the general term "polymer" encompasses the term "homopolymer", which is commonly used to refer to a polymer prepared from only one type of monomer, and the term "copolymer", which is commonly used to refer to a polymer prepared from at least two types of monomers. Also included are all forms of copolymers, such as random and block copolymers. The terms "ethylene / α-olefin polymer" and "propylene / α-olefin polymer" refer to the above-described copolymers prepared by polymerizing ethylene or propylene, respectively, and one or more additional polymerizable α-olefin monomers. Polymers are often referred to as being "made from" one or more specified monomers, such as being "based on" a specified monomer or type of monomer and "containing" a specified monomer content. In this context, however, it should be noted that the term "monomer" is understood to refer to the polymerized residue of the specified monomer and not to non-polymerized species. Generally, polymers herein are referred to as being based on "units" that are the polymerized form of the corresponding monomers.

[0023] A "propylene-based polymer" is a polymer that contains more than 50 weight percent of polymerized propylene monomer (based on the total amount of polymerizable monomers) and may optionally contain at least one comonomer. Propylene-based polymers include propylene homopolymers and propylene copolymers (meaning units derived from propylene and one or more comonomers). The terms "propylene-based polymer" and "polypropylene" may be used synonymously.

[0024] Test Methods The Asker C hardness of the foam composition was measured in accordance with ASTM D2240 on plaques 20 cm (length) × 10 cm (width) × 1 - 2 cm (thickness). One sample was tested for each example. Each sample was measured at least three times (with a 5 - second waiting time between each measurement) across the entire surface of the sample (i.e., at different positions along the sample). The average was recorded.

[0025] The compression set (C - Set) was measured in accordance with Method B of ASTM D395 under conditions of 50% compression for 6 hours at 50 °C. Two cylindrical foam samples, generally referred to as "buttons", with a diameter of 29 mm (±0.5 mm) and a thickness of approximately 19.5 mm (±0.5 mm) were tested for each foam sample, and the average was reported.

[0026] The density was measured in accordance with ASTM D792, and the results are reported in g / cc at 25 °C.

[0027] Dynamic mechanical analysis (DMA). A DMA experiment was performed using a TA Instruments RSA - G2 Solid Analyzer to measure the storage modulus (G'), loss modulus (G''), and damping ratio (tanδ) of the network as a function of temperature and recycling under a nitrogen atmosphere. DMA was operated in tension mode at a frequency of 1 Hz with a vibration strain of 0.03%. Data was collected from room temperature to 160 °C at a heating rate of 3 °C / min.

[0028] Drop - ball rebound (skin and foam). A 5 / 8 - inch diameter steel ball was dropped from a height of 500 mm onto the foam skin layer and foam layer (before and after aging) to measure the rebound %. The rebound % is calculated as the rebound height (mm) * 100 / 500.

[0029] (Ethylene - based polymer) The melt index (MI or I2) was measured in accordance with ASTM D 1238 under conditions of 190 °C / 2.16 kg, and the results are reported in grams per 10 minutes (g / 10 min).

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

DETAILED DESCRIPTION OF THE INVENTION

[0031] The present disclosure provides a foam article. In one embodiment, the foam article includes a crosslinked foam composition. The crosslinked foam composition is formed from a starting material composed of a polymer selected from the group consisting of an ethylene polymer, a polar ethylene polymer, and combinations thereof, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS) methacrylate.

[0032] A. Ethylene Polymer The crosslinked foam composition is formed from a crosslinkable polymer composition (synonymously referred to as "starting material"). The crosslinkable polymer composition includes an ethylene polymer and / or a polar ethylene polymer. The ethylene polymer is an ethylene homopolymer, ethylene / C3-C 10It can be an α-olefin copolymer or an ethylene C4-C8 α-olefin copolymer. The ethylene-based polymer has a melt index (MI) of 0.1 g / 10 min to 100 g / 10 min, or 1 g / 10 min to 100 g / 10 min, or 1 g / 10 min to 50 g / 10 min, or 1 g / 10 min to 25 g / 10 min, or 1 g / 10 min to 10 g / 10 min, or 1 g / 10 min to 5 g / 10 min. Non-limiting examples of suitable ethylene-based polymers include ethylene plastomers / elastomers, high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), ethylene / α-olefin multiblock copolymers, and combinations thereof.

[0033] In one embodiment, the ethylene-based polymer is an ethylene plastomer / elastomer.

[0034] In one embodiment, the ethylene-based polymer is HDPE.

[0035] In one embodiment, the ethylene-based polymer is LLDPE.

[0036] In one embodiment, the ethylene-based polymer is LDPE.

[0037] In one embodiment, the ethylene-based polymer is an ethylene / α-olefin multi-block copolymer. The term "ethylene / α-olefin multi-block copolymer" refers to an ethylene / C4-C8α-olefin multi-block copolymer composed of polymerized ethylene and one copolymerizable C4-C8α-olefin comonomer (and optionally additives), and the polymer is characterized by a plurality of blocks or segments of two polymerized monomer units with different chemical or physical properties, and the blocks are joined (or covalently bonded) in a linear manner. That is to say, the polymer contains chemically distinct units in which the ends are joined to the polymerized ethylenic functional groups. Ethylene / α-olefin multi-block copolymers include block copolymers having two blocks (diblocks) and more than two blocks (multi-blocks). The C4-C8α-olefin is selected from butene, hexene, and octene. The ethylene / α-olefin multi-block copolymer does not contain styrene (i.e., styrene-free), and / or vinyl aromatic monomers, and / or conjugated dienes, or alternatively excludes them. When referring to the amount of "ethylene" or "comonomer" in the copolymer, this is understood to refer to its polymerized unit. In some embodiments, the ethylene / α-olefin multi-block copolymer has the following formula: (AB) nIt can be represented by the formula, where n is at least 1, preferably an integer greater than 1, for example, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or more, "A" represents a hard block or segment, and "B" represents a soft block or segment. A and B are linked or covalently bonded in a substantially linear manner or in a linear pattern, as opposed to a substantially branched or substantially star-shaped manner. In other embodiments, the A blocks and B blocks are randomly distributed along the polymer chain. In other words, the block copolymer typically does not have the following structure: AAA-AA-BBB-BB. In one embodiment, the ethylene / α-olefin multiblock copolymer does not have a third type of block containing different comonomers. In another embodiment, each of block A and block B has monomers or comonomers randomly distributed substantially within the block. In other words, neither block A nor block B contains two or more subsegments (or subblocks) of distinct compositions, such as a tip segment having a composition substantially different from the remaining blocks.

[0038] In one embodiment, ethylene constitutes more than half of the molar fraction of the total ethylene / α-olefin multiblock copolymer, i.e., ethylene constitutes at least 50% by weight of the total ethylene / α-olefin multiblock copolymer. More preferably, ethylene comprises at least 60% by weight, at least 70% by weight, or at least 80% by weight, along with substantially the remainder of the total ethylene / α-olefin multiblock copolymer containing C4-C8 α-olefin comonomers. In one embodiment, the ethylene / α-olefin multiblock copolymer contains 50% to 90% by weight of ethylene, or 60% to 85% by weight of ethylene, or 65% to 80% by weight of ethylene. In the case of many ethylene / octene multiblock copolymers, the composition comprises an ethylene content of more than 80% by weight of the total ethylene / octene multiblock copolymer and an octene content of 10% to 15% or 15% to 20% by weight of the total multiblock copolymer.

[0039] Ethylene / α-olefin multiblock copolymers contain various amounts of "hard" segments and "soft" segments. The "hard" segments are blocks of polymerized units in which ethylene is present in an amount of more than 90 wt%, or 95 wt%, or more than 95 wt%, or more than 98 wt%, up to a maximum of 100 wt% based on the weight of the polymer. In other words, the comonomer content (content of monomers other than ethylene) in the hard segments is less than 10 wt%, or 5 wt%, or less than 5 wt%, or less than 2 wt% based on the weight of the polymer, and can be as low as zero. In some embodiments, the hard segments contain all or substantially all of the units derived from ethylene. The "soft" segments are blocks of polymerized units in which the comonomer content (content of monomers other than ethylene) is more than 5 wt%, or more than 8 wt%, more than 10 wt%, or more than 15 wt% based on the weight of the polymer. In one embodiment, the comonomer content in the soft segments is more than 20 wt%, more than 25 wt%, more than 30 wt%, more than 35 wt%, more than 40 wt%, more than 45 wt%, more than 50 wt%, or more than 60 wt%, and can be up to a maximum of 100 wt%.

[0040] The soft segment may be present in the ethylene / α-olefin multiblock copolymer in an amount of 1 wt% to 99 wt% of the total weight of the ethylene / α-olefin multiblock copolymer, or 5 wt% to 95 wt%, 10 wt% to 90 wt%, 15 wt% to 85 wt%, 20 wt% to 80 wt%, 25 wt% to 75 wt%, 30 wt% to 70 wt%, 35 wt% to 65 wt%, 40 wt% to 60 wt%, or 45 wt% to 55 wt% of the total weight of the ethylene / α-olefin multiblock copolymer. Conversely, the hard segment may be present in a similar range. The weight percentages of the soft segment and the hard segment can be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed, for example, in U.S. Patent No. 7,608,668, entitled "Ethylene / α-Olefin Block Inter-Polymers," filed on March 15, 2006, in the names of Colin L.P. Shan, Lonnie Hazlitt, et al., and assigned to Dow Global Technologies Inc., the disclosure of which is hereby incorporated by reference in its entirety. In particular, the weight percentages and comonomer content of the hard segment and the soft segment may be determined as described in columns 57 to 63 of U.S. Patent No. 7,608,668.

[0041] An ethylene / α-olefin multiblock copolymer comprises two or more chemically distinct regions or segments (referred to as "blocks") joined (or covalently bonded) in a linear fashion, i.e., it contains chemically distinct units that are joined end-to-end rather than pendant or grafted to the polymerized ethylenic functionality. In one embodiment, the blocks differ in the amount or type of comonomer incorporated, density, amount of crystallinity, the size of the microcrystals that may result from a polymer of such composition, the type or degree of stereoregularity (isotactic or syndiotactic), regioregularity or regiomrandomness, the amount of branching (including long-chain branching or hyperbranching), homogeneity, or any other chemical or physical property. Compared to prior art block interpolymers, including interpolymers produced by continuous monomer addition, metallocene catalysts, or anionic polymerization techniques, the ethylene / α-olefin multiblock copolymers of the present invention are, in one embodiment, characterized by both a unique distribution of the polymer polydispersity (PDI or Mw / Mn or MWD), the polydisperse block length distribution, and / or the polydisperse block number distribution due to the effect of a shuttle agent in combination with the multiple catalysts used in their preparation.

[0042] In one embodiment, the ethylene / α-olefin multiblock copolymer is produced in a continuous process and has a polydispersity index (Mw / Mn) of from 1.7 to 3.5, or from 1.8 to 3, or from 1.8 to 2.5, or from 1.8 to 2.2. When produced in a batch or semi-batch process, the ethylene / α-olefin multiblock copolymer has an Mw / Mn of from 1.0 to 3.5, or from 1.3 to 3, or from 1.4 to 2.5, or from 1.4 to 2.

[0043] Furthermore, the ethylene / α-olefin multi-block copolymer has a PDI (or Mw / Mn) that conforms to the Schultz-Flory distribution rather than the Poisson distribution. This ethylene / α-olefin multi-block copolymer has both a polydisperse block distribution and a polydisperse distribution of block sizes. Thereby, a polymer product having improved distinguishable physical properties is formed. The theoretical advantages of the polydisperse block distribution have already been modeled and considered in Potemkin, Physical Review E (1998) 57(6), pp. 6902-6912, and Dobrynin, J. Chem. Phys. (1997) 107(21), pp9234-9238.

[0044] In one embodiment, this ethylene / α-olefin multi-block copolymer has a most probable distribution of block lengths.

[0045] In a further embodiment, the ethylene / α-olefin multi-block copolymer of the present disclosure, particularly that made in a continuous solution polymerization reactor, has a most probable distribution of block lengths. In one embodiment of the present disclosure, the ethylene / α-olefin multi-block copolymer is defined as having: (A) an Mw / Mn of from about 1.7 to about 3.5, at least one melting point Tm (in degrees Celsius), and a density d (in grams per cubic centimeter), where the numerical values of Tm and d are related by: Tm > -2002.9 + 4538.5(d) - 2422.2(d) 2 corresponding; and / or (B) characterized by an Mw / Mn of from about 1.7 to about 3.5, and a heat of fusion DH in units of J / g, and a delta amount DT in degrees Celsius defined as the temperature difference between the highest DSC peak and the highest crystallization analysis fraction (“CRYSTAF”) peak, where the numerical values of DT and DH have the following relationship: when DH is greater than zero and at most 130 J / g, DT > -0.1299DH + 62.81, when DH is greater than 130 J / g, DT ≧ 48 °C The CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and when less than 5 percent of the polymer has a resolvable CRYSTAF peak, the CRYSTAF temperature is 30 °C; and / or (C) having 300 percent strain and elastic recovery Re (percent) in one cycle measured in a compression molded film of an ethylene / α-olefin interpolymer, having a density d (grams per cubic centimeter), and when the ethylene / α-olefin interpolymer is substantially free of a crosslinked phase, the numerical values of Re and d are related by: Re > 1481 - 1629(d) to satisfy; and / or (D) having a molecular fraction eluting at 40 °C to 130 °C when fractionated using TREF, the fraction having a comonomer molar content at least 5 percent higher than an equivalent random ethylene interpolymer fraction eluting between the same temperatures, the equivalent random ethylene interpolymer having the same comonomer and having a melt index, density, and comonomer molar content (based on the total polymer) within 10 percent of the ethylene / α-olefin interpolymer; and / or (E) having a storage modulus G'(25 °C) at 25 °C and a storage modulus G'(100 °C) at 100 °C, the ratio of G'(25 °C) to G'(100 °C) being in the range of about 1:1 to about 9:1.

[0046] The ethylene / α-olefin multi-block copolymer may also have: (F) a molecular fraction eluting at 40 °C to 130 °C when fractionated using TREF, the fraction having a block index of at least 0.5 and at most 1 and a molecular weight distribution Mw / Mn greater than 1.3; and / or (G) an average block index greater than zero and at most 1.0 and a molecular weight distribution Mw / Mn greater than 1.3.

[0047] It is understood that the ethylene / α-olefin multi-block copolymer may have one, several, all, or any combination of the properties (A) to (G). The block index can be determined as detailed in U.S. Patent No. 7,608,668, which is incorporated herein by reference for that purpose. The analysis methods for determining the properties (A) to (G) are disclosed, for example, in columns 31, line 26 to column 35, line 44 of U.S. Patent No. 7,608,668, which is incorporated herein by reference for that purpose.

[0048] In one embodiment, the ethylene / α-olefin multi-block copolymer has a hard segment and a soft segment, is styrene-free, and consists of only (i) ethylene and (ii) a C4-C8 α-olefin or a C8 α-olefin (and optional additives), and is defined as having an Mw / Mn of 1.7 to 3.5, at least one melting point Tm (in degrees Celsius), and a density d (in grams per cubic centimeter), and the numerical values of Tm and d correspond to the following relationship: Tm > -2002.9 + 4538.5(d) - 2422.2(d) 2 , wherein the density d is 0.850 g / cc, or 0.860 g / cc, or 0.870 g / cc to 0.875 g / cc, or 0.877 g / cc, or 0.880 g / cc, or 0.890 g / cc, and the melting point Tm is 110 °C, or 115 °C, or 120 °C to 125 °C, or 130 °C, or 135 °C.

[0049] In one embodiment, the ethylene / α-olefin multi-block copolymer is an ethylene / 1-octene multi-block copolymer (consisting of only ethylene and octene comonomer) and has one, several, or all of the following properties: (i) an Mw / Mn of 1.7 or 1.8 to 2.2, or 2.5, or 3.5, and / or (ii) a density of 0.860 g / cc or 0.865 g / cc to 0.870 g / cc, or 0.877 g / cc, or 0.880 g / cc, and / or (iii) A melting point Tm of 115 °C, or 118 °C, or 119 °C, or 120 °C to 120 °C, or 123 °C, or 125 °C, and / or (iv) A melt index (MI) of 0.1 g / 10 min or 0.5 g / 10 min to 1.0 g / 10 min, or 2.0 g / 10 min, or 5 g / 10 min, or 10 g / 10 min, and / or (v) 50 to 85 wt% soft segments and 40 to 15 wt% hard segments (based on the total weight of the ethylene / octene multiblock copolymer), and / or (vi) 10 mol%, or 13 mol%, or 14 mol%, or 15 mol% to 16 mol%, or 17 mol%, or 18 mol%, or 19 mol%, or 20 mol% octene in the soft segment, and / or (vii) 0.5 mol%, or 1.0 mol%, or 2.0 mol%, or 3.0 mol% to 4.0 mol%, or 5 mol%, or 6 mol%, or 7 mol%, or 9 mol% octene in the hard segment, and / or (viii) An elastic recovery (Re) of 50% or 60% to 70%, or 80%, or 90% at a strain rate of 300% / min at 21 °C as measured according to ASTM D 1708, and / or ·1 and / or (ix) The polydispersity distribution of the blocks and the polydispersity distribution of the block sizes (hereinafter referred to as the characteristics (i) to (ix) of the multiblock copolymer).

[0050] In one embodiment, the ethylene / α-olefin multiblock copolymer is an ethylene / octene multiblock copolymer. The ethylene / octene multiblock copolymer is sold under the trade name INFUSE™ available from The Dow Chemical Company (Midland, Michigan, USA).

[0051] Ethylene / α-olefin multiblock copolymers can be produced via a chain shuttling process such as that described in U.S. Patent No. 7,858,706, which is incorporated herein by reference. In particular, suitable chain shuttling agents and related information are listed at column 16, line 39 to column 19, line 44. Suitable catalysts are described at column 19, line 45 to column 46, line 19, and suitable cocatalysts are described at column 46, line 20 to column 51, line 28. The process is described throughout the document, and in particular, at column 51, line 29 to column 54, line 56. The process is also described, for example, in: U.S. Patent Nos. 7,608,668, 7,893,166, and 7,947,793.

[0052] The ethylene / α-olefin multiblock copolymer may include more than one ethylene / α-olefin multiblock copolymer.

[0053] B. Polar Ethylene-Based Polymers The foam article (and / or crosslinkable polymer composition) contains an ethylene-based polymer and / or a polar ethylene-based polymer. As used herein, "polar ethylene-based polymer" is an ethylene-based polymer composed of (i) ethylene monomer, (ii) a comonomer containing a heteroatom, and (iii) an optional termonomer (which may or may not contain a heteroatom). In other words, a polar ethylene-based polymer is not a hydrocarbon. The polar ethylene-based polymer has a melt index (MI) of 0.1 g / 10 min to 100 g / 10 min, or 1 g / 10 min to 100 g / 10 min, or 1 g / 10 min to 50 g / 10 min, or 1 g / 10 min to 25 g / 10 min, or 1 g / 10 min to 10 g / 10 min, or 1 g / 10 min to 5 g / 10 min. Non-limiting examples of comonomers having a heteroatom include carbon monoxide, carboxylic acid, ester, alkyl acrylate having 1 to 30 carbon atoms, methacrylate ester having 1 to 30 carbon atoms, vinyl siloxane having 1 to 16 carbon atoms, and halogen. Non-limiting examples of suitable polar ethylene-based polymers include ethylene / carboxylic acid copolymer and metal salt partially neutralized ionomers derived therefrom, ethylene / acrylic acid copolymer (EAA), ethylene / methacrylic acid copolymer (EMAA), ethylene / vinyl(trimethoxy)silane copolymer (EVTMS), ethylene / vinyl acetate copolymer (EVA), ethylene / methyl acrylate (EMA), ethylene / ethyl acrylate copolymer (EEA), ethylene / butyl acrylate copolymer (EBA), ethylene / carbon monoxide (ECO), ethylene / glycidyl methacrylate (E / GMA), ethylene / methyl methacrylate copolymer, ethylene / butyl methacrylate copolymer, ethylene / stearyl acrylate copolymer, ethylene / stearyl methacrylate copolymer, ethylene / octyl acrylate copolymer, ethylene / 2-ethylhexyl acrylate copolymer, ethylene / dodecyl acrylate copolymer, polyvinylidene chloride (PVCD), ethylene / maleic anhydride copolymer (EMAH), polyvinyl chloride (PVC), and combinations thereof.Additional non-limiting examples of terpolymers include ethylene / carboxylic acid / acrylate terpolymers and metal salt partially neutralized ionomers derived therefrom, ethylene / methyl acrylate / vinyl(trimethoxy)silane terpolymer copolymers (EMAVTMS), ethylene / ethyl acrylate / vinyl(trimethoxy)silane terpolymer copolymers (EEAVTMS), ethylene / butyl acrylate / vinyl(trimethoxy)silane terpolymer copolymers (EBAVTMS), ethylene / methyl acrylate / glycidyl methacrylate (EMAGMA), ethylene / butyl acrylate / glycidyl methacrylate (EBAGMA), ethylene / vinyl acetate / maleic anhydride terpolymers (EEAMAH), ethylene ethyl acrylate / maleic anhydride (EEAMAH) terpolymers, and combinations thereof.

[0054] In one embodiment, the polar ethylene-based polymer is an ethylene / vinyl acetate copolymer.

[0055] D. Free Radical Initiator The foam article is formed from a crosslinkable composition comprising an ethylene-based polymer and / or a polar ethylene-based polymer, a free radical initiator, BiTEMPS methacrylate, and optional additives. The crosslinkable composition includes a free radical initiator.

[0056] The amount of free radical initiator in the crosslinkable polymer composition or foam article can be from greater than about 0 to about 10 wt%, from about 0.1 to about 7.5 wt%, or from about 1 to about 5 wt% based on the weight of the ethylene-based polymer and / or polar ethylene-based polymer or polymer blend.

[0057] Non-limiting examples of suitable free radical initiators include peroxides, phenols, azides, aldehyde-amine reaction products, substituted ureas, substituted guanidines; substituted xanthates; substituted dithiocarbamates; sulfur-containing compounds such as thiazoles, sulfenamides, thiuram disulfides, paraquinone dioximes, dibenzoparaquinone dioximes, sulfur, imidazoles; silanes, and combinations thereof.

[0058] In one embodiment, the free radical initiator is an organic peroxide. In certain embodiments, the organic peroxide is a molecule containing carbon atoms, hydrogen atoms, and two or more oxygen atoms, having at least one -O-O- group, provided that when multiple -O-O- groups are present, each -O-O- group is indirectly bonded to another -O-O- group via one or more carbon atoms or a collection of such molecules.

[0059] The organic peroxide may be a dialkyl peroxide. The organic peroxide may be a monoperooxide of the formula RO-O-O-RO, wherein each RO is independently a (C1 - C 20 ) alkyl group or a (C6 - C 20 ) aryl group. Each (C1 - C 20 ) alkyl group is independently unsubstituted or substituted with one or two (C6 - C 12 ) aryl groups. Each (C6 - C 20 ) aryl group is unsubstituted or substituted with 1 - 4 (C1 - C 10 ) alkyl groups. Alternatively, the organic peroxide may be a diperoxide of the formula RO-O-O-R-O-O-RO, wherein R is a divalent hydrocarbon group such as (C2 - C 10 ) alkylene, (C3 - C 10 ) cycloalkylene, or phenylene, and each RO is as defined above.

[0060] The peroxide may be a peroxicarbonate. Suitable peroxicarbonate-type peroxides include isopropyl percarbonate; t-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxy-2-ethylhexyl carbonate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate. The peroxide may be a diacyl peroxide. Non-limiting examples of suitable acyl peroxide-type peroxides include dilauroyl peroxide; benzoyl peroxide; didecanoyl peroxide.

[0061] The peroxide may be a peroxyester. Non-limiting examples of suitable peroxyester-type peroxides include tert-butyl peroxybenzoate, tert-butyl peroxyacetate, tert-amyl peroxybenzoate, tert-butyl peroxy-3,5,5-trimethylhexanoate; tert-butyl peroxyisobutyrate; tert-butyl peroxy diethylacetate; tert-butyl peroxy-2-ethylhexanoate; tert-amyl peroxy-2-ethylhexanoate; 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate; 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane. The peroxide may be a peroxyketal. Non-limiting examples of suitable peroxyketal-type peroxides include 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane; 1,1-di(tert-butylperoxy)cyclohexane; 1,1-di(tert-amylperoxy)cyclohexane.

[0062] The peroxide may be a cyclic ketone peroxide. Non-limiting examples of suitable cyclic ketone peroxides include 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonan.

[0063] Non-limiting examples of suitable organic “peroxides” include bis(1,1-dimethylethyl) peroxide, bis(1,1-dimethylpropyl) peroxide, 2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy)hexane, 2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy)hexyne, 4,4-bis(1,1-dimethylethylperoxy)valeric acid, butyl ester, 1,1-bis(1,1-dimethylethylperoxy)-3,3,5-trimethylcyclohexane, benzoyl peroxide, tert-butyl peroxybenzoate, di-tert-amyl peroxide (DTAP), bis(α-t-butyl-peroxyisopropyl)benzene (BIPB), isopropylcumyl t-butyl peroxide, t-butyl cumyl peroxide, di-t-butyl peroxide, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, 2,5-bis(t-butylperoxy)-2,5-dimethylhex-3-yne, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, isopropylcumyl cumyl peroxide, butyl 4,4-di(tert-butylperoxy)valerate, di(isopropylcumyl) peroxide, dicumyl peroxide, and combinations thereof. Non-limiting examples of suitable commercially available organic peroxides include TRIGONOX™ from AkzoNobel and LUPEROX™ from ARKEMA.

[0064] In one embodiment, the free radical initiator is dicumyl peroxide and / or bis(α-t-butyl-peroxyisopropyl)benzene. In some embodiments, the foam or crosslinkable composition disclosed herein may include a crosslinking aid. As used herein, a "crosslinking aid" is a compound that promotes crosslinking, for example, by helping to establish a higher concentration of reactive sites and / or by helping to reduce the opportunity for detrimental radical side reactions. Examples of crosslinking aids include triallyl cyanurate (TAC), triallyl phosphate (TAP), triallyl isocyanurate (TAIC), 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (vinyl D4), 2,4,6-trimethyl-2,4,6-trivinyl-1,3,5,2,4,6-trioxatrisilinane (vinyl D3), 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinyl-1,3,5,7,9,2,4,6,8,10-pentaoxapentasilecane (vinyl D5), dipentaerythritol penta-acrylate, and trimethylolpropane triacrylate, triallyl trimellitate; N,N,N’,N’,N’’,N’’-hexaallyl-1,3,5-triazine-2,4,6-triamine; triallyl orthoformate, pentaerythritol triallyl ether, triallyl citra-rate, triallyl aconitate; trimethylolpropane triacrylate; trimethylolpropane trimethylacrylate; ethoxylated bisphenol A dimethacrylate; 1,6-hexanediol diacrylate; pentaerythritol tetraacrylate; dipentaerythritol pentaacrylate; tris(2-hydroxyethyl)isocyanurate triacrylate; propoxylated glyceryl triacrylate; polybutadiene having a vinyl content of at least 50 wt%; trivinyl cyclohexane; and mixtures of any two or more thereof, but are not limited thereto.

[0065] Alternatively, crosslinking of the foam or crosslinkable polymer composition disclosed herein can be achieved by using radiation. Non-limiting examples of suitable radiation include electron beam or beta rays, gamma rays, X-rays, or neutron rays. The radiation is thought to activate crosslinking by generating radicals in the polymer that can then combine and crosslink. In some embodiments, the foam or crosslinkable composition is not crosslinked by radiation.

[0066] The radiation dose generally depends on many factors. Suitable radiation levels based on the thickness and shape of the article being irradiated, and the properties of the ethylene-based polymer and / or polar ethylene-based polymer or polymer blend, such as molecular weight, molecular weight distribution, comonomer content, crosslinking accelerator aids, the presence of additives (e.g., oils), etc. Generally, the dose does not exceed the amount necessary to achieve the desired level of crosslinking. In some embodiments, the dose results in more than 5% gel in the foam according to ASTM D-2765-84 Method A.

[0067] In some embodiments, a dual-curing system comprising at least two activation methods selected from free radical initiators and radiation can be effectively used. For example, it may be desirable to use a peroxide free radical initiator in combination with a silane free radical initiator, a peroxide free radical initiator in combination with radiation, a sulfur-containing free radical initiator in combination with a silane free radical initiator, etc.

[0068] It is contemplated that the ethylene-based polymer and / or polar ethylene-based polymer can be blended with other polymers and polyolefins prior to crosslinking.

[0069] E.BiTEMPS methacrylate The foamed article and / or the crosslinkable polymer composition contains 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide, which is synonymously referred to as "BiTEMPS methacrylate" or "BiTEMPS" or "BiT". BiTEMPS methacrylate disulfide has the following Structure 1.

[0070]

Chemical formula

[0071] In one embodiment, the crosslinkable composition is 70 wt% to 98.5 wt%, or 77 wt% to 98.5 wt% of an ethylene-based polymer and / or a polar ethylene-based polymer, 0.5 wt% to 10 wt%, or 0.5 wt% to 5 wt%, 0.5 wt% to 3.0 wt%, or 0.5 wt% to 1.5 wt%, or 1.5 wt% to 3.0 wt% of a free radical initiator which is an organic peroxide (such as dicumyl peroxide, etc.), and 1 wt% to 20 wt%, or 1 wt% to 15 wt%, or 3 wt% to 20 wt%, or 3 wt% to 10 wt% of BiTEMPS methacrylate disulfide. It is understood that the aggregate of the ethylene-based polymer (and / or polar ethylene-based polymer), the free radical initiator, and BiTEMPS methacrylate disulfide (and optional additives) amounts to 100 wt% of the crosslinkable polymer composition.

[0072] The present disclosure provides a crosslinked composition. The crosslinkable polymer composition is melt blended at a temperature of 70°C to 250°C, or 80°C to 200°C, or 90°C to 180°C, or 100°C to 160°C, or 130°C to 250°C, or 140°C to 200°C, or 150°C to 180°C, or 160°C to 175°C to induce a crosslinking reaction and form a crosslinked composition. In one embodiment, the crosslinked composition comprises an ethylene-based polymer and / or a polar ethylene-based polymer, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate). The crosslinked composition contains disulfide bonds formed from BiTEMPS methacrylate by a crosslinking reaction, and the disulfide bonds have the following Structure 2.

[0073] [Chemical formula]

[0074] The term "P" (and structure) in Structure 2 above refers to the chain of polymerized ethylene (and optional comonomer) of the ethylene-based polymer. The ethylene-based polymer (and / or polar ethylene-based polymer) of the crosslinked composition can be any ethylene-based polymer (and / or polar ethylene-based polymer) having an MI of 0.1 g / 10 min to 100 g / 10 min, as disclosed previously herein. Non-limiting examples of suitable ethylene-based polymers (and / or polar ethylene-based polymers) include ethylene plastomers / elastomers, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ethylene / α-olefin multiblock copolymers, ethylene vinyl acetate, and combinations thereof.

[0075] In one embodiment, the ethylene-based polymer and / or the polar ethylene-based polymer (synonymously referred to as “(polar) ethylene-based polymer”) is an unused (polar) ethylene-based polymer. As used herein, an “unused (polar) ethylene-based polymer” is a (polar) ethylene-based polymer that has not been subjected to a crosslinking reaction. In other words, the term “unused (polar) ethylene-based polymer” refers to the (polar) ethylene-based polymer present in the crosslinked composition before the (polar) ethylene-based polymer is crosslinked with BiTEMPS methacrylate. The unused (polar) ethylene-based polymer is the (polar) ethylene-based polymer before crosslinking, and the crosslinked composition contains the same (polar) ethylene-based polymer that was unused but is now crosslinked with BiTEMPS methacrylate. In this way, the unused (polar) ethylene-based polymer serves as a baseline for evaluating the properties of the crosslinked composition. The crosslinked composition (i) has a storage modulus value G’ at 140 °C that is greater than the storage modulus value G’ of the unused ethylene-based polymer at 140 °C, and (ii) has a tan delta value at 60 °C that is less than the tan delta value of the unused ethylene-based polymer at 60 °C, and (iii) has a tan delta value at 140 °C that is less than the tan delta value of the unused ethylene-based polymer at 140 °C.

[0076] In one embodiment, the crosslinked composition comprises 80 wt% to 97 wt% of an ethylene-based polymer and 3 wt% to 20 wt% of BiTEMPS methacrylate, and the aggregate of the ethylene-based polymer and BiTEMPS methacrylate (and optional additives) makes up 100 wt% of the crosslinked composition.

[0077] F. Blend Components In one embodiment, the crosslinkable composition and / or the crosslinked composition includes blend components. Non-limiting examples of suitable blend components include polyolefins (e.g., polyethylene other than ethylene polymers crosslinked with BiTEMPS methacrylate, and polypropylene), polymers (e.g., polystyrene, ABS, SBS, etc.), and combinations thereof. Non-limiting examples of suitable polyolefins include polyethylene, polypropylene, polybutylene (e.g., polybutene-1), polypentene-1, polyhexene-1, polyoctene-1, polydecene-1, poly-3-methylbutene-1, poly-4-methylpentene-1, polyisoprene, polybutadiene, poly-1,5-hexadiene, interpolymers derived from olefins, interpolymers derived from olefins and other polymers, such as polyvinyl chloride, polystyrene, polyurethane, etc., and mixtures thereof.

[0078] In one embodiment, the polyolefin is a homopolymer such as polyethylene, polypropylene, polybutylene, polypentene-1, poly-3-methylbutene-1, poly-4-methylpentene-1, polyisoprene, polybutadiene, poly-1,5-hexadiene, polyhexene-1, polyoctene-1, and polydecene-1.

[0079] Non-limiting examples of suitable polyethylene (other than ethylene polymers crosslinked with BITEMPS methacrylate) as blend components include ultra-low density polyethylene (ULDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), high molecular weight high density polyethylene (HMW-HDPE), ultra high molecular weight polyethylene (UHMW-PE), and combinations thereof. Non-limiting examples of polypropylene include low density polypropylene (LDPP), high density polypropylene (HDPP), high-melt strength polypropylene (HMS-PP), and combinations thereof. In one embodiment, the blend component is high-melt strength polypropylene (HMS-PP), low density polyethylene (LDPE), or a combination thereof.

[0080] G. Additives The crosslinkable composition and / or the crosslinked composition may contain one or more optional additives. Non-limiting examples of suitable additives include graft initiators, crosslinking catalysts, blowing agents, blowing agent activators (e.g., zinc oxide, zinc stearate, etc.), co-agents (e.g., triallyl cyanurate), plasticizers, processing oils, processing aids, carbon black, colorants or pigments, stability control agents, nucleating agents, fillers, antioxidants, acid scavengers, ultraviolet (UV) stabilizers, flame retardants, lubricants, processing aids, extrusion aids, and combinations thereof. When present, the total amount of the additives can be more than 0 to 80%, or 0.001% to 70%, or 0.01% to 60%, or 0.1% to 50%, or 0.1% to 40%, or 0.1% to 20%, or 0.1% to 10%, or 0.1% to 5% of the total weight of the composition.

[0081] In one embodiment, the crosslinkable composition and / or the crosslinked composition contains an antioxidant. Non-limiting examples of suitable antioxidants include aromatic or hindered amines, such as alkyldiphenylamine, phenyl-α-naphthylamine, alkyl- or aralkyl-substituted phenyl-α-naphthylamine, alkylated p-phenylenediamine, tetramethyl-diaminodiphenylamine, etc., phenols, such as 2,6-di-t-butyl-4-methylphenol, 1,3,5-trimethyl-2,4,6-tris(3’,5-di-t-butyl-4,-hydroxybenzyl)benzene, tetrakis[(methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane (e.g., IRGANOX™ 1010 (Ciba Geigy, New York)), acryloyl-modified phenol, octadecyl-3,5-di-t-butyl-4-hydroxycinnamate (e.g., IRGANOX™ 1076 commercially available from Ciba Geigy), phosphites and phosphonites, hydroxylamines, benzofuranone derivatives, and combinations thereof. When used, the amount of the antioxidant in the composition can be more than 0 to 5 wt%, 0.0001 to 2.5 wt%, or 0.001 to 1 wt%, or 0.001 to 0.5 wt% of the total weight of the composition.

[0082] In one embodiment, the crosslinkable composition and / or the crosslinked composition includes a UV stabilizer. Non-limiting examples of suitable UV stabilizers include benzophenone, benzotriazole, aryl ester, oxanilide, acrylate ester, formamidine, carbon black, hindered amine, nickel quencher, hindered amine, phenolic antioxidant, metal salt, zinc compound, and combinations thereof. When used, the amount of the UV stabilizer can be more than 0 to 5 wt%, or 0.01 wt% to 3 wt%, or 0.1 wt% to 2 wt%, or 0.1 wt% to 1 wt% of the total weight of the composition.

[0083] In one embodiment, the crosslinkable composition and / or the crosslinked composition includes a colorant or pigment. Non-limiting examples of suitable colorants or pigments include inorganic pigments such as metal oxides such as iron oxide, zinc oxide, and titanium dioxide, mixed metal oxides, carbon black, organic pigments such as anthraquinone, ansanthrone, azo, and monoazo compounds, arylamide, benzimidazolone, BONA lake, diketopyrrolo-pyrrole, dioxazine, disazo compound, diarylide compound, flavanthrone, indanthrone, isoindolinone, isoindoline, metal complex, monoazo salt, naphthol, b-naphthol, naphthol AS, naphthol lake, perylene, perinone, phthalocyanine, pyranthrone, quinacridone, and quinophthalone, and combinations thereof. When used, the amount of the colorant or pigment in the composition can be more than 0 to 10 wt%, or 0.1 wt% to 5 wt%, or 0.25 wt% to 2 wt% of the total weight of the composition.

[0084] In one embodiment, the crosslinkable composition and / or the crosslinked composition contains a filler. Non-limiting examples of suitable fillers include talc, calcium, carbonate, chalk, calcium sulfate, clay, kaolin, silica, glass, fumed silica, mica, wollastonite, feldspar, aluminum silicate, calcium silicate, alumina, hydrated alumina such as alumina trihydrate, glass microspheres, barite, wood flour, glass fibers, carbon fibers, marble powder, cement powder, magnesium oxide, magnesium hydroxide, antimony oxide, zinc oxide, barium sulfate, titanium dioxide, titanates, and combinations thereof.

[0085] In one embodiment, the filler is barium sulfate, talc, calcium carbonate, silica, glass, glass fibers, alumina, titanium dioxide, or a mixture thereof. In a further embodiment, the filler is talc, calcium carbonate, barium sulfate, glass fibers, or a mixture thereof. When used, the amount of filler in the composition can be more than 0% to 80% by weight, or 0.1% to 60% by weight, or 0.5% to 40% by weight, or 1% to 30% by weight, or 10% to 40% by weight of the total weight of the composition.

[0086] In one embodiment, the crosslinkable composition and / or the crosslinked composition contains a lubricant. Non-limiting examples of suitable lubricants include fatty alcohols and their dicarboxylic acid esters, fatty acid esters of short-chain alcohols, fatty acids, fatty acid amides, metal soaps, oligomeric fatty acid esters, fatty acid esters of long-chain alcohols, montan wax, polyethylene wax, polypropylene wax, natural and synthetic paraffin waxes, fluoropolymers, and combinations thereof. When used, the amount of lubricant in the composition can be more than 0% to 5% by weight, or 0.1% to 4% by weight, or 0.1% to 3% by weight of the total weight of the composition.

[0087] In one embodiment, the crosslinkable composition and / or the crosslinked composition includes an antistatic agent. Non-limiting examples of suitable antistatic agents include conductive fillers (e.g., carbon black, metal particles, and other conductive particles), fatty acid esters (e.g., glycerol monostearate), ethoxylated alkylamines, diethanolamide, ethoxylated alcohols, alkyl sulfonates, alkyl phosphates, quaternary ammonium salts, alkyl betaines, and combinations thereof. When used, the amount of the antistatic agent in the composition can be more than 0 wt% to 5 wt%, or 0.01 to 3 wt%, or 0.1 to 2 wt% of the total weight of the composition.

[0088] H. Foamed articles In one embodiment, the crosslinkable polymer composition and / or the crosslinked composition includes a foaming agent. The foaming agent is used to foam the crosslinked composition. Foaming agents suitable for producing the foams disclosed herein can include, but are not limited to, inorganic foaming agents, organic foaming agents, chemical foaming agents, and combinations thereof.

[0089] The amount of the foaming agent in the crosslinkable polymer composition disclosed herein can be about 0.1 to about 20 wt%, about 0.1 to about 10 wt%, or about 0.1 to about 5 wt% based on the weight of the ethylene-based polymer and / or the polar ethylene-based polymer or polymer blend. In other embodiments, the amount of the foaming agent is about 0.2 to about 5.0 moles per kilogram of the interpolymer or polymer blend, about 0.5 to about 3.0 moles per kilogram of the interpolymer or polymer blend, or about 1.0 to about 2.50 moles per kilogram of the interpolymer or polymer blend.

[0090] Non-limiting examples of suitable blowing agents include inorganic physical blowing agents such as air, argon, nitrogen, carbon dioxide, helium, oxygen, and neon, and organic physical blowing agents such as aliphatic hydrocarbons, for example, propane, n-butane, isobutane, n-pentane, isopentane, and n-hexane, cycloaliphatic hydrocarbons, for example, cyclohexane, and cyclopentane, halogenated hydrocarbons, for example, chlorofluoromethane, trifluoromethane, 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane, methyl chloride, ethyl chloride, and methylene chloride, and dialkyl ethers, for example, dimethyl ether, diethyl ether, and methyl ethyl ether.

[0091] Non-limiting examples of suitable organic blowing agents include aliphatic hydrocarbons having 1 to 6 carbon atoms, aliphatic alcohols having 1 to 3 carbon atoms, and fully and partially halogenated aliphatic hydrocarbons having 1 to 4 carbon atoms. Non-limiting examples of suitable aliphatic hydrocarbons include methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, etc. Non-limiting examples of suitable aliphatic alcohols include methanol, ethanol, n-propanol, and isopropanol. Non-limiting examples of suitable fully and partially halogenated aliphatic hydrocarbons include fluorocarbons, chlorocarbons, and chlorofluorocarbons. Non-limiting examples of suitable fluorocarbons include fluorinated methyl, perfluoromethane, fluorinated ethyl, 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, dichloropropane, difluoropropane, perfluorobutane, perfluorocyclobutane. Non-limiting examples of suitable partially halogenated chlorocarbons and chlorofluorocarbons include 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), and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124). Non-limiting examples of suitable fully halogenated chlorofluorocarbons include trichloromonofluoromethane (OPOI 1), dichlorodifluoromethane (CFO-12), trichlorotrifluoroethane (CFO-113), 1,1,1-trifluoroethane, pentafluoroethane, dichlorotetrafluoroethane (CFO-114), chloroheptafluoropropane, and dichlorohexafluoropropane.

[0092] Non-limiting examples of suitable chemical blowing agents include azodicarbonamide, azodiisobutyronitrile, benzenesulfonohydrazide, 4,4-oxybenzenesulfonyl-semicarbazide, p-toluenesulfonylsemicarbazide, barium azodicarboxylate, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, and trihydrazinotriazine.

[0093] The components of the foam, namely, the polymer component, BITEMPS methacrylate, the blowing agent, and the free radical initiator and optional additives, can be mixed or blended. Non-limiting examples of suitable blending methods include melt blending, solvent blending, extrusion molding, and the like.

[0094] In some embodiments, the components of the foam are melt blended by the method described by Guerin et al. in U.S. Patent No. 4,152,189. First, all solvents, if present, are removed from the components by heating to a suitable elevated temperature of about 100°C to about 200°C or about 150°C to about 175°C at about 5 torr (667 Pa) to about 10 torr (1333 Pa). Next, the components are weighed into a container in the desired proportions, and the foam is formed by heating the contents of the container to a molten state while stirring.

[0095] In other embodiments, the components of the foam are treated using solvent blending. First, the components of the desired foam are dissolved in a suitable solvent, and then the mixture is mixed or blended. Next, the solvent is removed to obtain the foam.

[0096] In a further embodiment, a physical mixing device that can provide dispersion mixing, distributive mixing, or a combination of dispersion mixing and distributive mixing can be used to prepare a homogeneous mixture. Both batch and continuous physical mixing can be used. In some embodiments, an ethylene-based polarity and / or a polar ethylene-based polarity, peroxide, BiTEMPS, and optional additives (antioxidants, pigments, adhesion promoters, fillers, nucleating agents, rubbers, stabilizers, processing aids, activators for foaming agents), and a foaming agent can be melt blended by a Banbury mixer, an intensive mixer, a two-roll mill, and an extruder, and combinations thereof. The time, temperature, and shear rate can be adjusted to ensure dispersion without early crosslinking or foaming. After the crosslinkable polymer composition is mixed, the crosslinkable polymer composition is formed into a desired shape. A sheeting roll or a calendar roll can be used to produce a sheet appropriately sized for foaming. An extruder can be used to form the crosslinkable polymer composition into pellets.

[0097] Foaming is achieved by compression molding, injection molding, and a hybrid of extrusion and molding of the crosslinkable composition. Foaming may be carried out by placing the crosslinkable composition in a compression mold (or autoclave) at a pressure, temperature, and time sufficient to complete the decomposition of the peroxide and / or the foaming agent. The crosslinkable polymer composition can be impregnated with a foaming agent (physical foaming agent and / or chemical foaming agent) before entering the compression mold / autoclave or after the crosslinkable polymer composition has been placed in the compression mold / autoclave. Pressure and heat are applied to the compression mold / autoclave. When the compression mold / autoclave is rapidly depressurized and released, foam formation is induced. The resulting foam can be further shaped as desired by thermoforming and / or compression molding.

[0098] When using a free radical initiator, crosslinking of the foam article can be induced by activating the free radical initiator in the crosslinkable composition. The free radical initiator can be activated by exposing the free radical initiator to a temperature above its decomposition temperature. Alternatively, the free radical initiator can be activated by exposing the free radical initiator to radiation that causes the generation of free radicals from the free radical initiator. Similarly, foaming or expansion of the foam article disclosed herein can be induced by activating a blowing agent in the crosslinkable composition. In some embodiments, the blowing agent is activated by exposing it to a temperature higher than its activation temperature. Generally, activation of crosslinking and foaming can occur simultaneously or sequentially. In some embodiments, the activation occurs simultaneously. In other embodiments, activation of crosslinking occurs first, followed by activation of foaming. In further embodiments, activation of foaming occurs first, followed by activation of crosslinking.

[0099] The crosslinkable polymer composition can be prepared or processed at a temperature below 150 °C to prevent decomposition of the blowing agent and the free radical initiator. When using radiation crosslinking, the crosslinkable polymer composition can be prepared or processed at a temperature below 160 °C to prevent decomposition of the blowing agent. In some embodiments, the crosslinkable polymer composition can be extruded or processed through a die of a desired shape to form a crosslinkable structure. The crosslinkable structure can then be expanded and crosslinked at a high temperature (e.g., about 150 °C to about 250 °C) to activate the blowing agent and the free radical initiator to form a foam structure. In some embodiments, the foamable structure can be irradiated to crosslink the polymer material, and then the polymer material can be expanded at a high temperature as described above.

[0100] The foam articles disclosed herein can be prepared by conventional extrusion foaming processes. The foam articles generally involve heating an ethylene polymer and / or a polar ethylene polymer or polymer blend to form a plasticized or molten polymer material, incorporating a blowing agent therein to form a crosslinkable composition, and preparing the crosslinkable composition by extruding it through a die to form a foam product. Before mixing with the blowing agent, the ethylene polymer and / or polar ethylene polymer can be heated to a temperature above its glass transition temperature or melting point. The blowing agent can be incorporated into or mixed with the molten ethylene polymer and / or polar ethylene polymer using an extruder, mixer, blender, etc. The blowing agent can be mixed with the molten ethylene polymer and / or polar ethylene polymer at a high pressure sufficient to prevent substantial expansion of the molten ethylene polymer and / or polar ethylene polymer and to roughly disperse the blowing agent uniformly therein. Optionally, before plasticization or melting, a nucleating agent can be blended into the interpolymer melt or dry blended with the ethylene polymer and / or polar ethylene polymer. The crosslinkable polymer composition can be cooled to a lower temperature to optimize the physical properties of the foam structure. The crosslinkable polymer composition can then be extruded or conveyed through a die of a desired shape into a zone of reduced pressure or a lower pressure to form a foam structure. The zone of lower pressure can be at a pressure lower than the pressure maintained before the crosslinkable polymer composition is extruded through the die. The lower pressure can be superatmospheric or subatmospheric (vacuum), but is preferably at the atmospheric pressure level.

[0101] The foams or crosslinkable compositions disclosed herein can have a density of 150 to about 600 kg / m, 150 to about 500 kg / m, 150 to about 400 kg / m, 150 to about 350 kg / m, about 150 to about 300 kg / m, or about 150 to about 250 kg / m. In some embodiments, the foams disclosed herein have a density of 150 to about 500 kg / m. In other embodiments, the foams disclosed herein have a density of 175 to about 500 kg / m. In further embodiments, the foams disclosed herein have a density of 200 to about 500 kg / m.

[0102] The foaming process forms a foam article. The foam article is composed of a crosslinked foam composition. The crosslinked foam composition includes an ethylene polymer and / or a polar ethylene polymer, BiTEMPS, and optional additives. In some embodiments, the foam articles disclosed herein can have an average cell size of 0.05 to 5.0 g / cc, 0.2 to 2.0 g / cc, 0.1 to 1.5 g / cc, 0.1 to 1.0 g / cc, or 0.2 to 0.6 g / cc in accordance with ASTM D3576. In some embodiments, the crosslinked foam composition has uniform, independent foamed cells and has a density of less than 0.2 g / cc, or 0.05 g / cc to 0.2 g / cc, or 0.05 g / cc to 0.15 g / cc.

[0103] In an embodiment, the foam article is a crosslinked foam composition composed of an ethylene polymer, a bond of Structure 2 (formed from BiTEMPS), and optional additives. The ethylene polymer is an ethylene / octene multi-block copolymer. The crosslinked foam composition has uniform, independent foamed cells. The crosslinked foam composition is (i) 50 wt% to 99 wt% of an ethylene / octene multi-block copolymer, wherein (a) having a density of 0.850 g / cc to 0.905 g / cc, and (b) having an MI of 0.2 g / 10 min to 100 g / 10 min, the ethylene / octene multi-block copolymer, (ii) Bonding of Structure 2 (formed from 1 wt% to 15 wt% of BiTEMPS methacrylate), (iii) 0 wt%, or 0.1 wt% to 1.0 wt% of an additive, comprising, consisting essentially of, or consisting of these, and the assembly of the ethylene-based polymer and the bonding of Structure 2 (formed from BiTEMPS methacrylate) (and optional additive) is 100 wt% of the crosslinked foam composition, and the crosslinked foam composition has the following properties: (iv) A density of 0.05 g / cc to 0.3 g / cc, and / or 0.08 g / cc to 0.25 g / cc, and / or 0.1 g / cc to 0.2 g / cc, (v) A tensile strength of 0.7 MPa to 4 MPa, and / or 1 MPa to 3 MPa, and / or 1.5 MPa to 2.8 MPa, (vi) A rebound of 40% to 90%, and / or 50% to 80%, and / or 55% to 75%, (vii) A hardness (Asker C) of 5 to 60, having one, several, or all of these.

[0104] In one embodiment, the foam article is a crosslinked foam composition composed of a polar ethylene-based polymer, a bonding of Structure 2 (formed from BiTEMPS), and an optional additive. The crosslinked foam composition has uniform, independent foam cells and has a density of less than 0.2 g / cc, or 0.05 g / cc to 0.2 g / cc, or 0.05 g / cc to 0.15 g / cc.

[0105] In an embodiment, the foam article is a crosslinked foam composition composed of a polar ethylene-based polymer, a bonding of Structure 2 (formed from BiTEMPS), and an optional additive. The polar ethylene-based polymer is ethylene vinyl acetate. The crosslinked foam composition has uniform, independent foam cells. The crosslinked foam composition (i) Is 5 wt% to 100 wt% ethylene vinyl acetate, (a) Having a density of 0.921 g / cc to 0.965 g / cc, (b) Ethylene vinyl acetate having an MI of 0.3 g / 10 min to 500 g / 10 min, (c) Vinyl acetate having a vinyl acetate content of 1% to 40% by weight (based on the total weight of ethylene vinyl acetate), ethylene vinyl acetate, (ii) Bond of Structure 2 (formed from 1% to 15% by weight of BiTEMPS methacrylate), (iii) Contains 0% by weight, or 0.1% to 1.0% by weight of an additive, consists essentially of these, or consists of these, and the aggregate of the ethylene-based polymer and the bond of Structure 2 (formed from BiTEMPS methacrylate) (and optional additives) is 100% by weight of the crosslinked foam composition.

[0106] The foams disclosed herein may take any physical form such as spheres, cylinders, discs, cubes, prisms, sheets, slabs, foam slab stock, or irregular shapes. Further, they can be injection molded articles, compression molded articles, or extruded molded articles. Other useful forms are expandable or crosslinkable particles, moldable foam particles or beads, and articles formed by expansion and / or coalescence and welding of these particles. Non-limiting examples of suitable foam articles include footwear (e.g., midsole of footwear), packaging, sports goods, building materials, and insulation materials.

[0107] In some footwear applications such as inner soles, mid soles, outer soles, unit soles, and insoles, the foams disclosed herein can be substantially crosslinked. A foam is substantially crosslinked when the foam contains more than 5% gel according to ASTM D - 2765 - 84 Method A. In some embodiments, the foams disclosed herein contain more than about 5% gel, more than about 10% gel, more than about 15% gel, more than about 20% gel, more than about 25% gel, more than about 30% gel, more than about 35% gel, or more than about 40% gel according to ASTM D - 2765 - 84 Method A. In other embodiments, the foams disclosed herein contain less than about 95% gel. In further embodiments, the foams disclosed herein contain less than about 85% gel. In further embodiments, the foams disclosed herein contain less than about 75% gel.

[0108] I. Recyclability BiTEMPS methacrylate is a "dynamic crosslinking agent". The dynamic crosslinking agent BiTEMPS methacrylate enables the formation of a crosslinked ethylene-based polymer network by means of disulfide bonds between the chains of an ethylene-based polymer (in the presence of a free radical initiator) to form a crosslinked ethylene-based polymer composition. When the crosslinked ethylene-based polymer composition is subjected to a "reprocessing temperature" which is a temperature of 130°C to 300°C, or 140°C to 280°C, or 150°C to 270°C, or 160°C to 255°C, the disulfide bonds can be broken, enabling chain mobility and exchange, so the crosslinking is dynamic. At the reprocessing temperature, the disulfide bonds in the crosslinked ethylene-based polymer composition are broken, forming a reprocessable ethylene-based polymer composition. When the reprocessable ethylene-based composition is cooled below the reprocessing temperature, a re-crosslinked ethylene-based polymer composition is formed.

[0109] The dynamic crosslinking agent BiTEMPS methacrylate enables periodic "reprocessing" for the secondary fabrication of new polymer articles. When the crosslinked ethylene-based polymer composition is heated to the reprocessing temperature, the disulfide bonds are broken or otherwise cleaved, allowing the previously crosslinked ethylene-based polymer composition to flow at the reprocessing temperature and form a "reprocessable ethylene-based polymer composition". Heating to the reprocessing temperature allows bond breakage and polymer chain flow, enabling the ethylene-based composition to be easily reshaped. At the reprocessing temperature, the reprocessable ethylene-based polymer composition is no longer crosslinked but rather is fluid, now allowing the fluid reprocessable ethylene-based composition (including BiTEMPS methacrylate) to be molded and / or secondary processed into a new preform or article. Cooling below the "reprocessing temperature" reforms the disulfide bonds, reconstructs the network, and forms a newly crosslinked ethylene-based composition in a new article configuration, returning to the high viscosity (non-flowing at room temperature) and resistance to mechanical deformation characteristic of the crosslinked network. When the newly formed article of the reprocessable ethylene-based polymer composition is cooled below the reprocessing temperature, the disulfide bonds in the reprocessable ethylene-based polymer composition are reconstructed, and the ethylene-based polymer (including BiTEMPS methacrylate) becomes a newly crosslinked ethylene-based polymer composition assuming the shape of the secondary processed article. Below the reprocessing temperature, the network disulfide bonds are stable, and the newly crosslinked ethylene-based polymer composition exhibits the high viscosity characteristic of the crosslinked network and resistance to mechanical deformation. This cycle of crosslinking / reprocessing / recrosslinking and secondary processing into new articles can be repeated.

[0110] Although not bound by a particular theory, the number of “reprocessing” cycles that are possible using the present crosslinked ethylene-based composition (before competing heat and oxidative permanent crosslinking occur and prevent further reprocessing) can be determined by calculating the ratio of the melt viscosities of the crosslinked ethylene-based polymer composition before and after the reprocessing cycle. For a crosslinked ethylene-based polymer composition that is reprocessable, the ratio of the Mooney viscosity after reprocessing to the Mooney viscosity before reprocessing is from 0.5 to 5, or from 0.7 to 3, or from 0.9 to 2, or from 0.95 to 1.2.

[0111] Another measurement criterion for monitoring the number of “reprocessing” cycles that are possible using a BiTEMPS methacrylate dynamic crosslinking agent before competing oxidative permanent crosslinking occurs is visual observation. A formed film that has been mechanically deformed is heated to the reprocessing temperature and visually inspected to determine whether the mechanically deformed film recovers to form a stable film.

[0112] The present disclosure provides a process. In one embodiment, the process is It includes heating the foam article to a reprocessing temperature. The foam article is composed of a cross-linked foam composition composed of (i) an ethylene-based polymer and / or a polar ethylene-based polymer, (ii) a bond of Structure 2 (formed from 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate)), and (iii) an optional additive. The process includes forming the foam article into a reprocessable polymer composition (a reprocessable ethylene-based polymer or a reprocessable polar ethylene-based polymer) at the reprocessing temperature. The process includes shaping the reprocessable polymer composition (a reprocessable ethylene-based polymer composition or a reprocessable polar ethylene-based polymer composition) into a reprocessed preform at the reprocessing temperature. The process includes cooling the reprocessed preform to a temperature below the reprocessing temperature and forming a second article composed of a re-crosslinked polymer composition composed of (i) an ethylene-based polymer and / or a polar ethylene-based polymer and (ii) a bond of Structure 2 (formed from BiTEMPS methacrylate).

[0113] The second article may be the same as or different from the first article.

[0114] In one embodiment, the shaping step is a procedure selected from the group consisting of injection molding, extrusion molding, thermoforming, slush molding, overmolding, insert molding, blow molding, cast molding, tentering, compression molding, and combinations thereof.

[0115] Non-limiting examples of articles (second articles) suitable for the present crosslinked (polar) ethylene-based polymer composition (including BiTEMPS methacrylate) include foamed articles, elastic films, elastic fibers, soft-touch items such as toothbrush handles and instrument handles, gaskets and profiles, three-dimensional loop materials, coatings for conductors, adhesives (including hot melt adhesives and pressure-sensitive adhesives), footwear (including shoe soles and shoe liners), automotive interior parts and profiles, foamed articles (both open-cell and closed-cell foams), impact modifiers for other thermoplastic polymers, such as high-density polyethylene, isotactic polypropylene, or other olefin polymers, coated fabrics, hoses, tubes, overlays, cap liners, flooring materials, and combinations thereof.

[0116] Another embodiment provides a process for reprocessing a foamed article. In one embodiment, the reprocessing includes converting the foam into small pieces, mixing optional additives into the small pieces, heating the mixed product to a reprocessing temperature, or a combination of the above methods. The conversion process includes pressing, calendering, cutting, shearing at low temperature, room temperature, or high temperature, or a combination of the above processes. A foamed composition comprising (i) an ethylene-based polymer and / or a polar ethylene-based polymer, (ii) a bond of Structure 2 (formed from 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate)), and (iii) optional additives. The process includes cooling the reprocessed preform to below the reprocessing temperature and forming a second article composed of a crosslinked polymer composition comprising (i) an ethylene-based polymer and / or a polar ethylene-based polymer, and (ii) a bond of Structure 2 (formed from BiTEMPS methacrylate).

[0117] By way of example and not limitation, some embodiments of the present disclosure will now be described in detail in the following examples.

[0118] 1. Materials The materials used in the comparative sample (CS) and the inventive examples (IE) of the present invention are provided in Table 1 below.

[0119]

Table 1

[0120] 2. Synthesis of BiTEMPS Methacrylate To synthesize BiTEMPS methacrylate, 2,2,6,6 - tetramethyl - 4 - piperidyl methacrylate (8.78 g, 39.0 mmol, supplied by TCI America) is first dissolved in anhydrous petroleum ether (about 90 mL, supplied by Sigma - Aldrich and dried with molecular sieves for 48 hours before use) and cooled to - 70 °C in a dry ice / acetone bath. Then, sulfur monochloride (1.30 g, 9.7 mmol, supplied by Sigma - Aldrich) is dissolved in anhydrous petroleum ether (about 1.25 mL) and added dropwise to the reaction vessel over 30 minutes. The solution is stirred at - 70 °C for an additional 30 minutes and at room temperature for 15 minutes. Next, the reaction solution is poured into a large amount of distilled water and stirred overnight at room temperature to precipitate BiTEMPS methacrylate. The precipitate is collected, vacuum filtered, and dried under vacuum at 60 °C for 48 hours to obtain BiTEMPS methacrylate shown as Structure 1 below.

[0121]

Chemical formula

[0122] 3. Formulation - Crosslinkable Composition A. Inventive Examples of the Present Invention INFUSE 9000 (or EVA 265), dicumyl peroxide, and BiTEMPS methacrylate were combined (in the amounts shown in Table 2 below) and batch - mixed at 100 °C. The properties are provided in Table 2 below.

[0123] B. Comparative Samples 400 g of INFUSE pellets and 4 g of DCP powder were loaded into a PTFE bottle. The bottle was sealed and placed on a roller at a rotational speed of 65 RPM. Then, the roller was transferred to a hot air oven at 55 °C for 2 hours. After the desired time was reached, the roller was stopped, the bottle was removed from the oven, and cooled to room temperature.

[0124] After mixing, each formulation was transferred to a mold measuring 172 mm × 172 mm × 7 mm. The mold was further placed in a hot press. The hot press was preheated at 125 °C for 3 minutes and then degassed 8 times. Subsequently, the mold was transferred to a second hot press at 180 °C. In the second hot press, the mold was pressed at 180 °C and a pressure of 280 kiloNewton (kN) for 10 minutes to cure and then cooled to 45 °C. Then, the pressure was removed to form a crosslinked composition. Each crosslinked composition was fed into an autoclave equipped with a heating unit and a gas injection valve. The autoclave was heated to the desired temperature (120 - 150 °C). At the same time, a blowing agent was injected into the autoclave to saturate it (0.5 - 2 hours). The pressure of the autoclave varied depending on the type of polymer. The pressure of the autoclave was 50 bar to 200 bar. After the crosslinked composition was saturated with the blowing agent, a rapid decompression occurred and a foam slab was prepared. The foam slab was conditioned at room temperature for 24 hours. The corresponding properties are summarized in Table 2.

[0125]

Table 2

[0126] 4. Recyclability A. The selected crosslinked compositions in Table 2 were tested for reprocessability. The crosslinked compositions were manually cut into small pieces using scissors. The small pieces were transferred to a mold with dimensions of 120 mm × 75 mm × 3 mm and reprocessed for 10 minutes under a pressure of 280 KN at different temperatures. The results are reported in Table 3 below.

[0127]

Table 3

[0128] Figure 1 shows photographs of non-reprocessable comparative samples: CS-3 reprocessing 180, CS-3 reprocessing 250, and IE-3 reprocessing 130. Figure 1 shows photographs of reprocessable examples, IE-3 reprocessing 180 and IE-3 reprocessing 250.

[0129] B. Figures 3A and 3B are photographs showing IE-A foam and IE-B foam, respectively. The IE-A foam and IE-B foam were each manually cut into small pieces using scissors. The small pieces were transferred to a mold and compression molded at 40,000 psi for 2 minutes at 180 °C. Figures 4A and 4B show the IE-A foam and IE-B foam, respectively, as reprocessed uniform compression molded disks, thereby showing that the IE-A foam and IE-B foam are each completely reprocessable.

[0130] 5. Preparation of Recycled Foam The reprocessed compositions (from Table 3) were foamed under the same conditions as described in paragraph

[0096] . The properties of the foam are provided in Table 4 below.

[0131]

Table 4

[0132] Figure 2 shows photographs of the foams: CS-3 foam, IE-3 foam, IE-3 reprocessing 180 foam, and IE-3 reprocessing 250 foam.

[0133] The present disclosure is not limited to the embodiments and examples included herein, and is particularly intended to include modified forms of those embodiments, including parts of the embodiments and combinations of elements of different embodiments, to the extent that they fall within the scope of the following claims.

Claims

1. A foamed article, a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate), a foamed article comprising a crosslinked foamed composition formed from a starting material containing the same.

2. The crosslinked foamed composition, a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and a bond having structure (2), the foamed article according to claim 1 【Chemical 1】

3. The foamed article according to claim 1 or 2, wherein the polymer is an ethylene-based polymer.

4. The foamed article according to claim 3, wherein the ethylene-based polymer is an ethylene / α-olefin multiblock copolymer.

5. The crosslinked composition, 50% to 99% by weight of the ethylene / α-olefin multiblock copolymer, and 1% to 15% by weight of the BiTEMPS (methacrylate), the foamed article according to claim 4, formed from a starting material containing the same.

6. The foamed article according to claim 2, wherein the polymer is a polar ethylene-based polymer.

7. The foamed article according to claim 6, wherein the polar ethylene-based polymer is ethylene vinyl acetate.

8. The crosslinked composition, 50% to 99% by weight of the ethylene vinyl acetate, and 1% to 15% by weight of the BiTEMPS (methacrylate), the foamed article according to claim 7, formed from a starting material containing the same.

9. The foamed article, having a density of 0.05 g / cc to 0.3 g / cc, a tensile strength of 0.7 MPa to 4 MPa, a rebound of 40% to 90%, a hardness (Asker C) of 5 to 60, and the foamed article according to any one of claims 1 to 8, having a property selected from the group consisting of combinations thereof.

10. A foamed article, a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, and a crosslinked composition containing a bond having structure (2), a foamed article [Chemical Formula 2]

11. A process, a foamed article, wherein the foamed article, (i) a polymer selected from the group consisting of an ethylene-based polymer, a polar ethylene-based polymer, and combinations thereof, heating the foam article, which is composed of a crosslinked composition comprising a bond having structure (2), to a reprocessing temperature [Chemical Formula 3] forming the foam article at the reprocessing temperature into a reprocessable polymer composition molding the reprocessable polymer composition at the reprocessing temperature into a reprocessed preform cooling the reprocessed preform to a temperature below the reprocessing temperature (i) a polymer selected from the group consisting of the ethylene-based polymer, the polar ethylene-based polymer, and combinations thereof, and (ii) forming a second article composed of a re-crosslinked polymer composition composed of a bond having structure (2), the process comprising Claims 12 The process according to claim 11, wherein the polymer is an ethylene-based polymer Claims 13 The process according to claim 11, wherein the polymer is a polar ethylene-based polymer

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