Reversible Crosslinked 3D Loop Articles and Processes

Abstract

The present disclosure provides an article. In one embodiment, the article is a three-dimensional random loop material (“3DRLM”) composed of a web structure of a plurality of wound continuous strands melt-joined together at a plurality of contact points to form a plurality of loops. Each continuous strand is composed of a crosslinked composition formed from starting materials including (i) an ethylene-based polymer and (ii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate). Thereby, a 3DRLM composed of a crosslinked composition including (i) an ethylene-based polymer and (ii) a bond having the structure (2) of the following (I) is obtained 【Chemical 1】 JPEG2025524609000014.jpg30170

Description

Technical Field

[0001] Three-dimensional loop ("3DL") cushions made of thermoplastic resin have been developed for applications such as automotive seats and consumer mattresses. The 3DL cushions made of thermoplastic resin are viable alternatives to thermoset polyurethane foams. Since the 3DL cushions are made of thermoplastic resin, these 3DL structures can be recycled by melt processing. Polyolefins having a density in the range of 0.860 g / cc to 0.925 g / cc and a melt index (MI) in the viscosity range of 0.5 g / 10 min to 30 g / 10 min have been demonstrated to be useful in the manufacture of 3D loop cushions with good balance of properties.

[0002] In certain 3DL cushion applications, particularly 3DL cushion transportation applications (including automobiles, trains, and buses), high heat resistance (compression set at high temperature) is required for the cushion articles. The current heat resistance of polyolefin solutions is not sufficient for certain transportation applications. Crosslinking can be used to improve the heat resistance of these articles, but conventional crosslinked 3DL cushion materials cannot be recycled by melt processing. Therefore, the art recognizes the need for 3DL cushion materials that (i) have high heat resistance and (ii) are recyclable by melt processing.

Summary of the Invention

[0003] The present disclosure provides an article. In one embodiment, the article is a three-dimensional random loop material (3DRLM) composed of a web structure of a plurality of wound continuous strands melt-joined together at a plurality of junctions to form a plurality of loops. Each continuous strand is composed of a crosslinked composition formed from starting materials including (i) an ethylene-based polymer and (ii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate). Thereby, a 3DRLM composed of a crosslinked composition including (i) an ethylene-based polymer 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 first article, the first article being composed of a three-dimensional random loop material including a web structure of a plurality of wound continuous strands melt-joined together at a plurality of junctions to form a plurality of loops, and each continuous strand being composed of a crosslinked composition including (i) an ethylene-based polymer and (ii) a bond having structure (2), to a reprocessing temperature

[0006]

Chemical formula

[0007] The coating is formed from starting materials of an ethylene polymer and 2,2,6,6 - tetramethyl - 4 - piperidyl methacrylate disulfide (BiTEMPS) methacrylate. The process includes heating the coating to a reprocessing temperature and forming the coating into a reprocessable ethylene polymer composition at the reprocessing temperature. The process includes shaping the reprocessable ethylene polymer composition into a reprocessed preform at the reprocessing temperature. The process includes cooling the reprocessed preform to below the reprocessing temperature to form a second article composed of (i) an ethylene polymer and (ii) a crosslinked ethylene polymer composition composed of bonds having structure (2).

Brief Description of the Drawings

[0008]

Figure 1

Figure 1A

Figure 2-1

Figure 2-2

[0009] 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 implicit 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 referenced in this specification are hereby incorporated by reference in their entirety (or, where an equivalent U.S. version is available, such equivalent U.S. version is hereby incorporated by reference in like manner).

[0010] 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 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, in the above range of 1 to 7, sub-ranges such as 1 to 2, 2 to 6, 5 to 7, 3 to 7, 5 to 6, etc. are included).

[0011] Unless otherwise stated, unless implicit 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.

[0012] As used herein, the term "composition" refers to a mixture of materials that comprises the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0013] 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 doubt, all compositions claimed through the use of the term "comprising" may, unless inconsistent with the description, 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 component, step, or procedure not specifically depicted or listed.

[0014] "Ethylene polymer" is a polymer that contains more than 50 mol% of polymerized ethylene monomer (based on the total amount of polymerizable monomers) and may optionally 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), 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, homogeneous catalyst systems containing ligand structures such as non-metallocene metal centers, heteroaryls, heterovalent aryloxyethers, phosphinimines, etc., and others, in gas phase, fluidized bed reactor, liquid phase slurry process reactor, or liquid phase solution process reactor. Combinations of heterogeneous catalysts and / or homogeneous catalysts can also be used in either a single reactor or a multi-reactor configuration.

[0015] "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 interpolymer containing a homogeneous short-chain branch distribution including units derived from an α-olefin comonomer. The ethylene plastomer / elastomer has a density of 0.854 g / cc to 0.917 g / cc. Non-limiting examples of the ethylene plastomer / elastomer include AFFINITY™ polyolefin plastomers and ENGAGE™ polyolefin elastomers (available from The Dow Chemical Company), EXACT™ plastomers (available from ExxonMobil Chemical), Tafmer™ alpha olefin copolymers (available from Mitsui), Solumer™ polyolefin elastomers and Supreme™ polyolefin elastomers (available from SK Chemicals Co.), and Lucene™ polyolefin elastomers (available from LG Chem Ltd.).

[0016] "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 a 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 from 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 to 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 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 (commercially available from The Dow Chemical Company), ELITE™ enhanced polyethylene resin (commercially available from The Dow Chemical Company), CONTINUUM™ bimodal polyethylene resin (commercially available from The Dow Chemical Company), LUPOLEN™ (commercially available from LyondellBasell), and HDPE products from Borealis, Ineos, and ExxonMobil.

[0017] "Linear low density polyethylene" (or "LLDPE") is a linear ethylene / α-olefin copolymer containing units derived from ethylene and units derived from at least one C3-C 10 α-olefin, or a C4-C8 α-olefin comonomer, and having a homogeneous or 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 ELITE™ enhanced polyethylene resin, 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).

[0018] "Low density polyethylene" (or "LDPE") is an ethylene homopolymer or contains at least one C3-C having a density of 0.915 g / cc to 0.940 g / cc and having a broad molecular weight distribution and long chain branching. 10It consists of an ethylene / α-olefin copolymer containing α-olefin or C4-C8 α-olefin. LDPE is typically produced by high-pressure free radical polymerization (tubular reactor or autoclave using a free radical initiator). Non-limiting examples of LDPE include AGILITY (trademark) Performance LDPE and DOW (trademark) LDPE (available from The Dow Chemical Company), MarFlex (trademark) (Chevron Phillips), LUPOLEN (trademark) (LyondellBasell), and LDPE products from Borealis, Ineos, ExxonMobil, and others.

[0019] As used herein, "olefinic polymer" or "polyolefin" is a polymer that contains a polymerized olefin monomer greater than 50 mole percent (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.

[0020] "Polymer" is a compound prepared by polymerizing monomers, whether of the same or different types, which provides a plurality of and / or repeating "units" or "structural units" constituting the polymer in a polymerized form. 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 includes 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-mentioned copolymers prepared by polymerizing ethylene or propylene and one or more additional polymerizable α-olefin monomers, respectively. 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, it should be noted that the term "monomer" is understood to refer to the polymerized residue of the specified monomer and does not refer to non-polymerized species. Generally, polymers herein are referred to as being based on "units" that are the polymerized form of the corresponding monomers.

[0021] Test Methods Apparent density. The sample material was cut into square pieces with a size of 38 cm × 38 cm (15 inches × 15 inches). The volume of this small piece was calculated from the thickness measured at four points. The apparent density was obtained by dividing the weight by the volume (taking the average of four measurements), and the value was reported in grams per cubic centimeter, g / cc.

[0022] Compression set. Compression set was measured according to ASTM D395, Method B, at 70 °C for 22 hours (hr) with a 25% strain, using one test piece per sample.

[0023] Density was measured using isopropanol according to ASTM D792, Method B, and the results were reported at 25 °C in g / cc.

[0024] Rheological analysis using a Rubber Process Analyzer (RPA). The rheology of the composition was measured using an Alpha Technologies RPA 2000 instrument, a rotorless oscillatory shear rheometer, in accordance with ASTM D6204, based on the following test conditions and exceptions. The sample was placed between two Mylar films for analysis. Rheology was monitored during an initial timed test at 160 °C, 1.0 rad / s, 7% strain for 60 minutes. The elastic torque S’ at the end of the 60-minute 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 160 °C, 7% strain, followed by a frequency sweep from 0.1 to 300 rad / s at 190 °C, 7% strain, and then a frequency sweep from 0.1 to 300 rad / s at 230 °C, 7% strain. The dynamic complex viscosity η * , and tan delta were recorded for each frequency sweep. In ASTM D6204, the frequency sweep for unvulcanized rubber is performed before the curing process. In this case, the frequency sweep was performed after the first crosslinking step at 160 °C to evaluate the reversibility of crosslinking.

[0025] (The) melt index (MI or I2) (of the ethylene polymer) was measured in accordance with ASTM D 1238 under the conditions of 190 °C / 2.16 kg, and the results are reported in grams per 10 minutes (g / 10 min).

[0026] Strand peel strength. Samples were prepared by extruding strands on an Xplore MC40 microcompounder ("MC40") and collecting the coiled strands. 20 g of sample was processed on the MC40. The temperature was set at 200 °C for all experiments. First, the screw speed was set at 25 rpm. Approximately 10 g of sample was added to the MC40 and melted for about 30 seconds. Then, an additional 10 g of sample was added. The screw speed was increased to 50 rpm. The material was then recycled in the microcompounder for 5 minutes, at which point a stable torque reading was achieved. A single extruded strand with a diameter of approximately 4 mm was then extruded from the microcompounder. 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 coiled onto itself to form a junction point, replicating the 3D loop extrusion and bonding process. The coiled strand was cooled to room temperature. The strength of the strand junction was evaluated by cutting individual bonded junction points from the coiled strand and evaluating under uniaxial tension on an Instron test frame. Samples were tested at a crosshead displacement rate of 5 inches / minute at room temperature. The peak load at which the strand broke or was peeled at the junction point was recorded. The average peak load of 3 - 5 specimens was reported for each sample.

DETAILED DESCRIPTION OF THE INVENTION

[0027] The present disclosure is an article. The article is composed of a three-dimensional random loop material (or "3DRLM"). The 3DRLM includes a web structure of a plurality of wound continuous strands melt-bonded together at a plurality of contact points to form a plurality of loops. Each continuous strand is composed of a crosslinked polymer composition formed from a starting material comprising (i) an ethylene-based polymer and (ii) 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate).

[0028] A. 3DRLM The present disclosure is directed to articles composed of three-dimensional random loop material (or "3DRLM"). For illustrative purposes, FIG. 1 shows a slab 10 composed of three-dimensional random loop material 30. It is understood that the 3DRLM may embody countless different shapes and is not limited to slabs. The slab 10 has a geometric shape. As used herein, a "geometric shape" is a three-dimensional shape or three-dimensional configuration having length, width, and height. The geometric shape may be a regular three-dimensional shape, an irregular three-dimensional shape, or a combination thereof. Non-limiting examples of regular three-dimensional shapes include cubes, prisms, spheres, cones, and cylinders. The slab may be solid or hollow. When the geometric shape of the slab is a prism, it is understood that the prism may have a cross-sectional shape that is a regular polygon or an irregular polygon having 3, 4, 5, 6, 7, 8, 9, 10, or more sides. Further, when the geometric shape of the slab is a cylinder, it is understood that the cylinder may have a cross-sectional shape that is an ellipse or a circle.

[0029] The slab 10 is composed of a three-dimensional random loop material 30. As shown in FIG. 1A, a "three-dimensional random loop material" (or "3DRLM") is a mass or structure of a number of loops 32 formed by winding a continuous strand 34 and bringing each loop into contact with each other in a molten state and thermally joining or otherwise fusion-joining them at the joints 36. Even when a large stress that causes significant deformation is applied, the 3DRLM 30 absorbs the stress throughout the network structure composed of the melt-integrated three-dimensional random loops by deforming itself, and when the stress is released, the elastic elasticity of the polymer appears, enabling the structure to recover to its original shape. When a mesh structure composed of continuous strands made of a known inelastic polymer is used as a cushioning material, plastic deformation occurs and recovery cannot be achieved, resulting in inferior durability. If the strands are not fusion-joined at the joints, a fatigue phenomenon occurs due to stress concentration, and as a result, the shape cannot be maintained, the structure does not deform integrally in its shape, and thus the durability and deformation resistance decrease. In certain embodiments, the fusion joining is such that all the joints are fusion-joined.

[0030] A non-limiting method for manufacturing 3DRLM30 includes: (a) heating a molten olefin-based polymer (ethylene-based polymer, BiTEMPS methacrylate, free radical initiator) at a temperature 10 °C to 140 °C higher than the melting point and / or glass transition temperature of the polymer in a typical melt extruder; (b) discharging the molten interpolymer downward from a die having a plurality of orifices to form a continuous strand that naturally (by gravity) falls; and contacting the extruded strand in a fluid (e.g., a water bath) below the crystallization temperature of the polymer to allow the strand to form loops while solidifying. The polymer can be used in combination with a thermoplastic elastomer, a thermoplastic non-elastomeric polymer, or a combination thereof. The distance between the die surface and the take-up conveyor installed on the cooling unit to solidify the strand, the melt viscosity of the polymer, the diameter of the orifice, and the discharge rate are factors that determine the loop diameter and the strand diameter. The loops hold and position the supplied molten strands between a pair of take-up conveyors (belts or rollers) set on the cooling unit (the adjustable distance therebetween) so that the contacting loops are thermally joined, or otherwise melt-joined, when they form a three-dimensional random loop structure. The loops are formed by bringing the loops formed in this way into contact with each other by adjusting the distance between the orifices for this purpose. Then, the continuous strand with thermally joined joints when the loops form a three-dimensional random loop structure is continuously taken into the cooling unit and solidified into a mesh structure. Thereafter, the structure is cut to the desired length and shape. The method is characterized by melt-heating an olefin-based polymer at a temperature 10 °C to 140 °C higher than the melting point of the interpolymer and supplying it downward in a molten state from a die having a plurality of orifices. When the polymer is discharged at a temperature less than 10 °C higher than the melting point, the supplied strand becomes cold and less fluid, and the thermal adhesion of the strand joints becomes insufficient.

[0031] The characteristics such as the loop diameter and the strand diameter that make up the buffer mesh structure provided in this specification depend on the distance between the die surface and the take-out conveyor installed on the cooling unit to solidify the interpolymer, the speed of the take-out conveyor, the melt viscosity of the interpolymer, the diameter of the orifice, and the amount of the interpolymer supplied therefrom. For example, when reducing the amount of the interpolymer supplied, lowering the melt viscosity, increasing the distance between the die and the conveyor, and increasing the conveyor speed during supply, the strand diameter becomes smaller and the average loop diameter of the random loops becomes smaller. On the other hand, when the distance between the die surface and the take-out conveyor installed on the cooling unit to solidify the interpolymer becomes shorter, the strand diameter becomes slightly larger and the average loop diameter of the random loops becomes larger. The orifice diameter also affects the strand diameter and the loop diameter. When the orifice diameter is small, the strand diameter becomes small and the loop diameter becomes small. When the orifice diameter is large, the strand diameter becomes large and the loop diameter becomes large. By combining these conditions, a desired diameter of the continuous strand of 0.1 mm to 4 mm and an average diameter of the random loops of 100 mm or less, or 1 millimeter (mm), or 2 mm, or 10 mm to 25 mm, or 50 mm can be obtained. By adjusting the distance to the aforementioned conveyor, the thickness of the structure can be controlled while the thermally bonded mesh structure is in a molten state, and a structure having a desired thickness and a flat surface formed by the conveyor can be obtained. If the conveyor speed is too fast, cooling proceeds before thermal bonding, so the joints cannot be thermally bonded. On the other hand, if the speed is too slow, a higher density may result from an overly long residence of the molten material. In some embodiments, the distance to the conveyor and the conveyor speed should be selected such that a desired apparent density of 0.005 to 0.1 g / cc or 0.01 to 0.05 g / cc can be achieved.

[0032] The 3DRLM 30 is formed in a three-dimensional geometric shape (i.e., a prism) to form a slab. The 3DRLM 30 is an elastic material that can be compressed and stretched and can return to its original geometric shape. As used herein, "elastic material" is a rubber-like material that can be compressed and / or stretched and rapidly expands and contracts approximately to its original shape / length when the force applied for compression and / or stretching is released. The three-dimensional random loop material 30 has a "neutral state" when no compressive force and tensile force are applied to the 3DRLM 30. The three-dimensional random loop material 30 has a "compressed state" when a compressive force is applied to the 3DRLM 30. The three-dimensional random loop material 30 has a "stretched state" when a tensile force is applied to the 3DRLM 30.

[0033] B. Ethylene-based polymer The 3DRLM is formed from a crosslinkable polymer composition (synonymously referred to as "starting material") containing an ethylene-based polymer. The ethylene-based polymer is an ethylene homopolymer, an ethylene / α-olefin interpolymer, or ethylene C4-C 20It can be an α-olefin copolymer. In the embodiments of the present specification, the ethylene-based polymer contains units derived from ethylene in an amount exceeding 50% by weight and units derived from one or more α-olefin comonomers in an amount less than 30% by weight (based on the total amount of polymerizable monomers). All individual values and subranges of units derived from ethylene in an amount exceeding 50% by weight and units derived from one or more α-olefin comonomers in an amount less than 30% by weight. 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 constitutes more than 0% by weight to less than 30% by weight of units derived from one or more of 1-octene, 1-hexene, or 1-butene comonomers.

[0034] 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 0.860 to 0.925 g / cc. All individual values and sub-ranges from 0.860 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.

[0035] 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.

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

[0037] 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. Non-limiting examples of suitable ethylene / C4 - C8 α-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.

[0038] In one embodiment, the ethylene-based elastomer is an ethylene / α-olefin multiblock copolymer. The term "ethylene / α-olefin multiblock copolymer" refers to an ethylene / C3 - C8 α-olefin multiblock copolymer consisting of polymerized forms of ethylene and one copolymerizable C3 - C8 α-olefin comonomer or C4 - C8 α-olefin comonomer (and optional additives), where the polymer is characterized by multiple blocks or segments of two polymerized monomer units having different chemical or physical properties, and the blocks are joined (or covalently bonded) linearly. That is, the polymer contains chemically distinct units with ends joined to the polymerized ethylenic functional groups. Ethylene / α-olefin multiblock copolymers include block copolymers having two blocks (diblock) and more than two blocks (multiblock). The C3 - C8 α-olefin is selected from propylene, butene, hexene, and octene. The ethylene / α-olefin multiblock copolymer does not contain, or alternatively excludes, styrene (i.e., styrene-free), and / or vinyl aromatic monomers, and / or conjugated dienes. 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 multiblock 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.

[0039] 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 constitutes at least 60% by weight, at least 70% by weight, or at least 80% by weight, together with substantially the remainder of the ethylene / α-olefin multiblock copolymer containing a C3 - C8 α-olefin comonomer or a C4 - C8 α-olefin comonomer. In one embodiment, the ethylene / α-olefin multiblock copolymer contains 50% - 90% by weight of ethylene, or 60% - 85% by weight of ethylene, or 65% - 80% by weight of ethylene.

[0040] 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 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 zero at a minimum. 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 100 wt%.

[0041] The soft segment may be present in the ethylene / α-olefin multi-block copolymer in an amount of 1 wt% to 99 wt% of the total weight of the ethylene / α-olefin multi-block 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 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. 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.

[0042] Furthermore, the ethylene / α-olefin multi-block copolymer has a PDI (or Mw / Mn) that conforms to a Schultz-Flory distribution rather than a 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.

[0043] In one embodiment, the ethylene / α-olefin multiblock copolymer has a most probable distribution of block lengths.

[0044] In one embodiment, the ethylene / α-olefin multiblock copolymer is an ethylene / 1-octene multiblock 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 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 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 ​ (ix) Polydispersity distribution of blocks and polydispersity distribution of block sizes (hereinafter referred to as characteristics (i) to (ix) of the multiblock copolymer).

[0045] 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).

[0046] 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 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.

[0047] C. Free radical initiator The crosslinkable polymer composition in which 3DRLM is formed 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-dimethylhexine-3,1,1-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.

[0048] In one embodiment, the free radical initiator is dicumyl peroxide.

[0049] D.BiTEMPS methacrylate The crosslinkable polymer composition in which 3DRLM is formed 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.

[0050]

Chem.

[0051] In one embodiment, the crosslinkable composition comprises 70 wt% to 98.5 wt%, or 77 wt% to 98.5 wt% of an ethylene polymer, 0.1 wt% to 10 wt%, or 0.1 wt% to 5 wt%, or 0.1 wt% to 3.0 wt%, or 0.1 wt% to 1.5 wt%, or 0.5 wt% to 1.5 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 2 wt% to 20 wt%, or 2 wt% to 10 wt% of BiTEMPS methacrylate disulfide. It is understood that the aggregate of the ethylene polymer, the free radical initiator, and BiTEMPS methacrylate disulfide (and optional additives) amounts to 100 wt% of the crosslinkable polymer composition.

[0052] The crosslinked composition of continuous strands for 3DRLM is formed from the crosslinkable polymer composition. The crosslinkable polymer composition is melt blended at a temperature of 100 °C to 250 °C, or 120 °C to 210 °C, or 140 °C to 210 °C, or 140 °C to 190 °C to cause a crosslinking reaction and form the crosslinked composition. In one embodiment, the crosslinked composition comprises an ethylene polymer and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate). The crosslinked composition contains disulfide bonds formed from BiTEMPS methacrylate by the crosslinking reaction, and the disulfide bonds have the following Structure 2.

[0053]

Chem.

[0054] The term "P" (and structure) in the above structure 2 refers to the chain of polymerized ethylene (and optional comonomer) of the 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. 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.

[0055] In one embodiment, the ethylene-based polymer is an unused ethylene-based polymer. As used herein, "unused ethylene-based polymer" is an ethylene-based polymer that has not been subjected to a crosslinking reaction. In other words, the term "unused ethylene-based polymer" refers to the ethylene-based polymer present in the crosslinked composition before the ethylene-based polymer is crosslinked with BiTEMPS methacrylate. The unused ethylene-based polymer is the ethylene-based polymer before crosslinking, and the crosslinked composition contains the same ethylene-based polymer that was unused but is now crosslinked with BiTEMPS methacrylate. In this way, the unused 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, and is formed by 3DRLM as disclosed above.

[0056] In one embodiment, the crosslinked composition comprises (i) an ethylene-based polymer in an amount of 80 wt% to 99.9 wt%, or 80 wt% to 98 wt%, and (ii) a bond of structure (2) formed from 2 wt% to 20 wt% of BiTEMPS methacrylate, and the aggregate of the ethylene-based polymer and the bond of structure (2) (and optional additives) is 100 wt% of the crosslinked composition. The crosslinked composition in the strand of 3DRLM has (i) a storage modulus value G' at 60 °C greater than 1 MPa, and (ii) a storage modulus value G' at 140 °C greater than 0.1 MPa, and (iii) a tan delta value at 60 °C less than 0.17, and (iv) a tan delta value at 140 °C less than 0.62.

[0057] E. 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 ethylene vinyl acetate (EVA), polyolefins (e.g., polyethylene other than ethylene-based polymers crosslinked with BiTEMPS methacrylate and polypropylene), additional "unused ethylene-based polymers (e.g., the same ethylene-based polymer used in the crosslinked composition but not reacted or crosslinked with BiTEMPS methacrylate), 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, e.g., polyvinyl chloride, polystyrene, polyurethane, etc., and mixtures thereof.

[0058] In one embodiment, the polyolefin is a homopolymer such as polyethylene, polypropylene, polybutylene, poly(1-pentene), poly(3-methyl-1-butene), poly(4-methyl-1-pentene), polyisoprene, polybutadiene, poly(1,5-hexadiene), poly(1-hexene), poly(1-octene), and poly(1-decene).

[0059] Non-limiting examples of polyethylene (other than ethylene polymers crosslinked with BITEMPS methacrylate) suitable 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. For example, LDPE or LLDPE commercially available under the trade names DOWLEX™, DNDA, and ATTANE™, all of which are available from The Dow Chemical Company (Midland, Mich.).

[0060] F. 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.), auxiliaries (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.

[0061] G. Process BiTEMPS methacrylate is a "dynamic crosslinking agent". The dynamic crosslinking agent BiTEMPS methacrylate enables the formation of a crosslinked network of the ethylene-based polymer by disulfide bonds between the chains of the ethylene-based polymer. The crosslinked network is formed by the ethylene-based polymer and BiTEMPS methacrylate in the presence of a free radical initiator for forming a crosslinked ethylene-based polymer composition. When the crosslinked ethylene-based polymer composition is subjected to a "reprocessing temperature" which 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.

[0062] 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 enables bond breakage and polymer chain flow, allowing 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 enabling the molding and / or secondary processing of the fluid reprocessable ethylene-based composition (including BiTEMPS methacrylate) 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 with the high viscosity (not 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 newly 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 a crosslinked network and resistance to mechanical deformation. This cycle of crosslinking / reprocessing / recrosslinking into a new article can be repeated.

[0063] 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 crosslinked ethylene-based polymer compositions that are 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.

[0064] 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.

[0065] The present disclosure provides a process. In one embodiment, the process includes heating a first article to a reprocessing temperature. The first article is composed of a three-dimensional random loop material that is a web structure of a plurality of wound continuous strands that are melt joined together at a plurality of junctions to form a plurality of loops. Each continuous strand is composed of a crosslinked composition that includes an ethylene-based polymer and a bond of Structure 2 (and optional additives) formed from (2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS) methacrylate). The process includes forming the first article into a reprocessable ethylene-based polymer composition at the reprocessing temperature. The process includes shaping the reprocessable ethylene-based composition into a reprocessed preform at the reprocessing temperature. The process includes cooling the reprocessed preform to below the reprocessing temperature to form a second article composed of (i) an ethylene-based polymer and (ii) a re-crosslinked ethylene-based polymer composition composed of Structure 2 formed from (BiTEMPS methacrylate).

[0066] The second article may be the same as or different from the first article.

[0067] In one embodiment, the forming process is a procedure selected from the group consisting of injection molding, extrusion, extrusion molding, thermoforming, slush molding, overmolding, insert molding, blow molding, cast molding, tentering, compression molding, and combinations thereof.

[0068] Non-limiting examples of a second article suitable for the present recycled (reprocessed) ethylene-based polymer (including BiTEMPS methacrylate) composition include 3DL articles, 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 extruded 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, liners, cap liners, floor coverings, and combinations thereof.

[0069] The applicant has discovered a 3DRLM that can undergo reversible crosslinking at the reprocessing temperature. This is achieved by forming the 3DRLM from a crosslinkable polymer composition of an ethylene-based polymer, a peroxide, and BiTEMPS methacrylate (and optional additives). The composition of the present invention forms a 3DRLM that includes strands composed of the crosslinked composition, and the crosslinked composition is crosslinked at the application use temperature but can be melt reprocessed at a typical 3DRLM processing temperature (about 160 - 230 °C). As a result, the proposed solution is expected to provide the advantages of heat resistance and durability of the 3DRLM loop cushion while maintaining the (re)processability at typical extrusion temperatures.

[0070] By way of example and not limitation, some embodiments of the present disclosure will now be described in detail in the following examples.

[0071] 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.

[0072] [Table 1]

[0073] 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 at room temperature overnight 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.

[0074] [Chemical formula]

[0075] 3. Formulation Composition ENGAGE 8450, dicumyl peroxide, and BiTEMPS methacrylate were combined (in the amounts shown in Table 2 below) and batch mixed at 100 °C to form a crosslinkable polymer composition, Formulation A. Formulation A was heated on an RPA at 160 °C for 60 minutes to initiate the crosslinking reaction. The properties of the crosslinked composition are provided in Table 2 below.

[0076]

Table 2

[0077] The viscosity temperature reprocessing ratio is defined as the ratio of n at 0.1 rad / s and 230 °C to n at 0.1 rad / s and 160 °C. S’ at 160 °C and 60 minutes and n at 0.1 rad / s and 160 °C indicate that formulation A has undergone a crosslinking reaction. The 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. Formulation 1 is a thermoplastic without crosslinking and is thus essentially reprocessable. * to n at 0.1 rad / s and 160 °C * is defined. S’ at 160 °C and 60 minutes and n at 0.1 rad / s and 160 °C indicate that formulation A has undergone a crosslinking reaction. The 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. Formulation 1 is a thermoplastic without crosslinking and is thus essentially reprocessable. * indicate that formulation A has undergone a crosslinking reaction. The 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. Formulation 1 is a thermoplastic without crosslinking and is thus essentially reprocessable. * (high viscosity temperature reprocessing ratio) indicates that the crosslinked composition can be reprocessed at this high temperature. Formulation 1 is a thermoplastic without crosslinking and is thus essentially reprocessable.

[0078] Samples were prepared by extruding strands on an Xplore MC40 microcompounder (“MC40”) and collecting the coiled strands. 20 g of sample was processed on the MC40. The temperature was set at 200 °C for all experiments. First, the screw speed was set at 25 rpm. Approximately 10 g of sample was added to the MC40 and melted for about 30 seconds. Then, an additional 10 g of sample was added. The screw speed was increased to 50 rpm. Then, the material was recirculated in the microcompounder for 5 minutes, at which point a stable torque reading was achieved as recorded in Table 3 below. Then, a single extruded strand with a diameter of approximately 4 mm was extruded from the microcompounder. 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 coiled onto itself to form a junction point, reproducing the 3D loop extrusion and bonding process. The coiled strand was cooled to room temperature.

[0079]

Table 3

[0080] The strength of the strand joints was evaluated by cutting individual bonded junction points from the coiled strands and evaluating them under uniaxial tension on an Instron test frame. As reported in Table 3 (above), the peak load was measured for 3 - 5 specimens per sample. In the comparative sample (CS1) made from a conventional thermoplastic ethylene / octene copolymer (ENGAGE 8450), most of the strands broke before delamination occurred at the joints.

[0081] In the examples of the present invention composed of the reversibly crosslinked compositions (IE - B, IE - C, IE - D), the strands delaminated at the joints at the reported strand delamination peak load (Table 3 above). The peak loads for delamination of IE - B, IE - C, and IE - D were lower than those of the comparative sample CS - 1, but each example of the present invention of IE - B, IE - C, and IE - D had a measurable delamination force, indicating that adhesion occurred between the extruded strands and that an article similar to 3DRLM could be formed from the reversibly crosslinked composition.

[0082] For IE - D, it was demonstrated that a sample could be formed using the crosslinkable polymer composition formulation A and that the crosslinkable polymer composition could be easily processed into a final article, an extruded article comparable to a 3DRLM article having established reversible crosslinks. The examples IE - B to IE - D of the present invention were made using the example IE - A of the present invention. Formulation A was crosslinked by compression molding into plaques (10 cm × 10 cm × 2 mm) at 180 °C for 15 minutes to form IE - A. Then, IE - A was cut into small pieces for extrusion experiments on an Xplore MC40 microcompounder. Examples IE - B and IE - C demonstrated that the crosslinked material IE - A could be melt (re)processed into a new article (comparable to a 3DRLM article) due to the reversible nature of crosslinking at the processing temperature. Thus, each example IE - B, IE - C, and IE - D of the present invention demonstrates that a 3DRLM composed of an ethylene / octene copolymer crosslinked with BiTEMPS methacrylate can be melt processed and / or melt reprocessed.

[0083] Furthermore, to demonstrate the improved heat resistance of the crosslinked IE-B, IE-C, and IE-D examples, the extruded strands were reprocessed to form compression molded packs for compression set testing. The strands 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. First, the compression set at 70 °C was evaluated as reported in Table 4. IE-B, IE-C, and IE-D had a compression set similar to the uncrosslinked CS-1 example, demonstrating that the reversibly crosslinked compositions retain similar physical properties at 70 °C. Next, each compression set pack of CS-1, IE-B, IE-C, and IE-D was reprocessed by compression molding and compression molded at 180 °C for 15 minutes to form new packs 1.2 inches in diameter and 0.5 inches thick. Additionally, the compression molded plaques of IE-A were also compression molded into compression set packs. Next, each sample was compressed at 125 °C for 22 hours at 25% strain and then cooled to room temperature. Figure 2 shows a photograph of a top view of each compression set pack after compression at 125 °C for 22 hours at 25% strain. CS-1, which melted and deformed at 125 °C, was above the melting point of the sample and was not crosslinked. On the other hand, IE-A, IE-B, IE-C, and IE-D all retained their shape, demonstrating the improved heat resistance of these crosslinked samples.

[0084]

Table 4

[0085] The present disclosure is not limited to the embodiments and examples contained herein, and is particularly intended to include, to the extent applicable to the following claims, modified forms of those embodiments including parts of the embodiments and combinations of elements of different embodiments.

Claims

1. An article comprising a three-dimensional random loop material comprising a web structure of a plurality of wound continuous strands fusion bonded together at a plurality of junctions to form a plurality of loops, each continuous strand being composed of a crosslinked composition formed from starting materials comprising an ethylene polymer and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate).

2. The article according to claim 1, wherein the crosslinked composition comprises a structure 2 bond 【Chemical 1】

3. The crosslinked composition is formed from starting materials comprising 80 wt% to 99 wt% of an ethylene polymer having a melt index of 0.1 g / 10 min to 100 g / 10 min and 20 wt% to 1 wt% of the BiTEMPS methacrylate, the article according to claim 1 or 2.

4. The article according to any one of claims 1 to 3, wherein the ethylene polymer is an ethylene / α-olefin interpolymer having a density of 0.860 g / cc to 0.925 g / cc.

5. The article according to any one of claims 1 to 4, wherein the ethylene polymer is an ethylene / octene copolymer.

6. The ethylene polymer is the unused ethylene polymer before the crosslinked composition is crosslinked, and the crosslinked composition has (i) a storage modulus value G' at 140 °C greater than the storage modulus value G' of the unused ethylene polymer at 140 °C, (ii) a tan delta value at 60 °C less than the tan delta value of the unused ethylene polymer at 60 °C, and (iii) a tan delta value at 140 °C less than the tan delta value of the unused ethylene polymer at 140 °C, the article according to any one of claims 1 to 5.

7. An article comprising a three-dimensional random loop material comprising a web structure of a plurality of wound continuous strands fusion bonded together at a plurality of junctions to form a plurality of loops, each continuous strand being composed of a crosslinked composition comprising an ethylene polymer and a bond having structure 2. 【Chemical 2】

8. A process comprising a first article, the first article being composed of a three-dimensional random loop material comprising a web structure of a plurality of wound continuous strands fusion bonded together at a plurality of junctions to form a plurality of loops, each continuous strand being (i) an ethylene polymer; and heating a first article, composed of a crosslinked composition containing (ii) a bond having structure (2), to a reprocessing temperature; 【Chemical Formula 3】 forming the first article at the reprocessing temperature into a reprocessable ethylene polymer composition; shaping the reprocessable ethylene composition at the reprocessing temperature into a reprocessed preform; cooling the reprocessed preform to below the reprocessing temperature to form a second article composed of a re-crosslinked ethylene polymer composition composed of (i) the ethylene polymer and (ii) a bond having structure (2).

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