Process for a Reversible Crosslinking Composition

Abstract

The present disclosure provides a process. In one embodiment, the process includes providing a crosslinkable polymer composition. The crosslinkable polymer composition includes (i) a (polar) ethylene-based polymer having a melting temperature Tm, (ii) a free radical initiator having a decomposition temperature T decomp and (iii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEM-PS methacrylate), and an optional additive. The process includes mixing the crosslinkable polymer composition in a mixing device at a temperature above the decomposition temperature of the peroxide and forming a BiTEMPS methacrylate-grafted (polar) ethylene-based polymer (BIT-g-pPE).

Description

Technical Field

[0001] Crosslinked olefin polymers (and in particular crosslinked ethylene polymers) are well known in numerous applications due to their excellent mechanical properties, high thermal stability, and remarkable chemical resistance. Unfortunately, crosslinked ethylene polymers (also known as thermoset polymers) cannot be reprocessed and / or reused due to the presence of a permanent crosslinked network within the ethylene polymer. Thus, the use of crosslinked ethylene polymers is accompanied by associated environmental and sustainability concerns.

[0002] The ability to reprocess and / or reuse crosslinked ethylene polymers has been a long-standing challenge. Thus, the art recognizes the need for crosslinked olefin polymers (in particular crosslinked ethylene polymers) that can be reprocessed and / or reused.

Summary of the Invention

[0003] The present disclosure provides a process. In one embodiment, the process includes providing a crosslinkable polymer composition. The crosslinkable polymer composition includes (i) a (polar) ethylene polymer having a melt temperature Tm, (ii) a free radical initiator having a decomposition temperature T decomp and (iii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate), and optional additives. The process includes mixing the crosslinkable polymer composition at a temperature above the decomposition temperature of the peroxide in a mixing device and forming a BiTEMPS methyl acrylate grafted (polar) ethylene polymer (BiT-g-pPE).

[0004] 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 there is a conflicting description, unless it is implicit from the context, or unless it is not customary in the art, all parts and percentages are by weight. For the purposes of United States patent practice, the contents of any patent, patent application, or publication referenced herein are hereby incorporated by reference in their entirety (or, their equivalent U.S. versions are so incorporated by reference).

[0005] The numerical ranges disclosed in this specification include all values (including the boundary values) from the lower limit to the upper limit. In the case of a range that includes 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.).

[0006] Unless there is a conflicting description, unless it is implicit from the context, or unless it is 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.

[0007] 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. 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 any ambiguity, all compositions claimed through the use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless there is a contradictory description. In contrast, the term "consisting essentially of" excludes any other components, steps, or procedures from the scope of any preamble, except for those that are not essential to the practicability. The term "consisting of" excludes any component, step, or procedure that is not specifically depicted or listed.

[0008] "Ethylene polymer" is a polymer having more than 50 mol% of polymerized ethylene monomer (based on the total amount of polymerizable monomers) and optionally containing 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), ethylene / α-olefin multiblock 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, heteroaryl, heterovalent aryloxy ethers, phosphine imines, and other homogeneous catalyst systems containing ligand structures, 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 multi-reactor configuration.

[0009] "Ethylene plastomer / elastomer" means units derived from ethylene and at least one C3-C 10It is a substantially linear or linear ethylene / α-olefin interpolymer containing a homogeneous short-chain branching distribution including units derived from an α-olefin comonomer. 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™ polyolefin plastomer and ENGAGE™ polyolefin elastomer (available from The Dow Chemical Company), EXACT™ plastomer (available from ExxonMobil Chemical), Tafmer™ alpha-olefin copolymer (available from Mitsui), Solumer™ polyolefin elastomer and Supreme™ polyolefin plastomer (available from SK Chemicals Co.), and Lucene™ polyolefin elastomer (available from LG Chem Ltd.).

[0010] "High density polyethylene" (or "HDPE") is an ethylene homopolymer, or an ethylene / α-olefin copolymer having at least one C4-C 10 α-olefin comonomer or C4-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. A "unimodal ethylene copolymer" is an ethylene / C4-C α-olefin copolymer having one distinct peak in gel permeation chromatography (GPC) showing the molecular weight distribution. 10 An α-olefin copolymer. A "multimodal ethylene copolymer" is an ethylene / C4-C α-olefin copolymer having at least two different peaks in GPC showing the molecular weight distribution. 10It is an α-olefin copolymer. Examples of multimodality include copolymers having two peaks (bimodal) and copolymers having three or more peaks. Non-limiting examples of HDPE include DOW (trademark) high-density polyethylene (HDPE) resin (commercially available from The Dow Chemical Company), ELITE (trademark) enhanced polyethylene resin (commercially available from The Dow Chemical Company), CONTINUUM (trademark) bimodal polyethylene resin (commercially available from The Dow Chemical Company), LUPOLEN (trademark) (commercially available from LyondellBasell), and HDPE products from Borealis, Ineos, and ExxonMobil.

[0011] 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, and having a heterogeneous 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 (trademark) linear low density polyethylene resin (available from The Dow Chemical Company), DOWLEX (trademark) polyethylene resin (available from the Dow Chemical Company), and MARLEX (trademark) polyethylene (available from Chevron Phillips).

[0012] 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 (above 100 MPa (e.g., 100 - 400 MPa), in a tubular reactor or an autoclave reactor using a free radical initiator). LDPE resins typically have a density in the range of less than 0.915 - 0.940 g / cc. LDPE is different from LLDPE.

[0013] As used herein, an "olefinic polymer" or "polyolefin" is a polymer that contains more than 50 mole percent polymerized olefin monomers (based on the total amount of polymerizable monomers), and optionally may contain at least one comonomer. Non-limiting examples of olefinic polymers include ethylene-based polymers and propylene-based polymers.

[0014] A "polymer" is a compound prepared by polymerizing a plurality of monomers that provide the "units" or "mer units" that make up the polymer, whether of the same or different types, and / or repeating. Thus, the general term "polymer" encompasses the term "homopolymer", which is usually used to refer to a polymer prepared from only one type of monomer, and the term "copolymer", which is usually used to refer to a polymer prepared from at least two types of monomers. It also encompasses all forms of copolymers, such as random, block, etc. The terms "ethylene / α-olefin polymer" and "propylene / α-olefin polymer" each refer to the above-described copolymers prepared by polymerizing ethylene or propylene with one or more additional polymerizable α-olefin monomers. Polymers are often referred to as being "made of", "based on", "containing" a specific monomer content of one or more specific monomers, etc., but in this context, it should be noted that the term "monomer" is understood to refer to the polymerized residue of a specific 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.

[0015] Test Methods Compression molded specimens are formed at a molding pressure of 180 °C and 10 MPa for 5 minutes and then quenched for 2 minutes between cooling platens (15 °C to 20 °C) or as otherwise described herein.

[0016] Density is measured in accordance with ASTM D792 and the results are reported in g / cc at 25 °C. Dynamic mechanical analysis (DMA). The DMA experiment was carried out using a TA Instruments RSA-G2 Solid Analyzer, and the storage modulus (G'), loss modulus (G''), and damping ratio (tanδ) of the network were measured as functions of temperature and reuse under a nitrogen atmosphere. DMA was operated in tension mode at a frequency of 1 Hz with a vibration strain of 0.03%. Data were collected from room temperature to 160 °C at a heating rate of 3 °C / min.

[0017] The heat distortion temperature (HDT) was measured using the ASTM D648 method. The temperature at which the sample deformed was reported for loads of 0.455 MPa and 1.82 MPa.

[0018] (Ethylene-based polymer) The melt index (MI or I2) was measured according to ASTM D 1238 under the conditions of 190 °C / 2.16 kg, and the results were reported in grams per 10 minutes (g / 10 min). 21 I was measured according to ASTM D 1238 under the conditions of 190 °C / 21.6 kg, and the results were reported in grams per 10 minutes (g / 10 min).

[0019] The rheological analysis was performed using a Rubber Process Analyzer (RPA). The rheology of the composition was measured using a rotorless oscillatory shear rheometer, Alpha Technologies RPA 2000 instrument, according to ASTM D6204, under the following test conditions and exceptions. For the analysis, the sample was placed between two Mylar films. Rheology was monitored during an initial 60-minute (minute) test at 180 °C, 1.0 rad / s, and 7% strain. The elastic torque S’ at the end of the 60-minute (minute) (min) crosslinking process was recorded. Immediately after 60 minutes at 160 °C, a frequency sweep from 0.1 to 300 rad / s was performed on the same sample at 180 °C and 7% strain, then a frequency sweep from 0.1 to 300 rad / s was performed at 190 °C and 7% strain, and then a frequency sweep from 0.1 to 300 rad / s was performed at 230 °C and 7% strain. The dynamic complex viscosity n*, and tan delta were recorded for each frequency sweep. In ASTM D6204, the frequency sweep for the unvulcanized rubber is performed before the curing process. In this case, the frequency sweep was performed after the first crosslinking step at 180 °C to evaluate the reversibility of crosslinking. The viscosity temperature reprocessing ratio (or “VRR”) is defined as follows.

[0020] VRR is the ratio of n* at 0.1 rad / s and 180 °C to n* at 0.1 rad / s and 230 °C. Thermomechanical analysis (penetration temperature) is performed on a compression molded disk with a diameter of 30 mm × thickness of 3.3 mm, formed at 180 °C and a molding pressure of 10 MPa for 5 minutes and then air quenched. The instrument used is a TA Instruments TMA400 thermomechanical analyzer. In the test, a 1.5-mm probe is applied to the surface of the sample disk with a force of IN. The temperature is increased from 25 °C at 5 °C / min. Probe penetration is measured as a function of temperature. The experiment is terminated when the probe has penetrated 1000 mm (1 mm) into the sample.

[0021] The Vicat softening point is measured using ASTM D1525. Report the temperature at which a needle with a flat tip penetrates the sample to a thickness of 1 mm when a load of 10 N is applied.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0023] The present disclosure provides a process. In one embodiment, the process includes providing a crosslinkable polymer composition. The crosslinkable polymer composition includes (i) a (polar) ethylene-based polymer having a melting temperature Tm, (ii) a free radical initiator having a decomposition temperature T decomp and (iii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate), and optional additives. The process includes mixing the crosslinkable polymer composition at a temperature above the decomposition temperature of the peroxide in a mixing device and forming a BiTEMPS methyl acrylate grafted (polar) ethylene-based polymer (BiT-g-pPE).

[0024] A. (Polar) Ethylene-Based Polymer The blend component includes a (polar) ethylene-based polymer. As used herein, "(polar) ethylene-based polymer" is (i) a polar ethylene-based polymer, (ii) an ethylene-based polymer, or (iii) a combination of (i) and (ii). 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, the 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 copolymers 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. Further 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 copolymer (EMAVTMS), ethylene / ethyl acrylate / vinyl(trimethoxy)silane terpolymer copolymer (EEAVTMS), ethylene / butyl acrylate / vinyl(trimethoxy)silane terpolymer copolymer (EBAVTMS), ethylene / methyl acrylate / glycidyl methacrylate (EMAGMA), ethylene / butyl acrylate / glycidyl methacrylate (EBAGMA), ethylene / vinyl acetate / maleic anhydride terpolymer (EEAMAH), ethylene ethyl acrylate / maleic anhydride (EEAMAH) terpolymer, and combinations thereof.

[0025] In one embodiment, the polar ethylene-based polymer is an ethylene / vinyl acetate copolymer. (Polar) ethylene-based polymers can be ethylene-based polymers. "Ethylene-based polymers", as used herein, are hydrocarbons and thus different from polar ethylene-based polymers containing heteroatoms. Ethylene-based polymers can be ethylene homopolymers, ethylene / α-olefin interpolymers, or ethylene / C4-C 20 α-olefin copolymers. In embodiments herein, ethylene-based comprises units derived from ethylene in an amount greater than 50 wt% (based on the total amount of polymerizable monomers) and units derived from one or more α-olefin comonomers in an amount less than 30 wt%. All individual values and subranges of units derived from ethylene in an amount greater than 50 wt% and units derived from one or more α-olefin comonomers in an amount less than 30 wt%. Suitable α-olefin comonomers typically have 20 or fewer carbon atoms. For example, the α-olefin comonomer can have 3 to 10 carbon atoms, or 3 to 8 carbon atoms. Exemplary α-olefin comonomers include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 4-methyl-1-pentene. One or more α-olefin comonomers can be selected, for example, from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene, or alternatively from the group consisting of 1-butene, 1-hexene, and 1-octene, or alternatively from the group consisting of 1-hexene and 1-octene. In some embodiments, the ethylene-based polymer comprises units derived from one or more of 1-octene, 1-hexene, or 1-butene comonomer in an amount greater than 0 wt% to less than 30 wt%.

[0026] 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. In the embodiments of this specification, the ethylene-based polymer has a density in the range of 0.854 to 0.925 g / cc. All individual values and sub-ranges from 0.854 to 0.925 g / cc are included and disclosed herein. In some embodiments, the ethylene-based composition may have a density of 0.895 to 0.925 g / cc, 0.900 to 0.925 g / cc, 0.900 to 0.920 g / cc, 0.900 to 0.915 g / cc, 0.900 to 0.912 g / cc, 0.900 to 0.911 g / cc, or 0.900 to 0.910 g / cc. In further specific embodiments, the ethylene-based polymer composition may have a density of 0.875 to 0.925 g / cc, 0.890 to 0.925 g / cc, 0.900 to 0.925 g / cc, 0.903 to 0.925 g / cc, or 0.905 to 0.925 g / cc. The density can be measured in accordance with ASTM D792.

[0027] Non-limiting examples of suitable ethylene-based polymers include ethylene / α-olefin interpolymers, high density polyethylene (“HDPE”), linear low density polyethylene (“LLDPE”), low density polyethylene (“LDPE”), and combinations thereof.

[0028] In one embodiment, the ethylene / α-olefin interpolymer is an ethylene / C4-C8 α-olefin copolymer having one, some, or all of the following characteristics: (i) octene comonomer, and / or (ii) a density of 0.860 g / cc to 0.925 g / cc, or 0.880 g / cc to 0.920 g / cc, or 0.899 g / cc to 0.915 g / cc, or 0.899 g / cc to 0.910 g / cc, and / or (iii) A melt index of 0.5 g / 10 min to 100 g / 10 min, or 1 g / 10 min to 30 g / 10 min, or 2 g / 10 min to 20 g / 10 min. Preferred ethylene / C 4- Non-limiting examples of C8α-olefin copolymers include ENGAGE™ 8450 POE, ENGAGE™ 8402 POE, ENGAGE™ 8401 POE, ELITE™ 5815 enhanced polyethylene resin, ELITE™ 5220 enhanced polyethylene resin, or blends thereof.

[0029] 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 / C3-C8α-olefin multi-block copolymer composed of polymerized forms of ethylene and one copolymerizable C3-C8α-olefin comonomer or C4-C8α-olefin comonomer (and optional additives), and the polymer is characterized by a plurality of blocks or segments of two polymerized monomer units having different chemical or physical properties, and the blocks are joined (or covalently bonded) in a linear fashion, which means that the polymer contains chemically distinct units with ends 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 C3-C8α-olefin is selected from propylene, butene, hexene, and octene. The ethylene / α-olefin multi-block copolymer does not contain styrene (i.e., does not contain styrene), 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) ncan 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 sub-blocks) of distinct compositions, such as a tip segment having a composition substantially different from the remaining blocks.

[0030] In one embodiment, ethylene constitutes a majority molar fraction of the total ethylene / α-olefin multiblock copolymer, that is, 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 remaining portion of the ethylene / α-olefin multiblock copolymer containing a C3-C8 α-olefin comonomer or a C4-C8 α-olefin comonomer.

[0031] 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.

[0032] 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 greater than 90 wt%, or 95 wt%, or greater than 95 wt%, or greater 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 greater than 5 wt%, or greater than 8 wt%, greater than 10 wt%, or greater than 15 wt% based on the weight of the polymer. In one embodiment, the comonomer content in the soft segments is greater than 20 wt%, greater than 25 wt%, greater than 30 wt%, greater than 35 wt%, greater than 40 wt%, greater than 45 wt%, greater than 50 wt%, or greater than 60 wt%, and can be up to a maximum of 100 wt%.

[0033] The soft segment may be present in the ethylene / α-olefin multi-block copolymer in an amount of 1% to 99% by weight of the total weight of the ethylene / α-olefin multi-block copolymer, or 5% to 95% by weight, 10% to 90% by weight, 15% to 85% by weight, 20% to 80% by weight, 25% to 75% by weight, 30% to 70% by weight, 35% to 65% by weight, 40% to 60% by weight, or 45% to 55% by weight of the total weight of the ethylene / α-olefin multi-block 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. Specifically, the weight percentages and comonomer contents of the hard and soft segments can be determined as described in columns 57 to 63 of U.S. Patent No. 7,608,668.

[0034] 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 discussed in Potemkin, Physical Review E (1998) 57(6), pp. 6902-6912, and Dobrynin, J. Chem. Phys. (1997) 107(21), pp. 9234-9238.

[0035] In one embodiment, the ethylene / α-olefin multi-block copolymer has the most probable distribution of block lengths. In one embodiment, the ethylene / α-olefin multi-block copolymer is an ethylene / 1-octene multi-block copolymer (consisting only of ethylene and octene comonomers) and has one, some, or all of the following properties: (i) 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 50 to 15 wt% hard segments (based on the total weight of the ethylene / octene multi-block 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 segments, 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 segments, and / or (viii) an elastic recovery (Re) of 50% or 60% to 70%, or 80%, or 90% at a deformation rate of 300% / min at 21°C as measured according to ASTM D 1708, and / or -1 and / or (ix) Polydispersity distribution of blocks and polydispersity distribution of block sizes (hereinafter referred to as characteristics (i) to (ix) of the multiblock copolymer).

[0036] 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™ olefin block copolymer available from The Dow Chemical Company (Midland, Michigan, USA).

[0037] The ethylene / α-olefin multiblock copolymer 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 on lines 39 of column 16 to line 44 of column 19. Suitable catalysts are described on lines 45 of column 19 to line 19 of column 46, and suitable cocatalysts are described on lines 20 of column 46 to line 28 of column 51. The process is described throughout the document, but in particular on lines 29 of column 51 to line 56 of column 54. The process is also described, for example, in: U.S. Patent Nos. 7,608,668, 7,893,166, and 7,947,793.

[0038] B. Free radical initiator The crosslinkable composition contains a free radical initiator. In one embodiment, the free radical initiator is an organic peroxide. 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), isopropyl cumyl 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, isopropyl cumyl cumyl peroxide, butyl 4,4-di(tert-butylperoxy)valerate, di(isopropyl cumyl) peroxide, dicumyl peroxide, and combinations thereof.

[0039] In one embodiment, the free radical initiator is dicumyl peroxide. C.BiTEMPS methacrylate disulfide The blend component 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.

[0040] Structure 1

[0041] [Chemistry]

[0042] D. Blend Components In one embodiment, the crosslinkable polymer composition and / or the crosslinked composition comprises 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.

[0043] E. Additives The crosslinkable polymer 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.

[0044] F. Mixing The components of the crosslinkable composition ((polar) ethylene-based polymer, peroxide, and BiTEMPS) are mixed in a mixing device. In one embodiment, the crosslinkable polymer composition is 70% to 98.5% by weight, or 77% to 98.5% by weight of an ethylene-based polymer, an organic peroxide (such as dicumyl peroxide, etc.), which is 0.1% to 10% by weight, or 0.1% to 5% by weight, 0.1% to 3.0% by weight, or 0.1% to 1.5% by weight, or 0.5% to 1.5% by weight of a free radical initiator, and 1% to 20% by weight, or 1% to 15% by weight, or 2% to 20% by weight, or 2% to 10% by weight of BiTEMPS methacrylate disulfide. It is understood that the aggregate of the ethylene-based polymer, the free radical initiator, and BiTEMPS methacrylate disulfide (and optional additives) amounts to 100% by weight of the crosslinkable polymer composition.

[0045] The process includes, in a mixing device, mixing the crosslinkable composition at a temperature above the decomposition temperature of the free radical initiator (peroxide), and forming a BiTEMPS methyl acrylate grafted (polar) ethylene-based polymer (BiT-g-pPE). BiT-g-pPE includes a (polar) ethylene-based polymer (``pPE) grafted with BiTEMPS methacrylate (BiT). BiT is grafted as a pendant to the (polar) ethylene-based polymer chain. BiT forms a graft bond with the (polar) ethylene-based polymer, and the graft bond has the following Structure 3:

[0046]

Chemical formula

[0047] The term "P" (and structure) in the above structure 3 refers to the chain of (polar) ethylene-based polymerized (polar) ethylene (and optional comonomer). The ethylene-based polymer of the crosslinked composition can be any ethylene-based polymer having an MI of 0.1 g / 10 min to 100 g / 10 min, as previously disclosed herein.

[0048] In one embodiment, BiT-g-pPE is produced in a post-reactor process using an extruder. The extruder can be a single-screw extruder, a multi-screw extruder with positive and negative conveying screw elements, and a kneading / mixing plate, paddle or block with lobes.

[0049] In one embodiment, the mixing is (A) melt-blending the (polar) ethylene-based polymer over a first process period at a first temperature; (B) adding BiTEMPS and a free radical initiator to the melt-blended ethylene-based polymer of step (A) over a second process period to form a reaction mixture; (C) blending the reaction mixture over a third process period at a second temperature; (D) forming BiT-g-pPE, and includes.

[0050] The (polar) ethylene-based polymer is melt-blended in the first period. In one embodiment, the first temperature of process step (A) is the T of the (polar) ethylene-based polymer m at a temperature of ±50 °C, or ±40 °C, or ±30 °C, or ±20 °C. The first temperature is sufficient to effect complete or substantially complete melting of the (polar) ethylene-based polymer.

[0051] In one embodiment, the first temperature is a temperature of 90 °C to less than 160 °C, or 95 °C to 150 °C, or 100 °C to 140 °C, or 110 °C to 130 °C. In a further embodiment, the first temperature is from above the Tm of the (polar) ethylene-based polymer to below the T of the free radical initiator decomp up to temperature.

[0052] During the second period, BiTEMPS and the free radical initiator are added to and mixed with the molten (polar) ethylene-based polymer. In one embodiment, the first process period ends before the second process period begins.

[0053] In the third period, the second temperature is sufficient to initiate (i.e., “kick off”) the free radical initiator. In one embodiment, the second temperature in process step (C) is the T of the free radical initiator decomp is as above. In a further embodiment, the free radical initiator is a peroxide (e.g., dicumyl peroxide, etc.), and the second temperature is from 160°C to less than 180°C, or from 160°C to 179°C, or from 160°C to 175°C, or from 161°C to 173°C.

[0054] In one embodiment, steps (A)-(C) are carried out in an extruder. Alternatively, steps (A)-(C) are carried out in a batch mixing device such as a Haake™ mixing device. This process forms (D) BiT-g-pPE.

[0055] In one embodiment, the process includes collecting the BiT-g-pPE. The BiT-g-pPE can be collected as a plurality of pellets, as one or more bales, or as a combination of pellets and bales, or otherwise formed.

[0056] In one embodiment, steps (A)-(C) are completed in an extruder. In another embodiment, steps (A)-(C) are completed in a mixture such as a Haake™ mixture. In one embodiment, the ethylene-based graft polymer is prepared by reactive extrusion. Reactive extrusion is understood by those skilled in the art, such as that described in M. Xanthos, Reactive Extrusion: Principles and Practice, Hanser Publishers, Jan. 1, 1992, Technology & Engineering. In one embodiment, a co-rotating twin-screw extruder can be used. The extruder can have an L / D ratio of 36 to 60. All individual values and sub-ranges are included and disclosed. For example, the extruder can have an L / D ratio of 44 to 60, 44 to 50, or 50 to 60. Twin-screw extruders can be used in series to achieve an effective L / D ratio of 80 to 90. The extruder can have a diameter (D) of 30 to 200 mm.

[0057] The extruder can be operated at a production rate sufficient to produce at least 2,000 pounds per hour of grafted ethylene-based polymer, or at least 2,100 pounds per hour of grafted ethylene-based polymer, or at least 2,200 pounds per hour of grafted ethylene-based polymer. Those skilled in the art can interpret what is fast for different sizes of extruders.

[0058] The screw speed can be from 200 rpm to 900 rpm. The screw speed is adjusted based on the torque generated and the melt temperature. The barrel temperature in the reaction zone of the extruder can be from 160 °C to 250 °C. At the inlet of the extruder, the temperature is kept low (e.g., less than 150 °C) to avoid premature melting. Towards the end of the extruder, the temperature can be lowered to cool the melt.

[0059] G. Crosslinking In one embodiment, the process includes heating BiT-g-pPE to a crosslinking temperature of 180°C to less than 199°C, shaping the BiT-g-pPE into a preform at the crosslinking temperature, cooling the preform to below the crosslinking temperature, and forming a crosslinked article. In a further embodiment, the crosslinked article includes (i) a (polar) ethylene-based polymer and a bond having Structure 2 formed from 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate). The crosslinked article contains disulfide bonds formed from BiTEMPS methacrylate by a crosslinking reaction, and the disulfide bonds have the following Structure 2.

[0060] Structure 2

[0061] [Chemical formula]

[0062] The term "P" (and structure) in Structure 2 above refers to the chain of the polymerized (polar) ethylene (and optional comonomer) of the (polar) ethylene-based polymer. The ethylene-based polymer of the crosslinked composition can be any ethylene-based polymer having an MI of 0.1 g / 10 min to 100 g / 10 min, as disclosed previously herein.

[0063] 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.

[0064] Non-limiting examples of articles suitable for a crosslinked (polar) ethylene-based polymer composition (including the bonds of Structure 2 formed from BiTEMPS methacrylate) include elastic films, elastic fibers, soft-touch items such as toothbrush handles and appliance handles, gaskets and profiles, adhesives (including hot melt adhesives and pressure-sensitive adhesives), footwear (including shoe soles and shoe liners), automotive interior parts and profiles, foam 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, liners, cap liners, flooring materials, and combinations thereof.

[0065] H. Reprocessing BiTEMPS methacrylate is a "dynamic crosslinking agent". The dynamic crosslinking agent BiTEMPS methacrylate enables the formation of a crosslinked network of ethylene-based polymers through disulfide bonds between the chains of ethylene-based polymers. The crosslinked network is formed by an ethylene-based polymer and BiTEMPS methacrylate 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" that is a temperature of 160 °C to 230 °C, or 160 °C to 200 °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.

[0066] 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, forming 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 secondarily 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 a 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 secondarily 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 a crosslinked network and resistance to mechanical deformation. This cycle of crosslinking / reprocessing / recrosslinking to a new article can be repeated.

[0067] 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 viscosity after reprocessing to the 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.

[0068] Another measurement criterion for monitoring the number of "reprocessing" cycles that are possible using the 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.

[0069] In one embodiment, the process includes grinding a crosslinked article to form a ground material and heating the ground material to a reprocessing temperature of 180 °C to 199 °C. The process includes forming the re-ground material into a reprocessable (polar) ethylene-based polymer composition at the reprocessing temperature and shaping the reprocessable (polar) ethylene-based polymer composition into a reprocessed preform at the reprocessing temperature. The process includes cooling the reprocessed preform to below the reprocessing temperature and forming a reprocessed crosslinked article.

[0070] The reprocessed crosslinked article includes disulfide bonds formed from BiTEMPS methacrylate by a re-crosslinking reaction, and the disulfide bonds have Structure 2 below. Structure 2

[0071]

Chemical formula

[0072] Articles suitable for the reprocessed (polar) ethylene-based polymer composition (including the bond of Structure 2 formed from BiTEMPS methacrylate) include elastic films, elastic fibers, soft-touch items such as toothbrush handles and appliance handles, gaskets and profiles, adhesives (including hot melt adhesives and pressure-sensitive adhesives), footwear (including shoe soles and shoe liners), automotive interior parts and profiles, foam articles (both open-cell foams 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.

[0073] In one embodiment, the process includes heating the crosslinked article to a reprocessing temperature of 200 °C to less than 250 °C, or 200 °C to 230 °C, and forming the crosslinked article into a reprocessable (polar) ethylene-based polymer composition at the reprocessing temperature. The process includes shaping the reprocessable (polar) ethylene-based polymer composition into a reprocessed preform at the reprocessing temperature, cooling the reprocessed preform to below the reprocessing temperature, and forming the reprocessed thermoplastic article. The reprocessing temperature of 200 °C to less than 250 °C completely dissociates the disulfide bonds, thereby completely dissociating the bonds between the polymer chains in an irreversible manner. The result is a thermoplastic material.

[0074] 2. Materials The materials used in the comparative sample (CS) and the inventive examples (IE) of the present invention are provided in Table 1 below.

[0075]

Table 1

[0076] 3. Formulations

[0077]

Table 2

[0078] As shown in Table 2 above, the grafted BiTEMPS polymer was prepared by one of the two methods described herein, extrusion and Haake mixing. Xplore MC40 microextrusion Particularly for IE5, ENGAGE™ 8450, dicumyl peroxide, and BiTEMPS methacrylate were combined in the amounts shown in Table 2 and batch mixed at 100 °C in a Haake mixer to form a crosslinkable / pre-grafted polymer composition. Prior to extrusion, the formulation was evaluated by RPA at 160 °C for 60 minutes to understand the reactivity characteristics of the composition. It is notable that at this temperature (160 °C), DCP is induced to form radicals that initiate both the graft reaction and the crosslink reaction between BiTEMPS and ENGAGE™ 8450. Since the decomposition temperature of DCP has been reported to be 133 - 143 °C, these reactions are known to typically occur at temperatures above 140 °C. Jiayu Lv, et al., “Kinetic analysis and self-accelerating decomposition temperature (SADT) of dicumyl peroxide,” Thermochimica Acta, Volume 571, 2013, Pages 60 - 63. Also, it is known that the reactivity increases with increasing temperature.

[0079] Figure 1 provides the RPA profile (torque vs. viscosity) at 160 °C for 1 hour for IE5. As seen in Figure 1, the torque and viscosity increased when the compound temperature was maintained at 160 °C, thereby confirming that the graft reaction was effectively initiated at temperatures above 160 °C.

[0080] Next, the sample obtained from the batch mixing was further reactive extruded on an Xplore MC40 microcompounder ("MC40"), and coiled strands were collected. For this process, a 20 g batch mixing sample was processed on the MC40. At a temperature of 200 °C, first, the screw speed was set to 25 rpm. Approximately 10 g of the sample was added to the MC40 and melted for about 30 of 3 minutes. Then, an additional 10 g of the sample was added. The screw speed was increased to 50 rpm. Then, the material was recycled in the microcompounder for 5 minutes, at which point a stable torque reading was achieved. Then, a single extrudate strand with a diameter of approximately 4 mm was extruded from the microcompounder. The properties of the extruded material are reported in Table 3 below.

[0081]

Table 3

[0082] The viscosity temperature reprocessing ratio is defined as the ratio of n* at 0.1 rad / s and 160 °C to n* at 0.1 rad / s and 230 °C. S' at 160 °C for 60 minutes and n* at 0.1 rad / s and 160 °C indicate that IE5 has undergone a crosslinking reaction. A significant decrease in n* at 0.1 rad / s and 230 °C (high viscosity temperature reprocessing ratio) indicates that the crosslinked composition can be reprocessed at this high temperature.

[0083] The extruded strand was collected on a Teflon® sheet held approximately 6 inches from the die exit and manually moved to collect the coiled strand, where the extrudate formed a coil on its own to form a junction point, reproducing the 3D loop extrusion and joining process. The coiled strand was cooled to room temperature. The strength of the strand junction was evaluated by cutting individual joined junction points from the coiled strand and evaluating them under uniaxial tension on an Instron test frame. The peak load was measured for IE5 and reported in Table 4 below.

[0084]

Table 4

[0085] IE5 has a measurable peel strength, indicating that adhesion occurred between the extruded strands and that articles similar to 3D loop materials, and thus 3D loop structures, can be formed using the reversibly crosslinked composition IE5 composition.

[0086] Haake (trademark) batch mixing Examples 6 - 7 were prepared using a Haake (trademark) mixer in the following manner. This process mimics a reactive extrusion process where the reactive components (i.e., DCP and BiTEMPS) are added to the polymer melt at a temperature at which DCP can kick off the grafting / crosslinking reaction, followed by further mixing in a mixing or extrusion device. Haake (trademark) mixing studies are commonly used to determine candidates for reactive extrusion when the amounts required for reactive extrusion are not available.

[0087] The polymer formulations of IE6 - 7 are listed in Table 2. For each composition in Table 2, the polymer pellets were melt blended in an RSI RS5000 with a CAM blade, RHEOMIX 600 (available as a Haake (trademark) mixer from Polylabs (trademark)) batch mixer at 180 °C for a total of 15 minutes. This completely melted the HDPE polymer. After this 15 - minute period, DCP and BiTEMPS were added over 10 minutes at 180 °C.

[0088] As shown in Figures 2 and 3, it is clearly shown that grafting / crosslinking occurred during the mixing process. After adding BiTEMPS and DCP at 180 °C (approximately 600 seconds or 10 minutes), a significant increase in mixing torque was observed.

[0089] The reactive grafted polymer sample was then mixed for an additional 5 minutes and then removed from the RSI RS5000, RHEOMIX 600 (available as a Haake (trademark) mixer from Polylabs (trademark)) batch mixer.

[0090] At temperatures exceeding 230 °C, it was discovered that side reaction substances were generated, the polymer changed to a dark brown color, and the physical properties of the polymer were deteriorated. However, when the batch mixing temperature was less than 150 °C, grafting did not occur, and when the polymer blend was high, torque.

[0091] After removing from the batch mixer IE6 - 7, compression - molded specimens were formed at 180 °C and a molding pressure of 10 MPa for 5 minutes, and then rapidly cooled for 2 minutes between cooling platens (15 °C - 20 °C). The properties of IE6 and 7 are provided in Table 4 below.

[0092]

Table 5

[0093] 4. Preparation of Reprocessed Thermoplastic Articles (Process C) After compression - molding and cooling, IE7 from Table 4 was reprocessed under conditions such that the thermoset material was reprocessed into a thermoplastic material. Here, the IE7 compression - molded polymer plate was cut into strips and fed to a co - rotating twin - screw Xplore MC40 micro - compounder at 50 RPM and a temperature range of 230 °C for 6 minutes. Then, the polymer strands were extruded from the outlet of the micro - compounder and collected on the surface of a Teflon (trademark) - coated stainless - steel plate and cooled.

[0094] The viscosity (torque) decreased due to the dissociation bonds between the polymers, and the sample could be extruded successfully in a continuous manner. At temperatures higher than 250 °C, side reaction substances were generated and as a result, the sample was decomposed, but temperatures less than 200 °C resulted in high - torque strain - suppressed extrusion. Figure 4 shows a parallel comparison of compression - molded IE7 and reprocessed IE7’ (RPA profiles at 200 - 230 °C for the reprocessed Example IE7’).

[0095] Table 5 provides the extrusion conditions for the following reprocessed IE7.

[0096]

Table 6

[0097] As shown in FIG. 4, a thermosetting material for a thermoplastic material that can be further post-processed on an article or compounded for subsequent use. Non-limiting examples of suitable articles include elastic films, elastic fibers, soft-touch items such as toothbrush handles and appliance handles, gaskets and profiles, adhesives (including hot melt adhesives and pressure-sensitive adhesives), footwear (including shoe soles and shoe liners), automotive interior parts and profiles, foam 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.

[0098] 5. Preparation of the reprocessed thermosetting article (D) The reprocessability of IE5 under conditions for preparing a thermosetting material is also provided herein. The extruded strands were reprocessed to form compression molded packs for compression set testing. The strands of IE5 were cut into small pieces and compression molded into packs 1.2 inches in diameter and 0.5 inches thick at 180 °C for 15 minutes on a Carver molding machine with model 4095, 60-ton Dual daylight opening size 12’’×12’’, and temperature range capability of -20 °C to 260 °C. Third, the compression set at 70 °C was evaluated as reported in Table 6 comparing the reprocessed IE5’ to a compression mold of ENGAGE™ 8450. As seen below, IE5’ had a compression set similar to the uncrosslinked ENGAGE™ 8450 example, demonstrating that the reversibly crosslinked composition retains similar physical properties at 70 °C. Next, each compression set pack of ENGAGE™ 8450 and IE5’ was reprocessed by compression molding to form new packs 1.2 inches in diameter and 0.5 inches thick by compression molding at 180 °C for 15 minutes. Next, each sample was compressed at 125 °C for 22 hours at 25% strain and then cooled to room temperature. Figure ZZZ shows a photograph of a top view of each compression set pack after compression at 125 °C for 22 hours at 25% strain. ENGAGE™ 8450 melted and deformed at 125 °C, which is above the melting point of the sample and ENGAGE™ 8450 is not crosslinked. On the other hand, IE5’ retained all of its shape, demonstrating the improved heat resistance of the crosslinked sample as shown in Figure 5.

[0099] [Table 7]

[0100] The present disclosure is not limited to the embodiments and examples contained herein, and is particularly intended to include modified forms of those embodiments, including portions of the embodiments and combinations of elements of different embodiments, to the extent applicable to the following claims.

Claims

1. It is a process, (i) A (polar) ethylene-based polymer having a melting temperature Tm, (ii) Decomposition temperature T ｄｅｃｏｍｐ A free radical initiator having, To provide a crosslinkable polymer composition comprising (iii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate), In a mixing apparatus, the blend components are mixed at a temperature above the decomposition temperature of peroxides, A process comprising forming a BiTEMPS methyl acrylate grafted (polar) ethylene polymer (BiT-g-pPE).

2. The process according to claim 1, comprising forming a BiT-g-pPE containing a bond having structure 3. 【Chemistry 1】

3. The aforementioned mixing (A) Melt-blending the (polar) ethylene-based polymer at a first temperature over a first process period, (B) Adding the BiTEMPS methacrylate and free radical initiator to the molten-blended ethylene polymer of step (A) over a second process period to form a reaction mixture, The process according to claim 1, comprising (c) blending the reaction mixture over a third process period at a second temperature, and (d) forming the BiT-g-pPE.

4. The process according to claim 3, wherein the free radical initiator is dicumyl peroxide and the second temperature is 160°C to less than 180°C.

5. The process according to claim 1, comprising collecting the BiT-g-pPE as pellets, one or more bales, and combinations of pellets and one or more bales.

6. The BiT-g-pPE is heated to a crosslinking temperature of 180°C to less than 199°C, The process involves forming BiT-g-pPE into a preform at the aforementioned crosslinking temperature, Cooling the preform to below the crosslinking temperature, A process according to any one of claims 1 to 5, comprising forming a crosslinked article.

7. The aforementioned crosslinked article, (i) The (polar) ethylene polymer and, (ii) The process according to claim 6, comprising a bond having structure 2. 【Chemistry 2】

8. The aforementioned crosslinked article is crushed to form a crushed material, The pulverized material is heated to a reprocessing temperature of 180°C to 199°C, At the aforementioned reprocessing temperature, the refracted material is formed into a reprocessable (polar) ethylene-based polymer composition. The reprocessable (polar) ethylene-based polymer composition is molded into a reprocessed preform at the aforementioned reprocessing temperature. The reprocessed preform is cooled to a temperature below the reprocessing temperature, The process according to claim 6, comprising forming a reprocessed crosslinked article.

9. The crosslinked article is heated to a reprocessing temperature of 200°C to less than 250°C, At the aforementioned reprocessing temperature, the crosslinked article is formed into a reprocessable (polar) ethylene-based polymer composition. At the aforementioned reprocessing temperature, the reprocessable ethylene-based polymer composition is molded into a reprocessed preform. The reprocessed preform is cooled to a temperature below the reprocessing temperature, The process according to claim 6, comprising forming a reprocessed thermoplastic article.

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