WO2019083881A1 - Three-dimensional loop material of bicomponent fiber - Google Patents

Abstract

The present disclosure is directed to a sheet. The sheet is composed of a three- dimensional random loop material comprising a web structure of a multitude of winding continuous fibers melt-bonded together at a multitude of contact points to form a multitude of loops. Each continuous fiber includes a component (1) that is an olefin-based polymer having a density from 0.86 g/cc to 0.96 g/cc, and a component (2) that is an olefin- based polymer having a density from 0.86 g/cc to 0.96 g/cc. The three-dimensional random loop material has an apparent density from 0.03 g/cc to 0.08 g/cc.

Description

THREE-DIMENSIONAL LOOP MATERIAL OF BICOMPONENT FIBER

BACKGROUND

[0001] Known are articles such as abrasive pads ("scrub pads") and floor matting made from a plurality of random loops arranged in a three-dimensional orientation ("3D"), the random loops formed from polyester elastomer. The random loops are polymeric filaments bonded to each other in an open non-woven web. The filaments of scrub pads can be made from a bicomponent polymeric material, typically a polyester elastomer, that is tough and durable for applying an abrasive force to a surface.

[0002] Polyester-based 3D loop material is tough and abrasive, lacking resilience and softness. Consequently, the art recognizes a need for 3D loop material made from materials other than polyester-based elastomers. A need further exists for random loop material made from multi-component polymeric materials that has suitable softness, resilience, compression/elasticity, and haptics for cushioning applications and/or packaging applications.

SUMMARY

[0003] The present disclosure is directed to a sheet. The sheet is composed of a three- dimensional random loop material comprising a web structure of a multitude of winding continuous fibers melt-bonded together at a multitude of contact points to form a multitude of loops. Each continuous fiber includes a component (1) that is an olefin-based polymer having a density from 0.86 g/cc to 0.96 g/cc, and a component (2) that is an olefin- based polymer having a density from 0.86 g/cc to 0.96 g/cc. The three-dimensional random loop material has an apparent density from 0.03 g/cc to 0.08 g/cc.

DEFINITIONS

[0004] All references to the Periodic Table of the Elements herein shall refer to the Periodic Table of the Elements, published and copyrighted by CRC Press, Inc., 2003. Also, any references to a Group or Groups shall be to the Groups or Groups reflected in this Periodic Table of the Elements using the lUPAC system for numbering groups. Unless stated to the contrary, implicit from the context, or customary in the art, all components and percents are based on weight. For 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 the equivalent US version thereof is so incorporated by reference).

[0005] The numerical ranges disclosed herein include all values from, and including, the lower value and the upper value. For ranges containing explicit values (e.g., 1, or 2, or 3 to 5, or 6, or 7) any subrange between any two explicit values is included (e.g., 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).

[0006] Unless stated to the contrary, implicit from the context, or customary in the art, all components and percents are based on weight, and all test methods are current as of the filing date of this disclosure.

[0007] "Blend," "polymer blend" and like terms is a composition of two or more polymers. Such a blend may or may not be miscible. Such a blend may or may not be phase separated. Such a blend may or may not contain one or more domain configurations, as determined from transmission electron spectroscopy, light scattering, x-ray scattering, and any other method known in the art. Blends are not laminates, but one or more layers of a laminate can comprise a blend.

[0008] "Composition" and like terms is a mixture of two or more materials. Included in compositions are pre-reaction, reaction and post-reaction mixtures, the latter of which will include reaction products and by-products as well as unreacted components of the reaction mixture and decomposition products, if any, formed from the one or more components of the pre-reaction or reaction mixture.

[0009] The terms "comprising," "including," "having," and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, "consisting essentially of" excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability. The term "consisting of" excludes any component, step or procedure not specifically delineated or listed.

[0010] An "ethylene-based polymer" is a polymer that contains more than 50 weight percent polymerized ethylene monomer (based on the total weight of polymerizable monomers) and, optionally, may contain at least one comonomer. Ethylene-based polymer includes ethylene homopolymer, and ethylene copolymer (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used interchangeably. Nonlimiting examples of ethylene-based polymer (polyethylene) include low density polyethylene (LDPE) and linear polyethylene. Nonlimiting examples of linear polyethylene include linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), multi-component ethylene-based copolymer (EPE), ethylene/a-olefin multi-block copolymers (also known as olefin block copolymer (OBC)), single-site catalyzed linear low density polyethylene (m-LLDPE), substantially linear, or linear, plastomers/elastomers, and high density polyethylene (HDPE). Generally, polyethylene may be produced in gas-phase, fluidized bed reactors, liquid phase slurry process reactors, or liquid phase solution process reactors, using a heterogeneous catalyst system, such as Ziegler-Natta catalyst, a homogeneous catalyst system, comprising Group 4 transition metals and ligand structures such as metallocene, non-metallocene metal-centered, heteroaryl, heterovalent aryloxyether, phosphinimine, and others. Combinations of heterogeneous and/or homogeneous catalysts also may be used in either single reactor or dual reactor configurations.

[0011] "High density polyethylene" (or "HDPE") is an ethylene homopolymer or an ethylene/a-olefin copolymer with at least one C₄-Ci₀ a-olefin comonomer, or C₄_C₈ a-olefin comonomer and a density from greater than 0.94 g/cc, or 0.945 g/cc, or 0.95 g/cc, or 0.955 g/cc to 0.96 g/cc, or 0.97 g/cc, or 0.98 g/cc. The HDPE can be a monomodal copolymer or a multimodal copolymer. A "monomodal ethylene copolymer" is an ethylene/C₄-Ci₀ a-olefin copolymer that has one distinct peak in a gel permeation chromatography (GPC) showing the molecular weight distribution. A "multimodal ethylene copolymer" is an ethylene/C₄- Cio a-olefin copolymer that has at least two distinct peaks in a GPC showing the molecular weight distribution. Multimodal includes copolymer having two peaks (bimodal) as well as copolymer having more than two peaks. Nonlimiting examples of HDPE include DOW™ High Density Polyethylene (HDPE) Resins (available from The Dow Chemical Company), ELITE™ Enhanced Polyethylene Resins (available from The Dow Chemical Company), CONTINUUM™ Bimodal Polyethylene Resins (available from The Dow Chemical Company), LUPOLEN™ (available from LyondellBasell), as well as HDPE products from Borealis, Ineos, and ExxonMobil.

[0012] An "interpolymer" is a polymer prepared by the polymerization of at least two different monomers. This generic term includes copolymers, usually employed to refer to polymers prepared from two different monomers, and polymers prepared from more than two different monomers, e.g., terpolymers, tetrapolymers, etc.

[0013] "Low density polyethylene" (or "LDPE") consists of ethylene homopolymer, or ethylene/a-olefin copolymer comprising at least one C₃-Ci₀ a-olefin, preferably C₃-C₄ that has a density from 0.915 g/cc to 0.940 g/cc and contains long chain branching with broad MWD. LDPE is typically produced by way of high pressure free radical polymerization (tubular reactor or autoclave with free radical initiator). Nonlimiting examples of LDPE include MarFlex™ (Chevron Phillips), LUPOLEN™ (LyondellBasell), as well as LDPE products from Borealis, Ineos, ExxonMobil, and others.

[0014] "Linear low density polyethylene" (or "LLDPE") is a linear ethylene/a-olefin copolymer containing heterogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C₃-Ci₀ a-olefin comonomer or at least one C₄-C₈ α-olefin comonomer, or at least one C₆-C₈ α-olefin comonomer. LLDPE is characterized by little, if any, long chain branching, in contrast to conventional LDPE. LLDPE has a density from 0.910 g/cc, or 0.915 g/cc, or 0.920 g/cc, or 0.925 g/cc to 0.930 g/cc, or 0.935 g/cc, or 0.940 g/cc. Nonlimiting examples of LLDPE include TUFLIN™ linear low density polyethylene resins (available from The Dow Chemical Company), DOWLEX™ polyethylene resins (available from the Dow Chemical Company), and MARLEX™ polyethylene (available from Chevron Phillips). [0015] "Ultra low density polyethylene" (or "ULDPE") and "very low density polyethylene" (or "VLDPE") each is a linear ethylene/a-olefin copolymer containing heterogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C₃-Ci₀ a-olefin comonomer, or at least one C₄-C₈ a- olefin comonomer, or at least one C₆-C₈ a-olefin comonomer. ULDPE and VLDPE each has a density from 0.885 g/cc, or 0.90 g/cc to 0.915 g/cc. Nonlimiting examples of ULDPE and VLDPE include ATTANE™ ultra low density polyethylene resins (available form The Dow Chemical Company) and FLEXOMER™ very low density polyethylene resins (available from The Dow Chemical Company).

[0016] "Multi-component ethylene-based copolymer" (or "EPE") comprises units derived from ethylene and units derived from at least one C₃-Ci₀ α-olefin comonomer, or at least one C₄-C₈ α-olefin comonomer, or at least one C₆-C₈ α-olefin comonomer, such as described in patent references USP 6,111,023; USP 5,677,383; and USP 6,984,695. EPE resins have a density from 0.905 g/cc, or 0.908 g/cc, or 0.912 g/cc, or 0.920 g/cc to 0.926 g/cc, or 0.929 g/cc, or 0.940 g/cc, or 0.962 g/cc. Nonlimiting examples of EPE resins include ELITE™ enhanced polyethylene (available from The Dow Chemical Company), SURPASS™ Polyethylene (PE) Resins (available from Nova Chemicals), and SMART™ (available from SK Chemicals Co.).

[0017] "Single-site catalyzed linear low density polyethylenes" ( or "m-LLDPE") are linear ethylene/a-olefin copolymers containing homogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C₃-Ci₀ a-olefin comonomer, or at least one C₄-C₈ α-olefin comonomer, or at least one C₆-C₈ a-olefin comonomer. m-LLDPE has density from 0.913 g/cc, or 0.918 g/cc, or 0.920 g/cc to 0.925 g/cc, or 0.940 g/cc. Nonlimiting examples of m-LLDPE include EXCEED™ metallocene PE (available from ExxonMobil Chemical), LUFLEXEN™ m-LLDPE (available from LyondellBasell), and ELTEX™ PF m-LLDPE (available from Ineos Olefins & Polymers).

[0018] "Ethylene plastomers/elastomers" are substantially linear, or linear, ethylene/a- olefin copolymers containing homogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C₃-Ci₀ α-olefin comonomer, or at least one C₄-C₈ a-olefin comonomer, or at least one C₆-C₈ a-olefin comonomer. Ethylene plastomers/elastomers have a density from 0.870 g/cc, or 0.880 g/cc, or 0.890 g/cc to 0.900 g/cc, or 0.902 g/cc, or 0.904 g/cc, or 0.909 g/cc, or 0.910 g/cc, or 0.917 g/cc. Nonlimiting examples of ethylene plastomers/ elastomers include AFFINITY™ plastomers and elastomers (available from The Dow Chemical Company), EXACT™ Plastomers (available from ExxonMobil Chemical), Tafmer™ (available from Mitsui), Nexlene™ (available from SK Chemicals Co.), and Lucene™ (available LG Chem Ltd.).

[0019] An "olefin-based polymer," as used herein, is a polymer that contains more than 50 weight percent polymerized olefin monomer (based on total amount of polymerizable monomers), and optionally, may contain at least one comonomer. Nonlimiting examples of olefin-based polymer include ethylene-based polymer and propylene-based polymer.

[0020] A "polymer" is a compound prepared by polymerizing monomers, whether of the same or a different type, that in polymerized form provide the multiple and/or repeating "units" or "mer units" that make up a polymer. The generic term polymer thus embraces the term homopolymer, usually employed to refer to polymers prepared from only one type of monomer, and the term copolymer, usually employed to refer to polymers prepared from at least two types of monomers. It also embraces all forms of copolymer, e.g., random, block, etc. The terms "ethylene/a-olefin polymer" and "propylene/a-olefin polymer" are indicative of copolymer as described above prepared from polymerizing ethylene or propylene respectively and one or more additional, polymerizable a-olefin monomer. It is noted that although a polymer is often referred to as being "made of" one or more specified monomers, "based on" a specified monomer or monomer type, "containing" a specified monomer content, or the like, in this context the term "monomer" is understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species. In general, polymers herein are referred to has being based on "units" that are the polymerized form of a corresponding monomer.

[0021] A "propylene-based polymer" is a polymer that contains more than 50 weight percent polymerized propylene monomer (based on the total amount of polymerizable monomers) and, optionally, may contain at least one comonomer. TEST METHODS

[0022] Apparent density. A sample material is cut into a square piece of 38 cm ^χ 38 cm (15 in x 15 in) in size. The volume of this piece is calculated from the thickness measured at four points. The division of the weight by the volume gives the apparent density (an average of four measurements is taken) with values reported in grams per cubic centimeter, g/cc.

[0023] Bending Stiffness. The bending stiffness is measured in accordance with DIN 53121 standard, with compression molded plaques of 550 μιη thickness, using a Frank-PTI Bending Tester. The samples are prepared by compression molding of resin granules per ISO 293 standard. Conditions for compression molding are chosen per ISO 1872 - 2007 standard. The average cooling rate of the melt is 15°C/min. Bending stiffness is measured in 2-point bending configuration at room temperature with a span of 20 mm, a sample width of 15 mm, and a bending angle of 40°. Bending is applied at 6°/second (s) and the force readings are obtained from 6 to 600 s, after the bending is complete. Each material is evaluated four times with results reported in Newton millimeters ("Nmm").

[0024] ¹³C Nuclear Magnetic Resonance (NMR)

[0025] Sample Preparation

[0026] The samples are prepared by adding approximately 2.7 g of a 50/50 mixture of tetrachloroethane-d2/orthodichlorobenzene that is 0.025M in chromium acetylacetonate (relaxation agent) to 0.21 g sample in a 10 mm NMR tube. The samples are dissolved and homogenized by heating the tube and its contents to 150°C.

[0027] Data Acquisition Parameters

[0028] The data is collected using a Bruker 400 MHz spectrometer equipped with a Bruker Dual DUL high-temperature CryoProbe. The data is acquired using 320 transients per data file, a 7.3 sec pulse repetition delay (6 sec delay+1.3 sec acq. time), 90 degree flip angles, and inverse gated decoupling with a sample temperature of 125°C. All measurements are made on non-spinning samples in locked mode. Samples are homogenized immediately prior to insertion into the heated (130°C) NMR Sample changer, and are allowed to thermally equilibrate in the probe for 15 minutes prior to data acquisition.

[0029] Crystallization Elution Fractionation (CEF) Method

[0030] Comonomer distribution analysis is performed with Crystallization Elution Fractionation (CEF) (PolymerChar in Spain) (B Monrabal et a I, Macromol. Symp. 257, 71-79 (2007)). Ortho-dichlorobenzene (ODCB) with 600 ppm antioxidant butylated hydroxytoluene (BHT) is used as solvent. Sample preparation is done with autosampler at 160°C for 2 hours under shaking at 4 mg/ml (unless otherwise specified). The injection volume is 300 μιη. The temperature profile of CEF is: crystallization at 3°C/min from 110°C to 30°C, the thermal equilibrium at 30°C for 5 minutes, elution at 3°C/min from 30°C to 140°C. The flow rate during crystallization is at 0.052 ml/min. The flow rate during elution is at 0.50 ml/min. The data is collected at one data point/second. CEF column is packed by the Dow Chemical Company with glass beads at 125 μιη + 6% (MO-SCI Specialty Products) with 1/8 inch stainless tubing. Glass beads are acid washed by MO-SCI Specialty with the request from The Dow Chemical Company. Column volume is 2.06 ml. Column temperature calibration is performed by using a mixture of NIST Standard Reference Material Linear polyethylene 1475a (1.0 mg/ml) and Eicosane (2 mg/ml) in ODCB. Temperature is calibrated by adjusting elution heating rate so that NIST linear polyethylene 1475a has a peak temperature at 101.0°C, and Eicosane has a peak temperature of 30.0°C. The CEF column resolution is calculated with a mixture of NIST linear polyethylene 1475a (1.0 mg/ml) and hexacontane (Fluka, purum, >97.0 , 1 mg/ml ). A baseline separation of hexacontane and NIST polyethylene 1475a is achieved. The area of hexacontane (from 35.0 to 67.0°C) to the area of NIST 1475a from 67.0 to 110.0°C is 50 to 50, the amount of soluble fraction below 35.0°C is <1.8 wt%. The CEF column resolution is defined in the following equation:

Resolution

Peak temperature of NIST 1475a - Peak Temperature of Hexacontane Half — height Width of NIST 1475a + Half — height Width of Hexacontane

[0031] where the column resolution is 6.0. [0032] Density is measured in accordance with ASTM D 792 with values reported in grams per cubic centimeter, g/cc.

[0033] Differential Scanning Calorimetry (DSC). Differential Scanning Calorimetry (DSC) is used to measure the melting and crystallization behavior of a polymer over a wide range of temperatures. For example, the TA Instruments Q1000 DSC, equipped with an RCS (refrigerated cooling system) and an autosampler is used to perform this analysis. During testing, a nitrogen purge gas flow of 50 ml/min is used. Each sample is melt pressed into a thin film at about 175°C; the melted sample is then air-cooled to room temperature (approx. 25°C). The film sample is formed by pressing a "0.1 to 0.2 gram" sample at 175°C at 1,500 psi, and 30 seconds, to form a "0.1 to 0.2 mil thick" film. A 3-10 mg, 6 mm diameter specimen is extracted from the cooled polymer, weighed, placed in a light aluminum pan (ca 50 mg), and crimped shut. Analysis is then performed to determine its thermal properties. The thermal behavior of the sample is determined by ramping the sample temperature up and down to create a heat flow versus temperature profile. First, the sample is rapidly heated to 180°C, and held isothermal for five minutes, in order to remove its thermal history. Next, the sample is cooled to -40°C, at a 10°C/minute cooling rate, and held isothermal at -40°C for five minutes. The sample is then heated to 150°C (this is the "second heat" ramp) at a 10°C/minute heating rate. The cooling and second heating curves are recorded. The cool curve is analyzed by setting baseline endpoints from the beginning of crystallization to -20°C. The heat curve is analyzed by setting baseline endpoints from -20°C to the end of melt. The values determined are peak melting temperature (Tm), peak crystallization temperature (Tc), onset crystallization temperature (Tc onset), heat of fusion (Hf) (in Joules per gram), the calculated % crystallinity for polyethylene samples using: % Crystallinity for PE = ((Hf)/(292 J/g)) x 100, and the calculated % crystallinity for polypropylene samples using: % Crystallinity for PP = ((Hf)/165 J/g)) x 100. The heat of fusion (Hf) and the peak melting temperature are reported from the second heat curve. Peak crystallization temperature and onset crystallization temperature are determined from the cooling curve. [0034] Elastic Recovery. Resin pellets are compression molded following ASTM D4703, Annex Al, Method C to a thickness of approximately 5-10 mil. Microtensile test specimens of geometry as detailed in ASTM D1708 are punched out from the molded sheet. The test specimens are conditioned for 40 hours prior to testing in accordance with Procedure A of Practice D618.

[0035] The samples are tested in a screw-driven or hydraulically-driven tensile tester using flat, rubber faced grips. The grip separation is set at 22 mm, equal to the gauge length of the microtensile specimens. The sample is extended to a strain of 100% at a rate of 100%/min and held for 30s. The crosshead is then returned to the original grip separation at the same rate and held for 60s. The sample is then strained to 100% at the same 100%/min strain rate.

[0036] Elastic recovery may be calculated as follows: Initial Applied Strain— Permanent Set)

Elastic Recovery = x 100%

Initial Applied Strain

[0037] Melt flow rate (MFR) is measured in accordance with ASTM D 1238, Condition 280°C/2.16 kg (g/10 minutes).

[0038] Melt index (Ml) is measured in accordance with ASTM D 1238, Condition 190°C/2.16 kg (g/10 minutes).

[0039] "Melting Point" or "Tm" as used herein (also referred to as a melting peak in reference to the shape of the plotted DSC curve) is typically measured by the DSC (Differential Scanning Calorimetry) technique for measuring the melting points or peaks of polyolefins as described in USP 5,783,638. It should be noted that many blends comprising two or more polyolefins will have more than one melting point or peak, many individual polyolefins will comprise only one melting point or peak.

[0040] Molecular weight distribution (Mw/Mn) is measured using Gel Permeation Chromatography (GPC). In particular, conventional GPC measurements are used to determine the weight-average (Mw) and number-average (Mn) molecular weight of the polymer and to determine the Mw/Mn. The gel permeation chromatographic system consists of either a Polymer Laboratories Model PL-210 or a Polymer Laboratories Model PL- 220 instrument. The column and carousel compartments are operated at 140°C. Three Polymer Laboratories 10-micron Mixed-B columns are used. The solvent is 1,2,4 trichlorobenzene. The samples are prepared at a concentration of 0.1 grams of polymer in 50 milliliters of solvent containing 200 ppm of butylated hydroxytoluene (BHT). Samples are prepared by agitating lightly for 2 hours at 160°C. The injection volume used is 100 microliters and the flow rate is 1.0 ml/minute.

[0041] Calibration of the GPC column set is performed with 21 narrow molecular weight distribution polystyrene standards with molecular weights ranging from 580 to 8,400,000, arranged in 6 "cocktail" mixtures with at least a decade of separation between individual molecular weights. The standards are purchased from Polymer Laboratories (Shropshire, UK). The polystyrene standards are prepared at 0.025 grams in 50 milliliters of solvent for molecular weights equal to or greater than 1,000,000, and 0.05 grams in 50 milliliters of solvent for molecular weights less than 1,000,000. The polystyrene standards are dissolved at 80°C with gentle agitation for 30 minutes. The narrow standards mixtures are run first and in order of decreasing highest molecular weight component to minimize degradation. The polystyrene standard peak molecular weights are converted to polyethylene molecular weights using the following equation (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)):

645(Mp₀|_ystyrene)-

[0042] Polypropylene equivalent molecular weight calculations are performed using Viscotek TriSEC software Version 3.0.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is a perspective view of a sheet of three-dimensional random loop material in accordance with an embodiment of the present disclosure.

[0044] FIG. 1A is an enlarged perspective view of Area 1A of FIG. 1.

[0045] FIG. 2 is a cross-sectional view of a bicomponent fiber in a side-by-side configuration in accordance with an embodiment of the present disclosure.

[0046] FIG. 3 is a cross-sectional view of a bicomponent fiber in a core-sheath configuration in accordance with an embodiment of the present disclosure. [0047] FIG. 3A is a cross-sectional view of a bicomponent fiber in an eccentric core- sheath configuration in accordance with an embodiment of the present disclosure.

[0048] FIG. 4 is a cross-sectional view of a bicomponent fiber in an islands in the sea configuration in accordance with an embodiment of the present disclosure.

[0049] FIG. 5 is a cross-sectional view of a bicomponent fiber in a segmented pie configuration in accordance with an embodiment of the present disclosure.

[0050] FIG. 6 is a cross-sectional view of a bicomponent fiber in a tip-core configuration in accordance with an embodiment of the present disclosure.

[0051] FIG. 7 is a cross-sectional view of a bicomponent fiber in a segmented ribbon configuration in accordance with an embodiment of the present disclosure

DETAILED DESCRIPTION

[0052] The present disclosure provides a sheet. The sheet is composed of a three- dimensional random loop material (or "3DRLM"). The 3DRLM includes a web structure of a multitude of winding continuous fibers melt-bonded together at a multitude of contact points to form a multitude of loops. Each continuous fiber includes a component (1) that is an olefin-based polymer having density from 0.86 g/cc to 0.96 g/cc. Each continuous fiber also includes a component (2) that is an olefin-based polymer having a density from 0.86 g/cc to 0.96 g/cc. The 3DRLM has an apparent density from 0.03 g/cc to 0.08 g/cc.

A. Sheet

[0053] FIG. 1 shows a sheet 10 is composed of a three-dimensional random loop material 14. The sheet 10 has a geometric shape. A "geometric shape," as used herein, is a three dimensional shape or a three dimensional configuration having a length, a width, and a height. The geometric shape can be a regular three dimensional shape, an irregular three dimensional shape, and combinations thereof. Nonlimiting examples of regular three- dimensional shapes include cube, prism, sphere, cone, and cylinder. The sheet may be solid or hollow. It is understood that when the geometric shape of the sheet is a prism, the prism can have a cross-sectional shape that is a regular polygon, or an irregular polygon having three, four, five, six, seven, eight, nine, 10 or more sides. It is further understood that when the geometric shape of the sheet is a cylinder, the cylinder can have a cross-sectional shape that is an ellipse or a circle.

B. 3-dimensional random loop material

[0054] The sheet 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 a structure of a multitude of loops 32 formed by allowing continuous fibers 34, to wind, permitting respective loops to come in contact with one another in a molten state and to be heat-bonded, or otherwise melt-bonded, at the contact points 36. Even when a great stress to cause significant deformation is given, the 3DRLM 30 absorbs the stress with the entire net structure composed of three-dimensional random loops melt-integrated, by deforming itself; and once the stress is lifted, elastic resilience of the polymer manifests itself to allow recovery to the original shape of the structure. When a net structure composed of continuous fibers made from a known non-elastic polymer is used as a cushioning material, plastic deformation is developed and the recovery cannot be achieved, thus resulting in poor heat-resisting durability. When the fibers are not melt-bonded at contact points, the shape cannot be retained and the structure does not integrally change its shape, with the result that a fatigue phenomenon occurs due to the concentration of stress, thus degrading durability and deformation resistance. In certain embodiments, melt-bonding is the state where all contact points are melt-bonded.

[0055] A nonlimiting method for producing 3DRLM 30 includes the steps of (a) heating a molten olefin-based polymer, at a temperature 10°C-140°C higher than the melting point of the polymer in a typical melt-extruder; (b) discharging the molten interpolymer to the downward direction from a nozzle with plural orifices to form loops by allowing the fibers to fall naturally (due to gravity). The polymer may be used in combination with a thermoplastic elastomer, thermoplastic non-elastic polymer or a combination thereof. The distance between the nozzle surface and take-off conveyors installed on a cooling unit for solidifying the fibers, melt viscosity of the polymer, diameter of orifice and the amount to be discharged are the elements which decide loop diameter and fineness of the fibers. Loops are formed by holding and allowing the delivered molten fibers to reside between a pair of take-off conveyors (belts, or rollers) set on a cooling unit (the distance therebetween being adjustable), bringing the loops thus formed into contact with one another by adjusting the distance between the orifices to this end such that the loops in contact are heat-bonded, or otherwise melt-bonded, as they form a three-dimensional random loop structure. Then, the continuous fibers, wherein contact points have been heat-bonded as the loops form a three-dimensional random loop structure, are continuously taken into a cooling unit for solidification to give a net structure. Thereafter, the structure is cut into a desired length and shape. The method is characterized in that the olefin-based polymer is melted and heated at a temperature 10°C-140°C higher than the melting point of the interpolymer and delivered to the downward direction in a molten state from a nozzle having plural orifices. When the polymer is discharged at a temperature less than 10°C higher than the melting point, the fiber delivered becomes cool and less fluidic to result in insufficient heat-bonding of the contact points of fibers.

[0056] Properties, such as, the loop diameter and fineness of the fibers constituting the cushioning net structure provided herein depend on the distance between the nozzle surface and the take-off conveyor speed installed on a cooling unit for solidifying the interpolymer, melt viscosity of the interpolymer, diameter of orifice and the amount of the interpolymer to be delivered therefrom. For example, a decreased amount of the interpolymer to be delivered and a lower melt viscosity, larger distance between nozzle and conveyer and higher conveyor speedupon delivery result in smaller fineness of the fibers and smaller average loop diameter of the random loop. On the contrary, a shortened distance between the nozzle surface and the take-off conveyor installed on the cooling unit for solidifying the interpolymer results in a slightly greater fineness of the fiber and a greater average loop diameter of the random loop. Orifice diameter also influences the fiber diameter and the loop diameter. A lower orifice diameter yields finer fibers and smaller loop diameter. Larger orifice diameter yields larger fiber diameter and larger loop diameter. These conditions in combination afford the desirable fineness of the continuous fibers of from 100 denier to 100000 denier and an average diameter of the random loop of not more than 100 mm, or from 1 millimeter (mm), or 2 mm, or 10 mm to 25 mm, or 50 mm. By adjusting the distance to the aforementioned conveyor, the thickness of the structure can be controlled while the heat-bonded net structure is in a molten state and a structure having a desirable thickness and flat surface formed by the conveyors can be obtained. Too great a conveyor speed results in failure to heat-bond the contact points, since cooling proceeds before the heat-bonding. On the other hand, too slow a speed can cause higher density resulting from excessively long dwelling of the molten material. In some embodiments the distance to the conveyor and the conveyor speed should be selected such that the desired apparent density of 0.005-0.1 g/cc or 0.01-0.05 g/cc can be achieved.

[0057] In an embodiment, the 3DRLM 30 has, one, some, or all of the properties (i) - (v) below:

[0058] (i) an apparent density from 0.016 g/cc, or 0.024 g/cc, or 0.03 g/cc, or 0.040 g/cc, or 0.050 g/cc, or 0.060 g/cc to 0.070 g/cc, or 0.080 g/cc, or 0.090 g/cc, or 0.100 g/cc, or 0.150 g/cc; and/or

[0059] (ii) a fiber diameter from 0.1 mm, or 0.5 mm, or 0.7 mm, or 1.0 mm or 1.5 mm to 2.0 mm to 2.5 mm, or 3.0 mm; and/or

[0060] (iii) a thickness (machine direction) from 1.0 cm, 2.0 cm, or 3.0, cm, or 4.0 cm, or 5.0 cm, or 10 cm, or 20 cm to 25 cm, or 30 cm, or 35cm, or 40 cm, or 45 cm, or 50 cm; and/or

[0061] (iv) a fiber a linear density from 1000 dpf, or 5000, or 10,000 to 20,000, or 30,000 dpf.

[0062] It is understood that the thickness of the 3DRLM 30 will vary based on the application for the sheet.

[0063] The 3DRLM 30 is formed into a three dimensional geometric shape to form a sheet (i.e., a prism). The 3DRLM 30 is an elastic material which can be compressed and stretched and return to its original geometric shape. An "elastic material," as used herein, is a rubber-like material that can be compressed and/or stretched and which expands/retracts very rapidly to approximately its original shape/length when the force exerting the compression and/or the stretching is released. The three dimensional random loop material 30 has a "neutral state" when no compressive force and no stretch force is imparted upon the 3DRLM 30. The three dimensional random loop material 30 has "a compressed state" when a compressive force is imparted upon the 3DRLM 30. The three dimensional random loop material 30 has "a stretched state" when a stretching force is imparted upon the 3DRLM 30.

C. Component (1)

[0064] Each continuous fiber 34 in the 3DRLM 30 is composed of a component (1) and a component (2). Component (1) is an olefin-based polymer having a density from 0.86 g/cc to 0.96 g/cc. Component (1) is a non-functionalized olefin-based polymer. A "non- functionalized olefin-based polymer" is an olefin-based polymer lacking a functional group. In other words, the non-functionalized olefin-based polymer consists of only carbon and hydrogen atoms and is void of heteroatoms. A "heteroatom" is an atom other than carbon or hydrogen. Nonlimiting examples of heteroatoms are non-carbon atoms from Groups IV, V, VI and VII of the Periodic Table. Nonlimiting examples of heteroatoms include: F, N, O, P, B, S, and Si.

[0065] The olefin-based polymer of component (1) can be an ethylene-based polymer, a propylene-based polymer, and blends thereof. The olefin-based polymer of component (1) has a density from 0.86 g/cc to 0.96 g/cc, or a density from 0.90 g/cc, or 0.91 g/cc, or 0.92 g/cc, or 0.93 g/cc to 0.94 g/cc, or 0.95 g/cc, or 0.96 g/cc. In an embodiment, component (1) is an ethylene-based polymer having a density from 0.90 g/cc, or 0.91 g/cc, or 0.92 g/cc, or 0.93 g/cc to 0.94 g/cc, or 0.95 g/cc, or 0.96 g/cc and the ethylene-based polymer is non- functionalized as disclosed above. The ethylene-based polymer can be an ethylene homopolymer or an ethylene/a-olefin copolymer. The a-olefin is a C₃-C₂o a-olefin, or a C₄-Ci₂ a- olefin, or a C₄-C₈ a-olefin. Nonlimiting examples of suitable α-olefin comonomer include propylene, butene, methyl-l-pentene, hexene, octene, decene, dodecene, tetradecene, hexadecene, octadecene, cyclohexyl-l-propene (allyl cyclohexane), vinyl cyclohexane, and combinations thereof.

[0066] In an embodiment, component (1) is a high density polyethylene (HDPE) that is an ethylene/ C₄-C₈ α-olefin copolymer. [0067] In an embodiment, component (1) is a linear low density polyethylene that is ethylene/ C₄-C₈ a-olefin copolymer.

[0068] In an embodiment, the olefin-based polymer of component (1) is a propylene- based polymer having a density from 0.90 g/cc to 0.96 g/cc and the propylene-based polymer is non-functionalized as disclosed above. The propylene-based polymer can be a propylene homopolymer or a propylene/a-olefin copolymer. The a-olefin is a C₂ a-olefin, or a C₄-C₂₀ a-olefin, or a C₄-Ci₂ a-olefin, or a C₄-C₈ a-olefin.

D. Component (2)

[0069] Each continuous fiber 34 in the 3DRLM 30 is composed of a component (1) and a component (2). Component (2) is a non-functionalized olefin-based polymer having a density a density from 0.86 g/cc to 0.96 g/cc, or from 0.86 g/cc, or 0.87 g/cc to 0.88 g/cc, or 0.89 g/cc. Component (2) is a different polymeric material than component (1).

[0070] In an embodiment, component (2) is a non-functionalized ethylene-based polymer that is an ethylene/a-olefin polymer having a density from 0.86 g/cc, or 0.87 g/cc to 0.88g/cc, or 0.89 g/cc. Ethylene/a-olefin copolymer may be a random ethylene/a-olefin polymer or an ethylene/a-olefin multi-block polymer. The a-olefin is a C₃-C₂₀ α-olefin , or a C₄-C₁₂ a-olefin, or a C₄-C₈ a-olefin. Nonlimiting examples of suitable α-olefin comonomer include propylene, butene, methyl-l-pentene, hexene, octene, decene, dodecene, tetradecene, hexadecene, octadecene, cyclohexyl-l-propene (allyl cyclohexane), vinyl cyclohexane, and combinations thereof.

[0071] In an embodiment, component (2) is an ethylene/C₄-C₈ α-olefin copolymer that is an elastomer. An "elastomer," as used herein, refers to a rubber-like polymer that can be stretched to at least twice its original length and which retracts very rapidly to approximately its original length when the force exerting the stretching is released. An elastomer has an elastic modulus of about 10,000 psi (68.95 MPa) or less and an elongation usually greater than 200% in the uncrosslinked state at room temperature using the method of ASTM D638 - 72. In an embodiment, component (2) is an "ethylene-based elastomer" which is an elastomer composed of least 50 wt% units derived from ethylene. [0072] In an embodiment, component (2) is an ethylene/C₄-C₈ a-olefin copolymer with a Comonomer Distribution Constant (CDC) in the range of from greater than 45 to less than 400, the ethylene/C₄-C₈ a-olefin copolymer having less than 120 total unsaturation unit/l,000,000C (hereafter referred to as "CDC45-ethylene copolymer"). Nonlimiting examples of suitable CDC45- ethylene copolymer are found in US Patent Nos. 8372931 and 8829115, the entire content of each incorporated by reference herein.

[0073] In an embodiment, the CDC45-ethylene copolymer has one, some, or all of the following properties (i) - (iv) below:

[0074] (i) a density from 0.86 g/cc, or 0.87 g/cc to 0.88 g/cc, or 0.89 g/cc; and/or

[0075] (ii) a zero shear viscosity ratio (ZSVR) of at least 2; and/or

[0076] (iii) less than 20 vinylidene unsaturation unit/l,000,000C; and/or

[0077] (iv) a bimodal molecular weight distribution.

[0078] In an embodiment, component (2) is an ethylene-based polymer that is an ethylene/a-olefin multi-block copolymer. The term "ethylene/a-olefin multi-block copolymer" refers to an ethylene/C₄-C₈ a-olefin multi-block copolymer consisting of ethylene and one copolymerizable C₄-C₈ α-olefin comonomer in polymerized form (and optional additives), the polymer characterized by multiple blocks or segments of two polymerized monomer units differing in chemical or physical properties, the blocks joined (or covalently bonded) in a linear manner, that is, a polymer comprising chemically differentiated units which are joined end-to-end with respect to polymerized ethylenic functionality. Ethylene/a-olefin multi-block copolymer includes block copolymer with two blocks (di-block) and more than two blocks (multi-block). The C₄-C₈ α-olefin is selected from butene, hexene, and octene. The ethylene/a-olefin multi-block copolymer is void of, or otherwise excludes, styrene (i.e., is styrene-free), and/or vinyl aromatic monomer, and/or conjugated diene. When referring to amounts of "ethylene" or "comonomer" in the copolymer, it is understood that this refers to polymerized units thereof. In some embodiments, the ethylene/a-olefin multi-block copolymer can be represented by the following formula: (AB)n ; where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, "A" represents a hard block or segment, and "B" represents a soft block or segment. The As and Bs are linked, or covalently bonded, in a substantially linear fashion, or in a linear manner, as opposed to a substantially branched or substantially star-shaped fashion. In other embodiments, A blocks and B blocks are randomly distributed along the polymer chain. In other words, the block copolymers usually do not have a structure as follows: AAA-AA-BBB-BB. In an embodiment, the ethylene/a-olefin multi-block copolymer does not have a third type of block, which comprises different comonomer(s). In another embodiment, each of block A and block B has monomers or comonomers substantially randomly distributed within the block. In other words, neither block A nor block B comprises two or more sub-segments (or sub-blocks) of distinct composition, such as a tip segment, which has a substantially different composition than the rest of the block.

[0079] Preferably, ethylene comprises the majority mole fraction of the whole ethylene/a-olefin multi-block copolymer, i.e., ethylene comprises at least 50 wt% of the whole ethylene/a-olefin multi-block copolymer. More preferably, ethylene comprises at least 60 wt%, at least 70 wt%, or at least 80 wt%, with the substantial remainder of the whole ethylene/a-olefin multi-block copolymer comprising the C₄-C₈ a-olefin comonomer. In an embodiment, the ethylene/a-olefin multi-block copolymer contains 50 wt% to 90 wt% ethylene, or 60 wt% to 85 wt% ethylene, or 65 wt% to 80 wt% ethylene. For many ethylene/octene multi-block copolymers, the composition comprises an ethylene content greater than 80 wt% of the whole ethylene/octene multi-block copolymer and an octene content of from 10 wt% to 15 wt%, or from 15 wt% to 20 wt% of the whole multi-block copolymer.

[0080] The ethylene/a-olefin multi-block copolymer includes various amounts of "hard" segments and "soft" segments. "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%, based on the weight of the polymer, up to 100 wt%. 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 include all, or substantially all, units derived from ethylene. "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 an 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 100 wt%.

[0081] The soft segments can be present in an ethylene/a-olefin multi-block copolymer from 1 wt% to 99 wt% of the total weight of the ethylene/a-olefin multi-block copolymer, or from 5 wt% to 95 wt%, from 10 wt% to 90 wt%, from 15 wt% to 85 wt%, from 20 wt% to 80 wt%, from 25 wt% to 75 wt%, from 30 wt% to 70 wt%, from 35 wt% to 65 wt%, from 40 wt% to 60 wt%, or from 45 wt% to 55 wt% of the total weight of the ethylene/a-olefin multi-block copolymer. Conversely, the hard segments can be present in similar ranges. The soft segment weight percentage and the hard segment weight percentage can be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed in, for example, USP 7,608,668, entitled "Ethylene/a-Olefin Block Inter-Polymers," filed on March 15, 2006, in the name of Colin L. P. Shan, Lonnie Hazlitt, et. al. and assigned to Dow Global Technologies Inc., the disclosure of which is incorporated by reference herein in its entirety. In particular, hard and soft segment weight percentages and comonomer content may be determined as described in column 57 to column 63 of USP 7,608,668.

[0082] The ethylene/a-olefin multi-block copolymer comprises two or more chemically distinct regions or segments (referred to as "blocks") joined (or covalently bonded) in a linear manner, that is, it contains chemically differentiated units which are joined end-to- end with respect to polymerized ethylenic functionality, rather than in pendent or grafted fashion. In an embodiment, the blocks differ in the amount or type of incorporated comonomer, density, amount of crystallinity, crystallite size attributable to a polymer of such composition, type or degree of tacticity (isotactic or syndiotactic), regio-regularity or regio-irregularity, amount of branching (including long chain branching or hyper-branching), homogeneity or any other chemical or physical property. Compared to block interpolymers of the prior art, including interpolymers produced by sequential monomer addition, fluxional catalysts, or anionic polymerization techniques, the present ethylene/a-olefin multi-block copolymer is characterized by unique distributions of both polymer polydispersity (PDI or Mw/Mn or MWD), polydisperse block length distribution, and/or polydisperse block number distribution, due, in an embodiment, to the effect of the shuttling agent(s) in combination with multiple catalysts used in their preparation.

[0083] In an embodiment, the ethylene/a-olefin multi-block copolymer is produced in a continuous process and possesses a polydispersity index (Mw/Mn) from 1.7 to 3.5, or from 1.8 to 3, or from 1.8 to 2.5, or from 1.8 to 2.2. When produced in a batch or semi-batch process, the ethylene/a-olefin multi-block copolymer possesses Mw/Mn from 1.0 to 3.5, or from 1.3 to 3, or from 1.4 to 2.5, or from 1.4 to 2.

[0084] In addition, the ethylene/a-olefin multi-block copolymer possesses a PDI (or Mw/Mn) fitting a Schultz-Flory distribution rather than a Poisson distribution. The present ethylene/a-olefin multi-block copolymer has both a polydisperse block distribution as well as a polydisperse distribution of block sizes. This results in the formation of polymer products having improved and distinguishable physical properties. The theoretical benefits of a polydisperse block distribution have been previously modeled and discussed in Potemkin, Physical Review E (1998) 57 (6), pp. 6902-6912, and Dobrynin, J. Chem. Phvs. (1997) 107 (21), pp 9234-9238.

[0085] In an embodiment, the present ethylene/a-olefin multi-block copolymer possesses a most probable distribution of block lengths.

[0086] In a further embodiment, the ethylene/a-olefin multi-block copolymer of the present disclosure, especially those made in a continuous, solution polymerization reactor, possess a most probable distribution of block lengths. In one embodiment of this disclosure, ethylene/a-olefin multi-block copolymers are defined as having:

(A) Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, where in the numerical values of Tm and d correspond to the relationship:

Tm > -2002.9 + 4538.5(d) - 2422.2(d)², and/or (B) Mw/Mn from about 1.7 to about 3.5, and is characterized by a heat of fusion, ΔΗ in J/g, and a delta quantity, ΔΤ, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest Crystallization Analysis Fractionation ("CRYSTAF") peak, wherein the numerical values of ΔΤ and ΔΗ have the following relationships:

ΔΤ > -0.1299 ΔΗ + 62.81 for ΔΗ greater than zero and up to 130 J/g

ΔΤ > 48°C for ΔΗ greater than 130 J/g

wherein the CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30°C; and/or

(C) elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene/a-olefin interpolymer, and has a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when ethylene/a-olefin interpolymer is substantially free of crosslinked phase:

Re > 1481 - 1629(d); and/or

(D) has a molecular fraction which elutes between 40°C and 130°C when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer has the same comonomer(s) and has a melt index, density and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/a-olefin interpolymer; and/or

(E) has a storage modulus at 25°C, G'(25°C), and a storage modulus at 100°C, G'(100°C), wherein the ratio of G'(25°C) to G'(100°C) is in the range of 1:1 to 9:1.

[0087] The ethylene/a-olefin multi-block copolymer may also have:

(F) a molecular fraction which elutes between 40°C and 130°C when fractionated using TREF, characterized in that the fraction has a block index of at least 0.5 and up to 1 and a molecular weight distribution, Mw/Mn, greater than 1.3; and/or (G) average block index greater than zero and up to 1.0 and a molecular weight distribution, Mw/Mn greater than 1.3.

[0088] It is understood that the ethylene/a-olefin multi-block copolymer may have one, some, all, or any combination of properties (A)-(G). Block Index can be determined as described in detail in USP 7,608,668 herein incorporated by reference for that purpose. Analytical methods for determining properties (A) through (G) are disclosed in, for example, USP 7,608,668, col. 31 line 26 through col. 35 line 44, which is herein incorporated by reference for that purpose.

[0089] In an embodiment, the ethylene/a-olefin multi-block copolymer has hard segments and soft segments, is styrene-free, consists of only (i) ethylene and (ii) a C₄-C₈ a- olefin (and optional additives), and is defined as having a Mw/Mn from 1.7 to 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of Tm and d correspond to the relationship:

Tm > -2002.9 + 4538.5(d) - 2422.2(d)²,

where the density, d, is from 0.850 g/cc, or 0.860 g/cc, or 0.870 g/cc to 0.875 g/cc, or 0.877 g/cc, or 0.880 g/cc, or 0.890 g/cc; and the melting point, Tm, is from 110°C, or 115°C, or 120°C to 125°C, or 130°C, or 135°C.

[0090] In an embodiment, the ethylene/a-olefin multi-block copolymer is an ethylene/l-octene multi-block copolymer (consisting only of ethylene and octene comonomer) and has one, some, or all of the following properties:

(i) a Mw/Mn from 1.7, or 1.8 to 2.2, or 2.5, or 3.5; and/or

(ii) a density from 0.860 g/cc, or 0.865 g/cc, or 0.870 g/cc, or 0.877 g/cc, or 0.880 g/cc; and/or

(iii) a melting point, Tm, from 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 (Ml) from 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) 50-85 wt% soft segment and 40-15 wt% hard segment; and/or (vi) from 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% C₄-Ci₂ a-olefin in the soft segment; and/or

(vii) from 0.5 mol%, or 1.0 mol%, or 2.0 mol%, or 3.0 mol% to 4.0 mol%, or 5 mol%, or 6 mol%, or 7 mol%, or 9 mol% octene in the hard segment; and/or

(viii) an elastic recovery (Re) from 50%, or 60% to 70%, or 80%, or 90%, at 300% 300% min ¹ deformation rate at 21°C as measured in accordance with ASTM D 1708; and/or

(ix) a polydisperse distribution of blocks and a polydisperse distribution of block sizes.

[0091] In an embodiment, the ethylene/a-olefin multi-block copolymer is an ethylene/octene multi-block copolymer. The ethylene/octene multi-block copolymer is sold under the tradename INFUSE™, available from The Dow Chemical Company, Midland, Michigan, USA.

[0092] In an embodiment, the ethylene/a-olefin multi-block copolymer is selected from INFUSE™ 9817, INFUSE™ 9500, and INFUSE™ 9530, available from The Dow Chemical Company.

[0093] In an embodiment, the ethylene/a-olefin multi-block copolymer is INFUSE™ 9817.

[0094] The ethylene/a-olefin multi-block copolymers can be produced via a chain shuttling process such as described in USP 7,858,706, which is herein incorporated by reference. In particular, suitable chain shuttling agents and related information are listed in col. 16 line 39 through col. 19 line 44. Suitable catalysts are described in col. 19 line 45 through col. 46 line 19 and suitable co-catalysts in col. 46 line 20 through col. 51 line 28. The process is described throughout the document, but particularly in col. 51 line 29 through col. 54 line 56. The process is also described, for example, in the following: USP 7,608,668; USP 7,893,166; and USP 7,947,793.

[0095] The base ethylene/a-olefin multi-block copolymer may comprise more than one ethylene/a-olefin multi-block copolymer.

[0096] In an embodiment, component (2) is a propylene based plastomer or elastomer. A "propylene-based plastomer or elastomer" (or "PBPE") is a propylene/ ethylene copolymer, and includes at least 50 weight percent of units derived from propylene and up to 15 wt% ethylene comonomer. All individual values and subranges from 1 wt% to 15 wt% are included and disclosed herein. For example, the ethylene content can be from a lower limit of 1, or 3, or 4, or 5, or 6, or 7 wt% to an upper limit of 8, or 9, or 10, or ll,or 12, or 13, or 14, or 15 wt%.

[0097] The PBPE is produced by polymerizing proplylene and ethylene in the presence of a Group IV metal complex of a polyvalent aryloxyether catalyst. The catalyst of Group IV metal complex of a polyvalent aryloxyether imparts unique properties to the PBPE. In one embodiment, the PBPE is characterized as having substantially isotactic propylene sequences. "Substantially isotactic propylene sequences" means the sequences have an isotactic triad (mm) measured by ¹³C NMR of greater than 0.85, or greater than 0.90, or greater than 0.92, or greater than 0.93. Isotactic triads refer to the isotactic sequence in terms of a triad unit in the copolymer molecular chain determined by ¹³C NMR spectroscopy.

[0098] The PBPE has a B-value less than 1.0 or less than 0.99, or less than 0.98, or less than 0.97. The term "B-value" is a measure of randomness, and measures the distribution of the propylene and ethylene across the polymer chain of the PBPE. B-values range from 0 to 2. The higher the B-value, the more alternating the ethylene distribution in the copolymer. The lower the B-value, the more blocky or clustered the ethylene distribution in the PBPE propylene/ethylene copolymer.

[0099] The B-value as described by Koenig (Spectroscopy of Polymers American Chemical Society, Washington, DC, 1992) is calculated as follows.

B is defined for a propylene / ethylene copolymer as:

where f(EP + PE) = the sum of the EP and PE diad fractions; and Fe and Fp = the mole fraction of ethylene and propylene in the copolymer, respectively. The diad fraction can be derived from triad data according to: f(EP + PE) = [EPE] + [EPP+PPE]/2 + [PEP] + [EEP+PEE]/2. The B-values can be calculated for other copolymers, in an analogous manner, by assignment of the respective copolymer diads. For example, calculation of the B-value for a propylene/l-octene copolymer uses the following equation:

[00100] For PBPE polymers made with a Group IV metal complex of a polyvalent aryloxyether catalyst, the B-values are less than 1.0. In an embodiment, the PBPE has a B- value from 0.90, or 0.92, or 0.93, or 0.94 to 0.95, or 0.96, or 0.97, or 0.98, or 0.99. This means that for PBPE made with the Group IV metal complex of a polyvalent aryloxyether catalyst, not only is the propylene block length relatively long for a given percentage of ethylene, but a substantial amount of long sequences of three or more sequential ethylene insertions are present in the PBPE.

[00101] The PBPE has a total unsaturation, per mole of propylene, from 0.01% to 0.03 %. The total unsaturation per mole of propylene is measured by ¹H NMR analysis as described below.

[00102] ¹H NMR Analysis

[00103] Samples are prepared by adding approximately 3.25g of a 50/50 mixture of tetrachloroethane-d2/perchlorethylene that is 0.0015M in chromium acetylacetonate (relaxation agent) to 0.130g sample in a 10mm NMR tube. The samples are dissolved and homogenized by heating the tube and its contents to 110°C. The data is collected using a Bruker 400 MHz spectrometer, equipped with a Bruker Dual DUL high-temperature CryoProbe. The unsaturation data is collected using 4 scans per data file, a 15.6 second pulse repetition delay, with a sample temperature of 120°C. The acquisition is carried out using spectral width of 10,000Hz and a file size of 16K data points. The presaturation experiment is run with a modified pulse sequence, Iclprf2.zzl using 100 scans per data file.

Calculations

Moles of H from propylene

Mol fraction propylene * (integral area δ 3.5 - 0.2ppm)

Total moles propylene

moles H from propylene

6 protons Mol% vinyl unsaturation/mol propylene

100 * moles vinyl

Total moles propylene

Mol% Cis/Trans Unsaturation/mol propylene

100 * moles cis /trans

Total moles propylene

Mol% trisubstituted unsaturation/mol propylene

100 * moles trisub

Total moles propylene

Mol% vinylidene unsaturation/mol propylene

100 * moles vinylidene

Total moles propylene

Total mol% unsaturation/mol propylene

Mol % vinyl + Mole cis&trans + Mol % trisub + Mol + vinylidene

[00104] The PBPE has a crystallinity in the range from 1 wt% to 40 wt%. For example, the crystallinity can be from 10 wt%, to 15, or 20 to 25, or 30, or 35, or 40 wt%. Crystallinity is measured via DSC method, as described below in the test methods section. The propylene/ethylene copolymer includes units derived from propylene and polymeric units derived from ethylene comonomer and optional C₄-Ci₀ a-olefin. Exemplary comonomers are C₂, and C₄ to Ci₀ a-olefins; for example, C₂, C₄, C₆ and C₈ a-olefins.

[00105] In one embodiment, the PBPE has a heat of fusion (H_f) from 10 J/g to 65 J/g.

[00106] In one embodiment, the PBPE has a density from 0.860 g/cc to 0.890 g/cc, or 0.860 g/cc to 0.870 g/cc, or 0.860 g/cc to 0.865 g/cc.

[00107] In one embodiment, the PBPE has melting temperature, Tm, from 50°C to 100°C, or 60°C to 90°C, or 60°C to 80°C, or 65°C to 75°C.

[00108] In one embodiment, the PBPE has a weight average molecular weight (Mw) from 20,000 to 50,000 g/mole, further from 24,000 to 50,000 g/mole.

[00109] In one embodiment, the PBPE has a Mw/Mn from 2.0 to 4.0, further from 2.0 to 3.5, further from 2.0 to 3.0, further from 2.0 to 2.5.

[00110] In an embodiment, the PBPE has one, some, or all of the following properties: (i) from 80 wt% to 99 wt% units derived from propylene and from 20 wt% to 1 wt% units derived from ethylene; and/or

(ii) an isotactic triad (mm) measured by ¹³C NMR greater than 0.92; and/or

(iii) a Koenig B-value from 0.93 to 0.97; and/or

(iv) a total mol% unsaturation propylene from 0.018% to 0.025%, further from 0.019% to 0.025%; and/or

(v) a density from 0.860 g/cc or 0.865 g/cc to 0.870, or 0.875, or 0.880 g/cc; and/or

(vi) a melting temperature, Tm from 60°C to 75°C, further from 60°C to 72°C, further from 60°C to 70°C; and/or

(vii) a heat of fusion (H_f) from 40 J/g to 80 J/g; and/or

(viii) a crystallinity from 5% to 15%, further from 5% to 10%; and/or

(ix) an Mw from 20,000 to 50,000 g/mole, further from 25,000 to 50,000 g/mole, further from 30,000 to 50,000 g/mole; and/or

(x) a Mw/Mn from 2.0 to 3.0, further from 2.0 to 2.7, further from 2.0 to 2.5.

[00111] The PBPE may comprise two or more embodiments disclosed herein.

[00112] In an embodiment, for each fiber, component 1 has a first melt temperature, Tml, and component (2) has a second melt temperature, Tm2. The components (1) and (2) in each fiber have a change in Tm, ΔΤιη, from 0 to 10. The term "ΔΤιη," as used herein, is the absolute value of the difference between the melt temperature of component (1), Tml, and the melt temperature of component (2), Tm2, wherein melt temperature is reported in °C. The term ΔΤιη is defined by Equation (2) below.

Equation (2)

ATm= | Tml-Tm2 | = 0°C to 10°C.

[00113] In an embodiment, ΔΤιτι is from 0°C, or 1°C, or 2°C, or 3°C, or 4°C to 5°C, or 6°C, or 7°C, or 8°C, or 9°C, or less than 10°C.

[00114] In an embodiment, the fibers have a side-by-side configuration. FIG. 2, shows a sectional view of fiber 134. In the fiber 134, component (1) forms a first side 140 of the fiber 134. Component (2) forms a second side 142, of the fiber 134. First side 140 (component (1)) and second side 142 (component (2)) extend along the length of the fiber 134, and are integral and inseparable.

[00115] In an embodiment, the fibers have a core-sheath configuration. FIG. 3 shows a sectional view of fiber 234. In the fiber 234, a core 240 is formed from component (1). A sheath 242, formed from component (2) encompasses, or otherwise surrounds, the core 240. along the length of the fiber 234. In other words, the core 240 extends concentrically within the sheath 242 along the length of the fiber 234. Core 240 and sheath 242 extend along the length, or along the entire length, of the fiber 234, and are integral and inseparable.

[00116] In an embodiment, each fiber comprises from 5 vol%, or 10 vol%, or 20 vol%, or 30 vol% to 40 vol%, or 50 vol% of the sheath (component 2) and a reciprocal vol% of the core, or from 95 vol%, or 90 vol%, or 80 vol%, or 70 vol%, to 60 vol%, or 50 vol% of the core (component 1) based on the total volume of the fiber.

[00117] In an embodiment, component (1) of the core is an ethylene-based polymer and the component (2) of the sheath is an ethylene-based polymer. In this way, the sheet 10 of 3DRLM is composed solely of ethylene-based polymer. In a further embodiment, the core that is ethylene-based polymer includes re-grind polyethylene or otherwise known as recycled polyethylene. An "all-polyethylene" sheet 10 is advantageous as it promotes recyclability.

[00118] In an embodiment, the core includes an additive blended into the olefin-based polymer component (1). Nonlimiting examples of suitable additive include stabilizer, processing aid, filler, coloring pigment, sound blocking agent, crosslinking agent, foaming agent, flame retardant, UV inhibitor, antimicrobial agent, and combinations thereof.

[00119] In an embodiment, the core 240 is centrally located within the sheath 242 as shown in FIG. 3.

[00120] In an embodiment, FIG. 3A shows a fiber 234a having a core-sheath configuration whereby a core 240a (composed of component (1)) is non-centrally located within the sheath 242a (composed of component (2)). [00121] In an embodiment, the fibers have an islands in the sea configuration. FIG. 4 shows a sectional view of a fiber 334 composed of a plurality of cores 340 (formed from component (1)). The plurality of cores 340 are separated from each other and are disposed in a sheath 342 composed of component (2). The plurality of cores 340 form discrete "islands" within the "sea" which is the sheath 342. The component (2) material of the sheath 342 separates the plurality of cores from each other. The component (2) material of the sheath 342 also surrounds, or otherwise encases, the plurality of cores 340. The plurality cores 340 ("islands") and sheath 242 ("sea") extend along the length, or along the entire length, of the fiber 334, and are integral and inseparable.

[00122] In an embodiment, the fibers have a segmented pie configuration. FIG. 5 shows a sectional view of a fiber 434 composed of a plurality of first pie segments 440. The first pie segments are composed of component (1). The fiber 434 also includes a plurality of second pie segments 442. The second pie segments 442 are composed of component (2). Each pie segment 440, 442 extends from a center point of the fiber and extends radially outward to the outer surface of the fiber as shown in FIG. 5. The volume of the fiber 434 is filled by an alternating arrangement of first pie segment 440, and second pie segment 442. The alternating first pie segments 440 and second pie segments 442 extend along the length, or along the entire length, of the fiber 434, and are integral and inseparable.

[00123] In an embodiment, the fibers have a tip-core configuration. FIG. 6 shows a sectional view of a fiber 534 having a core 540. The core 540 is composed of component (1). The fiber 534 includes a plurality of tip portions 542. The tip portions 542 are composed of component (2). The core 540 and the tip portions 542 extend along the length, or along the entire length, of the fiber 534, and are integral and inseparable.

[00124] In an embodiment, the fibers have a segmented ribbon configuration. FIG. 7 shows a fiber 634 having a plurality of first ribbon segments 640. The first ribbon segments 640 are composed of component (1). The fiber 634 also includes a plurality of second ribbon segments 642. The second ribbon segments are composed of component (2). Each ribbon segment 640, 642 extends a first side of the fiber to an opposing side of the fiber as shown in FIG. 7. The volume of the fiber 634 is filled by an alternating arrangement of first ribbon segments 640 and second ribbon segments 642. The alternating first ribbon segments 440 and second ribbon segments 442 extend along the length, or along the entire length, of the fiber 634, and are integral and inseparable.

[00125] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following Examples.

EXAMPLES

[00126] A sheet of 3DRLM is composed of fibers having a core-sheath configuration as shown in FIG. 3. The core is composed of component (1) that is an ethylene-octene copolymer with a density of 0.917 g/cc sold under the tradename DOWLEX 2517, available from The Dow Chemical Company. The fibers include 90 vol % of the core. The sheath is composed of component (2) that is an ethylene/C₄-C₈ a-olefin copolymer that is a CDC45- ethylene copolymer and having a density from 0.86 g/cc to 0.89 g/cc. The fibers include 10 vol% of the sheath. The core-sheath fiber described in this paragraph is hereafter referred to as Fiberl.

[00127] The sheet of 3DRLM composed of Fiberl is an all-polyethylene sheet and exhibits bond strength of (1) an average maximum force (in newtons, N), from 110 Newtons (N) to 120N and an average yield force from 91 N to 100 N.

[00128] It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come with the scope of the following claims.

Claims

1. A sheet comprising:

a three-dimensional random loop material comprising a web structure of a multitude of winding continuous fibers melt-bonded together at a multitude of contact points to form a multitude of loops;

each continuous fiber comprising:

a component (1) that is an olefin-based polymer having a density from 0.86 g/cc to 0.96 g/cc;

a component (2) that is an olefin-based polymer having a density from 0.86 g/cc to 0.96 g/cc; and

the three-dimensional random loop material has an apparent density from 0.03 g/cc to 0.08 g/cc.

2. The sheet of claim 1 wherein the component (1) olefin-based polymer is an ethylene-based polymer having a density from 0.90 g/cc to 0.96 g/cc; and

the component (2) olefin-based polymer is an ethylene-based polymer having a density from 0.86 g/cc to 0.89 g/cc.

3. The sheet of any of claims 1-2 wherein component (1) has a first melt temperature, Tml, and component (2) has a second melt temperature, Tm2, wherein the difference between Tml and Tm2 is ΔΤιη; and

ΔΤιτι is from 0°C to 10°C.

4. The sheet of any of claims 1-3 wherein component (1) is selected from the group consisting of a linear low density polyethylene and a high density polyethylene (HDPE).

5. The sheet of any of claims 1-3 wherein component (1) is a propylene-based polymer.

6. The sheet of any claims 1-5 wherein component (2) is an ethylene/C₄-C₈ a-olefin copolymer having Comonomer Distribution Constant in the range of from greater than 45 to less than 400, wherein the composition has less than 120 total unsaturation unit/l,000,000C.

7. The sheet of any of claims 1-5 wherein component (2) is an ethylene/C₄-C₈ a-olefin multi-block copolymer.

8. The sheet of any of claims 1-5 wherein component (2) is a propylene-based plastomer or elastomer (PBPE).

9. The sheet of any of claims 1-8 wherein the fibers are in the form of a sheath-core bicomponent fiber, the core being component (1) and the sheath being component (2).

10. The sheet of claim 9 wherein each fiber comprises from 5 vol% to 50 vol% of the sheath and from 95 vol% to 50 vol% of the core based on the total volume of the fiber.

11. The sheet of claim 10 wherein component (1) of the core is an ethylene-based polymer and the component (2) of the sheath is an ethylene-based polymer.

12. The sheet of claim 11 wherein component (1) of the core is an ethylene/C₄-C₈ a- olefin copolymer having a density from 0.90 g/cc to 0.96 g/cc; and component (2) of the sheath is an ethylene/C₄-C₈ a-olefin copolymer having a density from 0.86 g/cc to 0.89 g/cc.

13. The sheet of claim 8 wherein an additive is blended into at least one of the olefin- based polymer component (1) and olefin-based polymer component (2).

14. The sheet of claim 13 wherein the additive is selected from the group consisting of stabilizer, processing aid, filler, coloring pigment, sound-blocking agent, crosslinking agent, foaming agent, flame retardant, UV inhibitor, antimicrobial agent, and combinations thereof.