Bicomponent fibers comprising ethylene / alpha-olefin interpolymer and polyester

Abstract

Provided are bicomponent fibers having improved curvature. The bicomponent fibers include a first polymer region or first region and a second polymer region or second region. The first region according to embodiments of the present disclosure comprises an ethylene / α-olefin interpolymer and has a light scattering cumulative detector fraction (CDF) greater than 0.1200. LS ), where the CDF LS The molecular weight of the bicomponent fibers is calculated by measuring the area fraction of the low angle laser light scattering (LALLS) detector chromatogram of the fibers having a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC). The second region comprises polyester. The bicomponent fibers can be used to form nonwovens.

Description

Technical Field

[0001] Embodiments of the present disclosure are generally directed to bicomponent fibers having curvature, the bicomponent fibers comprising an ethylene / α-olefin interpolymer and a polyester, and nonwovens comprising the fibers. Background Art

[0002] Bicomponent fiber is the fiber made of two different polymer compositions, and these two different polymer compositions are extruded from the same spinneret, wherein the same filament or fiber contains these two compositions.When this fiber leaves the spinneret, it is made up of the non-mixed components that melt at the interface.These two polymer compositions can be different in their chemical and / or physical properties.Bicomponent fiber can be formed by conventional spinning techniques known in the art, and can be used to form nonwoven fabric.Nonwoven fabric has multiple applications, such as disposable materials and diapers in filters, medical applications.In order to help reduce nonwoven weight or obtain other favorable nonwoven fabric properties, such as bulk (loft), bicomponent fiber with curvature can be used.However, there is the problem of obtaining bicomponent fiber with increased curvature and maintaining or improving other favorable properties, such as spinnability, stiffness and tensile strength when improving curvature. Summary of the Invention

[0003] Embodiments of the present disclosure provide bicomponent fibers that can be used to form nonwovens and provide unique and surprisingly high curvature in various aspects while also maintaining or improving other properties, such as spinnability, stiffness, and tensile strength. The bicomponent fibers according to embodiments of the present disclosure each include a first polymer region and a second polymer region, the first polymer region and the second polymer region respectively comprising a first polymer and a second polymer, the first polymer and the second polymer contributing to fibers with improved curvature. Specifically, the bicomponent fibers according to embodiments of the present disclosure include a first polymer region or a first region containing an ethylene / α-olefin interpolymer that can provide softness, and a second polymer region or a second region containing a polyester that can provide high tensile strength, stiffness, and spinnability. The improved curvature of the fibers disclosed herein is not the result of mechanical curling or post-extrusion processes (such as thinning with heated air or applying tension).

[0004] Disclosed herein is a bicomponent fiber. In an embodiment, the bicomponent fiber comprises a fiber centroid; a first region having a first centroid and a second region having a second centroid; the first region comprising an ethylene / α-olefin interpolymer in an amount of at least 50 weight percent based on the total weight of the first region and a low density polyethylene in an amount of 0 weight percent to 40 weight percent based on the total weight of the first region; the first region having a light scattering cumulative detector fraction (CDF) greater than 0.1200. LS), where the CDF LS is calculated by measuring the area fraction of a low angle laser light scattering (LALLS) detector chromatogram having a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC); the second region comprises polyester; and wherein at least one of the first centroid and the second centroid is different from the fiber centroid;

[0005] In another embodiment, a bicomponent fiber is disclosed wherein the fiber has a light scattering cumulative detector fraction (CDF) greater than 0.1600. LS ), where the CDF LS The molecular weight of the bicomponent fiber is calculated by measuring the area fraction of a low angle laser light scattering (LALLS) detector chromatogram greater than or equal to 1,000,000 g / mol molecular weight using gel permeation chromatography (GPC). In such embodiments, the bicomponent fiber comprises a fiber centroid; a first region having a first centroid and a second region having a second centroid; the first region comprising an ethylene / α-olefin interpolymer in an amount of at least 50 weight percent based on the total weight of the first region and a low density polyethylene in an amount of from 0 weight percent to 40 weight percent based on the total weight of the first region; the second region comprising a polyester; wherein at least one of the first centroid and the second centroid is different from the fiber centroid; and wherein the fiber has a light scattering cumulative detector fraction (CDF) greater than 0.1600. LS ), where the CDF LS It is calculated by measuring the area fraction of the low angle laser light scattering (LALLS) detector chromatogram with a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC).

[0006] Also disclosed herein is a nonwoven comprising bicomponent fibers. In an embodiment, the nonwoven comprises bicomponent fibers, wherein the bicomponent fibers comprise a fiber centroid; a first region having a first centroid and a second region having a second centroid; the first region comprising an ethylene / α-olefin interpolymer in an amount of at least 50 weight percent based on the total weight of the first region and a low density polyethylene in an amount of 0 weight percent to 40 weight percent based on the total weight of the first region; the first region having a light scattering cumulative detector fraction (CDF) greater than 0.1200. LS ), where the CDF LS is calculated by measuring the area fraction of a low angle laser light scattering (LALLS) detector chromatogram having a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC); the second region comprises polyester; and wherein at least one of the first centroid and the second centroid is different from the fiber centroid;

[0007] Additional features and advantages of the embodiments will be set forth in the detailed description that follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the following detailed description, claims, and drawings.

[0008] It should be understood that the foregoing and following descriptions describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments and are incorporated into and constitute a part of this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a scanning electron micrograph (SEM) cross-sectional image of an eccentric core-sheath bicomponent fiber.

[0010] Figure 2 is a schematic diagram of the reactor stream feed data flows corresponding to the development resin used in the examples. DETAILED DESCRIPTION

[0011] Various aspects of the disclosed bicomponent fibers are described in more detail below. Bicomponent fibers with increased curvature can be used to form nonwovens, and such nonwovens can have various applications. However, it should be noted that this is merely an illustrative implementation of the embodiments disclosed herein. These embodiments are applicable to other technologies susceptible to similar problems described above.

[0012] As used herein, the terms "comprising," "including," "having," and derivatives thereof are not intended to exclude the presence of any additional components, steps, or procedures, whether or not such components, steps, or procedures are specifically disclosed. For the avoidance of 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 subsequently recited component, step, or procedure any other component, step, or procedure, except those that are not essential to operability. The term "consisting of excludes any ingredient, step, or procedure not specifically recited or listed.

[0013] As used herein, the term "interpolymer" refers to polymers prepared by polymerizing at least two different types of monomers. The term interpolymer thus includes copolymers (used to refer to polymers prepared from two different types of monomers) and polymers prepared from more than two different types of monomers.

[0014] As used herein, the term "polymer" means a polymeric compound prepared by polymerizing monomers of the same or different type. The term polymer thus encompasses the term homopolymer (used to refer to a polymer prepared from only one type of monomer, it being understood that trace amounts of impurities may be incorporated into the polymer structure) and the term interpolymer, as defined below. Trace amounts of impurities (e.g., catalyst residues) may be incorporated into and / or within the polymer. The polymer may be a single polymer or a polymer blend.

[0015] As used herein, the term "polyolefin" refers to polymers that comprise, in polymerized form, major amounts of olefin monomers (eg, ethylene or propylene) based on the weight of the polymer, and optionally may contain one or more comonomers.

[0016] As used herein, the term "polyester" refers to a polymer produced by the reaction of a hydroxyl (-OH) containing material with a polycarboxylic acid or its anhydride or at least one carboxylic acid and at least one polyfunctional alcohol (e.g., a diol, triol, or other polyol), the reaction product of which thus has more than one ester group and which itself has an average of more than one hydroxyl group.

[0017] As used herein, the terms "nonwoven," "nonwoven web," and "nonwoven fabric" are used interchangeably herein. "Nonwoven" refers to a web or fabric having a structure of individual fibers or threads that are randomly interlaced rather than in an identifiable pattern as in a knitted fabric.

[0018] As used herein, the term "curvature" refers to the curvature or curl of an individual fiber that is a result of its composition and not the result of any post-extrusion processing (e.g., mechanical crimping or attenuation by heat) that may affect the curvature or curl of the fiber. The amount of curvature of the bicomponent fibers disclosed herein can be measured according to the test method described below.

[0019] As used herein, the term "spunbond" refers to the manufacture of nonwoven fabrics comprising the steps of: (a) extruding molten thermoplastic strands from a plurality of fine capillaries called spinnerets; (b) quenching the strands with a stream of air that is typically cooled to accelerate the solidification of the molten strands; (c) drawing the strands by propelling them through a quenching zone with a tensile tension that can be applied by pneumatically entraining the strands in an air stream or by wrapping the strands around mechanical stretching rollers of the type commonly used in the textile fiber industry; (d) collecting the stretched strands into a web on a small-forged surface, such as a moving screen or porous belt; and (e) bonding the web of loose strands into a nonwoven fabric. Bonding can be achieved in a variety of ways, including but not limited to thermal calendering processes, adhesive bonding processes, hot air bonding processes, needle punching processes, hydroentanglement processes, and combinations thereof.

[0020] As used herein, the term "meltblown" refers to a nonwoven fabric made by a process generally comprising the following steps: (a) extruding molten thermoplastic strands from a spinneret; (b) simultaneously quenching and attenuating the polymer stream just below the spinneret using a high velocity heated air stream; and (c) collecting the stretched strands into a web on a collecting surface. The meltblown web can be bonded by various means, including but not limited to autogenous bonding (i.e., self-bonding without further treatment), thermal calendering processes, adhesive bonding processes, hot air bonding processes, needlepunching processes, hydroentanglement processes, and combinations thereof.

[0021] fiber

[0022] The bicomponent fiber according to the embodiment of the present disclosure can be formed into fiber via different technologies (for example, via melt spinning).In melt spinning, the first region and the second region can be melted, coextruded and forced to pass through the fine orifice mouth in the metal plate, spinneret, enter air or other gases, wherein the coextruded region is cooled and solidified to form the bicomponent fiber.The solidified filament can be extracted via air nozzle, rotating roller or godet, and can be laid on a conveyor belt as a net to form a nonwoven.The nonwoven comprising the bicomponent fiber disclosed herein can be formed via different technologies.For example, in one embodiment, a spunbond nonwoven comprising bicomponent fiber disclosed herein can be formed.In other embodiments, a meltblown nonwoven comprising bicomponent fiber disclosed herein can be formed.

[0023] The bicomponent fibers disclosed herein have improved curvature. In the embodiments described herein, the bicomponent fibers have a curvature of at least 1.10 mm. -1 The curvature of the bicomponent fibers may be measured according to the test method described below. The curvature of the bicomponent fibers disclosed herein and including fibers having a curvature of at least 1.10 mm -1 For example, in some embodiments, the curvature of the bicomponent fiber can be at least 1.20 mm when measured according to the test method described below. -1 , 1.30mm -1 , 1.40mm -1 or 1.50mm -1 In other embodiments, the curvature of the bicomponent fiber may be between 1.10 mm and 2.10 mm when measured according to the test method described below. -1 Up to 6.00mm -1 , 1.10mm -1 Up to 5.00mm -1 , 1.10mm -1 Up to 4.00mm -1 , 1.10mm -1 Up to 3.00mm -1 , 1.10mm -1 Up to 2.00mm-1 , 1.10mm -1 Up to 1.90mm -1 , 1.20mm -1 Up to 6.00mm -1 , 1.20mm -1 Up to 5.00mm -1 , 1.20mm -1 Up to 4.00mm -1 , 1.20mm -1 Up to 3.00mm -1 , 1.20mm -1 Up to 2.00mm -1 , 1.30mm -1 Up to 6.00mm -1 , 1.30mm -1 Up to 5.00mm -1 , 1.30mm -1 Up to 4.00mm -1 , 1.30mm -1 Up to 3.00mm -1 , 1.30mm -1 Up to 2.00mm -1 , 1.40mm -1 Up to 6.00mm -1 , 1.40mm -1 Up to 5.00mm -1 , 1.40mm -1 Up to 4.00mm -1 , 1.40mm -1 Up to 3.00mm -1 , 1.40mm -1 Up to 2.00mm -1 , 1.50mm -1 Up to 6.00mm -1 , 1.50mm -1 Up to 5.00mm -1 , 1.50mm -1 Up to 4.00mm -1 , 1.50mm -1 Up to 3.00mm -1 , or 1.50mm -1 Up to 2.00mm -1 within the range.

[0024] In an embodiment, the bicomponent fiber comprises a first region and a second region, wherein the weight ratio of the first region to the second region is from 90:10 to 10:90. All individual values ​​and subranges of the ratio from 90:10 to 10:90 are disclosed and included herein. For example, in an embodiment, the weight ratio of the first region to the second region is from 90:10 to 10:90, from 80:20 to 20:80, from 70:30 to 30:70, from 60:40 to 40:60, or from 55:45 to 45:55.

[0025] In embodiments, the bicomponent fiber has a light scattering cumulative detector fraction (CDF) greater than 0.1500. LS ), where the CDF LS It is calculated by measuring the area fraction of the low angle laser light scattering (LALLS) detector chromatogram of molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC). LS For example, in some embodiments, a bicomponent fiber may have a CDF greater than 0.1600, greater than 0.2000, greater than 0.2200, greater than 0.2400, or greater than 0.2600. LS , where the CDF LS The CDF is calculated by measuring the area fraction of a low angle laser light scattering (LALLS) detector chromatogram having a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC). In other embodiments, the bicomponent fiber may have a CDF in the range of 0.1500 to 0.5000, 0.1600 to 0.5000, 0.2000 to 0.5000, 0.2500 to 0.5000, 0.3000 to 0.5000, 0.1600 to 0.4500, 0.2000 to 0.4500, 0.2500 to 0.4500, 0.3000 to 0.4500, 0.2000 to 0.4000, 0.2500 to 0.4000, 0.2000 to 0.3500, or 0.2500 to 0.3500. LS , where the CDF LS It is calculated by measuring the area fraction of the low angle laser light scattering (LALLS) detector chromatogram with a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC).

[0026] In embodiments, the bicomponent fiber has an infrared cumulative detector fraction (CDF) greater than 0.0100. IR ), where the CDF IRIt is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram with a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC). The CDF greater than 0.0100 is disclosed and included herein. IR For example, in some embodiments, a bicomponent fiber may have a CDF greater than 0.0150, greater than 0.0200, or greater than 0.0225. IR , where the CDF IR It is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram with a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC). In other embodiments, the bicomponent fiber may have a molecular weight between 0.0100 and 0.1500, 0.0100 and 0.1300, 0.0100 and 0.1100, 0.0100 and 0.0900, 0.0100 and 0.0700, 0.0100 and 0.0500, 0.0100 and 0.0400, 0.0200 and 0.1500, 0.0200 and 0.1300, 0.0200 and 0.1100, 0.0200 and 0.0500. CDF in the range of 0.200 to 0.0900, 0.0200 to 0.0700, 0.0200 to 0.0500, 0.0200 to 0.0300, 0.0300 to 0.1500, 0.0300 to 0.1300, 0.0300 to 0.1100, 0.0300 to 0.0900, 0.0300 to 0.0700, 0.0300 to 0.0500, or 0.0300 to 0.0400 IR , where the CDF IR It is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram having a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC).

[0027] Center of mass

[0028] In an embodiment, a bicomponent fiber comprises a fiber centroid and a first region having a first centroid and a second region having a second centroid, wherein at least one of the first centroid and the second centroid is different than the fiber centroid.

[0029] As used herein, the term "centroid" refers to the arithmetic mean of all points of the cross-sectional area of ​​a bicomponent fiber. For example, a bicomponent fiber according to an embodiment of the present disclosure has a fiber centroid, which can be designated as C f , and a region of the bicomponent fiber (e.g., the first or second region) has an independent centroid, which can be designated as C rx , where x is the name of the region (for example, the first region may be designated as Cr1 , and the second region can be designated as C r2 ), and where "r" is from C f The average distance to the outer surface of the bicomponent fiber is calculated as where A is the area of ​​the bicomponent fiber cross section. Figure 1 The bicomponent fiber and its centroid and the centroid of a second region of the bicomponent fiber are shown. The distance from the region centroid to the fiber centroid can be defined as "P rx ”, and the centroid offset of the first centroid or the second centroid from the fiber centroid can be defined as “P rx / r”.

[0030] In an embodiment, at least one of the first center of mass and the second center of mass is different from the fiber center of mass. In the case where the first center of mass or the second center of mass is different from the fiber center of mass, the bicomponent fiber can have different configurations, such as eccentric core-sheath or side by side, but cannot have a concentric configuration (e.g., a core-sheath concentric configuration) in which the fiber center of mass, the first center of mass and the second center of mass are the same. In an embodiment, the first center of mass of the first region and the second center of mass of the second region are arranged so that the first region and the second region are in a side by side configuration. In other embodiments, the first center of mass of the first region and the second center of mass of the second region are arranged so that the first region and the second region are in a split pie configuration. In another embodiment, the first center of mass of the first region and the second center of mass of the second region are arranged so that the first region and the second region are in an eccentric core-sheath configuration, wherein the first region is the sheath of the bicomponent fiber and the second region is the core region of the bicomponent fiber, and the sheath region surrounds the core region.

[0031] In embodiments, the first center of mass or the second center of mass is positioned at least 0.1, or at least 0.2, or at least 0.4, and less than 1, or less than 0.9, from the fiber center of mass, wherein the offset is measured according to the test method described below.

[0032] First region and ethylene / α-olefin interpolymer

[0033] In an embodiment, the first region of the bicomponent fiber comprises the ethylene / α-olefin interpolymer in an amount of at least 50 weight percent (wt%), based on the total weight of the first region.

[0034] The term "ethylene / α-olefin interpolymer" generally refers to a polymer comprising ethylene and an α-olefin having 3 or more carbon atoms. The ethylene / α-olefin interpolymer of the first region comprises greater than 70 weight percent units derived from ethylene and less than 30 weight percent units derived from one or more α-olefin comonomers (based on the total amount of polymerizable monomers). All individual values ​​and subranges for greater than 70 weight percent units derived from ethylene and less than 30 weight percent units derived from one or more α-olefin comonomers are included herein and disclosed. For example, in one or more embodiments, either or both of the ethylene / α-olefin interpolymers may comprise (a) greater than, or equal to, 75%, greater than, or equal to, 80%, greater than, or equal to, 85%, greater than, or equal to, 90%, greater than, or equal to, 92%, greater than, or equal to, 95%, greater than, or equal to, 97%, greater than, or equal to, 98%, greater than, or equal to, 99%, greater than, or equal to, 99.5%, from greater than 70% to 99%, from greater than 70% to 97%, from greater than 70% to 94%, from greater than 70% to 90%, from 70% to 99.5 ... 0% to 99%, from 70% to 97%, from 70% to 94%, from 80% to 99.5%, from 80% to 99%, from 80% to 97%, from 80% to 94%, from 80% to 90%, from 85% to 99.5%, from 85% to 99%, from 85% to 97%, from 88% to 99.9%, 88% to 99.7%, from 88% to 99.5%, from 88% to 99%, from 88% to 98%, from 88% to 97%, from 88% to 95%, from 88% to 94%, from 90% to 99.9%, from 90% to % to 99%, from 90% to 97%, from 90% to 95%, from 93% to 99.9%, from 93% to 99.5%, from 93% to 99%, or from 93% to 97% of units derived from ethylene; and (b) by weight, less than 30%, for example, less than 25%, or less than 20%, less than 18%, less than 15%, less than 12%, less than 10%, less than 8%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, from 0.1 to 20%, from 0.1 to 15%, 0.1 to 12%, % to 7%, or 4 to 12%, 4 to 10%, 4 to 8%, or 4 to 7% of units derived from one or more α-olefin comonomers.Comonomer content can be measured using any suitable technique, such as techniques based on nuclear magnetic resonance ("NMR") spectroscopy, and for example, as described in US Patent 7,498,282. 13 C NMR analysis, which is incorporated herein by reference.

[0035] Suitable α-olefin comonomers typically have no more than 20 carbon atoms. One or more α-olefins can be selected from the group consisting of: C3-C20 acetylenically unsaturated monomers and C4-C18 dienes. 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, for example, be selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene; or, in the alternative, from the group consisting of 1-butene, 1-hexene, and 1-octene; or, in the alternative, from the group consisting of 1-hexene and 1-octene. In one or more embodiments, each ethylene / α-olefin interpolymer can comprise greater than 0 wt% and less than 30 wt% of units derived from one or more of 1-octene, 1-hexene, or 1-butene comonomers.

[0036] As described above, the first region comprises an ethylene / α-olefin interpolymer in an amount of at least 50 wt %, based on the total weight of the first region. All individual values ​​and subranges of at least 50 weight percent (wt %), based on the total weight of the first region, are included and disclosed herein. For example, in one or more embodiments, the first region comprises an ethylene / α-olefin interpolymer in an amount of at least 50 wt %, at least 60 wt %, at least 70 wt %, at least 75 wt %, at least 80 wt %, at least 90 wt %, at least 95 wt %, at least 99 wt %, at least 99.5 wt %, or at least 99.9 wt %, based on the total weight of the first region. In other embodiments, the first region comprises the ethylene / α-olefin interpolymer in amounts of 50 wt% to 60 wt%, 50 wt% to 70 wt%, 50 wt% to 80 wt%, 50 wt% to 90 wt%, 50 wt% to 99 wt%, 50 wt% to 100 wt%, 60 wt% to 70 wt%, 60 wt% to 80 wt%, 60 wt% to 90 wt%, 60 wt% to 99 wt%, 60 wt% to 100 wt%, 70 wt% to 80 wt%, 70 wt% to 90 wt%, 70 wt% to 99 wt%, 70 wt% to 100 wt%, 80 wt% to 90 wt%, 80 wt% to 99 wt%, 90 wt% to 99 wt%, and 90 wt% to 100 wt%, based on the total weight of the first region of the bicomponent fiber.

[0037] In an embodiment, the ethylene / α-olefin interpolymer has a density between 0.910 g / cm 3 to 0.964g / cm 3 The present invention discloses and includes 0.910g / cm 3 to 0.964g / cm 3 All individual values ​​and subranges of density within the range of . For example, in some embodiments, the density of the ethylene / α-olefin interpolymer may be between 0.910 g / cm 3 to 0.964g / cm 3 、0.910g / cm 3 to 0.960g / cm 3 , 0.920g / cm 3 to 0.960g / cm 3 、0.930g / cm 3 to 0.960g / cm 3 、0.940g / cm 3 to 0.960g / cm 3 、0.950g / cm 3 to 0.960g / cm 3 、0.910g / cm 3 to 0.950g / cm 3 、0.920g / cm 3 to 0.950g / cm 3 、0.930g / cm 3 to 0.950g / cm 3 、0.940g / cm 3 to 0.950g / cm 3 、0.910g / cm 3 to 0.940g / cm 3 、0.920g / cm 3 to 0.940g / cm 3 、0.930g / cm 3 to 0.940g / cm 3 、0.910g / cm 3 to 0.930g / cm 3 、0.920g / cm 3 to 0.930g / cm 3 , or 0.910g / cm 3 to 0.920g / cm 3 The density can be measured according to ASTM D792.

[0038] In an embodiment, the ethylene / α-olefin interpolymer has a melt index (I2) in the range of 10 g / 10 min to 60 g / 10 min, as measured according to ASTM D1238, 190° C., 2.16 kg. All individual values ​​and subranges from 10 g / 10 min to 60 g / 10 min are included and disclosed herein. For example, in some embodiments, the ethylene / α-olefin interpolymer may have a melt index (I2) in the range of 10 g / 10 min to 60 g / 10 min, 10 g / 10 min to 50 g / 10 min, 10 g / 10 min to 40 g / 10 min, 10 g / 10 min to 30 g / 10 min, 10 g / 10 min to 20 g / 10 min, 20 g / 10 min to 60 g / 10 min, 20 g / 10 min to 30 g / 10 min, The melt index (I2) may be measured according to ASTM D1238, 190°C, 2.16 kg.

[0039] In an embodiment, the ethylene / α-olefin interpolymer has a ratio of weight average molecular weight to number average molecular weight (M) greater than 3.0. w(GPC) / M n(GPC) ) molecular weight distribution. Disclosed herein and including molecular weight distribution (M) greater than 3.0 w(GPC) / M n(GPC) ) all individual values ​​and subranges; for example, in embodiments, the molecular weight distribution (M w(GPC) / M n(GPC) ) is greater than 3.0, greater than 3.02, greater than 3.04, greater than 3.06, greater than 3.08, greater than 3.10, greater than 3.12, or greater than 3.14, or in the range of 3.0 to 5.0, 3.0 to 4.5, 3.0 to 4.0, 3.0 to 3.5, 3.0 to 3.2, 3.1 to 5.0, 3.1 to 4.5, 3.1 to 4.0, 3.1 to 3.5, or 3.1 to 3.2, wherein the molecular weight distribution can be expressed as the ratio of weight average molecular weight to number average molecular weight (M w(GPC) / M n(GPC) ).

[0040] In an embodiment, the first region has a molecular weight expressed as a ratio of weight average molecular weight to number average molecular weight (M w(GPC) / M n(GPC)) molecular weight distribution. Disclosed herein and including molecular weight distribution (M) greater than 3.35 w(GPC) / M n(GPC) ) all individual values ​​and subranges; for example, in embodiments, the molecular weight distribution of the first region (M w(GPC) / M n(GPC) ) is greater than 3.35, or greater than 3.50, greater than 3.75, greater than 4.00, greater than 4.25, greater than 4.50, greater than 4.75, or greater than 4.90, or in the range of 3.35 to 6.00, 3.35 to 5.50, or 3.35 to 5.00, wherein the molecular weight distribution can be expressed as the ratio of weight average molecular weight to number average molecular weight (M w(GPC) / M n(GPC) ).

[0041] In embodiments, the first region of bicomponent fiber further comprises the Low Density Polyethylene (LDPE) that the gross weight based on the first region is 0 % by weight to 40 % by weight.Disclosed herein and include all independent values ​​and subranges of 0 weight percent (% by weight) to 40 % by weight; For example, in embodiments, the first region comprises the Low Density Polyethylene (LDPE) that the gross weight based on the first region is 0 % by weight to 40 % by weight, 0 % by weight to 30 % by weight, 0 % by weight to 20 % by weight, 0 % by weight to 10 % by weight, 10 % by weight to 40 % by weight, 10 % by weight to 30 % by weight, 10 % by weight to 20 % by weight, 15 % by weight to 40 % by weight, 15 % by weight to 30 % by weight, 15 % by weight to 25 % by weight, 20 % by weight to 40 % by weight, 20 % by weight to 30 % by weight or 30 % by weight to 40 % by weight.

[0042] In an embodiment, the first region may comprise additional components such as one or more other polymers, polymer blends, and / or one or more additives. The other polymers or polymer blends may include another polyethylene (e.g., a polyethylene homopolymer or an ethylene / α-olefin interpolymer), a polyester, a propylene-based polymer (e.g., a polypropylene homopolymer, a propylene-ethylene copolymer, or a propylene / α-olefin interpolymer), or a propylene-based plastomer or elastomer. The amount of the other polymers or other polymer blends may be up to 50 wt % based on the total weight of the first region. For example, in an embodiment, the first region may comprise up to 50 wt % of a propylene-based plastomer or a propylene-based elastomer (such as VERSIFY® available from The Dow Chemical Company). TM Polymers and VISTAMAXX available from ExxonMobil Chemical Co. TM Polymers), low modulus and / or low molecular weight polypropylene (such as L-MODU from Idemitsu) TMPolymers), random copolymers of polypropylene, or propylene-based olefin block copolymers (such as Intune). Potential additives include, but are not limited to, antistatic agents, colorants, dyes, lubricants, fillers, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, antiblocking agents, slip agents, tackifiers, flame retardants, antimicrobials, deodorants, antifungals, and combinations thereof. Based on the weight of the first region containing such additives, the first region may contain from about 0.01 wt % or 0.1 wt % or 1 wt % to about 25 wt % or about 20 wt % or about 15 wt % or about 10 wt % of such additives by combined weight.

[0043] In an embodiment, the first region may further include a polyolefin elastomer. For example, a polyolefin elastomer may be provided to increase the extensibility of the nonwoven fabric formed by the bicomponent fibers described herein. In some embodiments, the polyolefin elastomer may be a block copolymer. In some embodiments in which a polyolefin elastomer is used in the first region, the first region may include 50 weight percent (wt%) or less of the polyolefin elastomer based on the gross weight of the first region. Examples of commercially available polyolefin elastomers that can be used in some embodiments of the present invention include those available under the trade name VERSIFY TM ENGAGE TM 、AFFINITY TM and INFUSE TM Polyolefin elastomers available from The Dow Chemical Company under the trade name VISTAMAXX TM Polyolefin elastomers available from ExxonMobil Chemical Company and also available under the trade name L-MODU TM Polyolefin elastomer purchased from Idemitsu Lubricants Co., Ltd.

[0044] In embodiments, the first region has a light scattering cumulative detector fraction (CDF) greater than 0.1200. LS ), where the CDF LS It is calculated by measuring the area fraction of the low angle laser light scattering (LALLS) detector chromatogram of molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC). LS For example, in some embodiments, the first region has a CDF greater than 0.1200, greater than 0.1400, greater than 0.1600, greater than 0.1800, greater than 0.2000, greater than 0.2200, greater than 0.2400, greater than 0.2600, greater than 0.2800, or greater than 0.3000.LS , where the CDF LS It is calculated by measuring the area fraction of the low angle laser light scattering (LALLS) detector chromatogram with a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC). In other embodiments, the first region can have a CDF in the range of 0.1200 to 0.5000, 0.1500 to 0.5000, 0.2000 to 0.5000, 0.2500 to 0.5000, 0.3000 to 0.5000, 0.1200 to 0.4500, 0.1500 to 0.4500, 0.2000 to 0.4500, 0.2500 to 0.4500, 0.3000 to 0.4500, 0.2000 to 0.4000, 0.2500 to 0.4000, 0.3000 to 0.4000, 0.2000 to 0.3500, 0.2500 to 0.3500, or 0.3000 to 0.3500. LS , where the CDF LS It is calculated by measuring the area fraction of the low angle laser light scattering (LALLS) detector chromatogram with a molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC).

[0045] In an embodiment, the first region has an infrared cumulative detector fraction (CDF) greater than 0.0100. IR ), where the CDF IR It is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram with a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC). The CDF greater than 0.0100 is disclosed and included herein. IR For example, in some embodiments, the first region may have a CDF greater than 0.0150, greater than 0.0200, or greater than 0.0250. IR , where the CDF IRIt is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram having a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC). In other embodiments, the first region can have a CDF in the range of 0.0100 to 0.0500, 0.0100 to 0.0450, 0.0100 to 0.0400, 0.0100 to 0.0375, 0.0150 to 0.0500, 0.0150 to 0.0450, 0.0150 to 0.0400, 0.0150 to 0.0375, 0.0200 to 0.0500, 0.0200 to 0.0450, 0.0200 to 0.0400, 0.0200 to 0.0375, 0.0250 to 0.0500, 0.0250 to 0.0450, 0.0250 to 0.0400, 0.0250 to 0.0375 IR , where the CDF IR It is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram having a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC).

[0046] In embodiments, the first region has an Mw(Abs) / Mw(GPC) greater than 1.2, when calculated according to the Test Methods described below. All individual values ​​and subranges greater than 1.2 are disclosed and included herein; for example, the first region may have an Mw(Abs) / Mw(GPC) greater than 1.2, greater than 1.4, greater than 1.6, or greater than 1.8, or an Mw(Abs) / Mw(GPC) of 1.2 to 2.0, 1.4 to 2.0, 1.6 to 2.0, or 1.8 to 2.0, when calculated according to the Test Methods described below.

[0047] In embodiments, the first region has a gpcBR greater than 0.20, when measured according to the Test Method described below. All individual values ​​and subranges greater than 0.20 are disclosed and included herein; for example, the first region may have a gpcBR greater than 0.20, greater than 0.40, greater than 0.60, greater than 0.80, greater than 1.0, or greater than 1.1, or a gpcBR in the range of 0.2 to 2.0, 0.4 to 2.0, 0.6 to 2.0, 0.8 to 2.0, or 1.0 to 2.0, when measured according to the Test Method described below.

[0048] The ethylene / α-olefin interpolymers can be produced, for example, via a solution phase polymerization process using one or more loop reactors, isothermal reactors, continuous stirred tank reactors, and combinations thereof.

[0049] Typically, the solution phase polymerization process occurs in one or more well-stirred reactors (such as one or more loop reactors) at a temperature in the range of 115° C. to 250° C., for example, 155° C. to 225° C., and at a pressure in the range of 300 psi to 1000 psi, for example, 400 psi to 750 psi. In one embodiment, in a dual reactor, the temperature in the first reactor is in the range of 115° C. to 190° C. (for example, 115° C. to 150° C.), and the second reactor temperature is in the range of 150° C. to 200° C. (for example, 170° C. to 195° C.). In another embodiment, in a single reactor, the temperature in the reactor temperature is in the range of 115° C. to 250° C. (for example, 155° C. to 225° C.). The residence time in the solution phase polymerization process is typically in the range of 2 minutes to 30 minutes, for example, 10 minutes to 20 minutes. Ethylene, solvent, one or more catalyst systems, optionally one or more cocatalysts, optionally one or more impurity scavengers, and optionally one or more comonomers are continuously fed to the one or more reactors. Exemplary solvents include, but are not limited to, isoparaffins. For example, such solvents are available commercially as ISOPAR E from ExxonMobil Chemical Company in Houston, Texas. The resulting mixture of ethylene / α-olefin interpolymer and solvent is then removed from the reactor and the ethylene / α-olefin interpolymer is isolated. The solvent is typically recovered via a solvent recovery unit (i.e., a heat exchanger and a vapor liquid separator drum) and subsequently recycled back into the polymerization system.

[0050] In one embodiment, the ethylene / α-olefin interpolymer can be produced via a solution polymerization process in a dual reactor system (e.g., a dual loop reactor system) wherein ethylene and optionally one or more α-olefins are polymerized in the presence of one or more catalyst systems. Additionally, one or more cocatalysts may be present. In another embodiment, the ethylene / α-olefin interpolymer composition can be produced via a solution polymerization process in a single reactor system (e.g., a loop reactor system) wherein ethylene and optionally one or more α-olefins are polymerized in the presence of one or more catalyst systems. Additionally, one or more cocatalysts may be present.

[0051] Second region and polyester

[0052] The bicomponent fiber includes a second region. The second region comprises polyester.

[0053] In an embodiment, the second region comprises a polyester selected from the group consisting of polyethylene terephthalate, glycol-modified polyethylene terephthalate, polybutylene terephthalate, and combinations thereof. In an embodiment, the density of the polyester is between 1.2 g / cm 3 Up to 1.5g / cm 3This article includes and discloses 1.2g / cm 3 Up to 1.5g / cm 3 All values ​​and subranges of density within the range; for example: in some embodiments, the density of polyester is 1.2 g / cm 3 Up to 1.5g / cm 3 , 1.25g / cm 3 Up to 1.5g / cm 3 , 1.3g / cm 3 Up to 1.5g / cm 3 , 1.35g / cm 3 Up to 1.5g / cm 3 , 1.2g / cm 3 Up to 1.45g / cm 3 , 1.25g / cm 3 Up to 1.45g / cm 3 , 1.3g / cm 3 Up to 1.45g / cm 3 , or 1.35g / cm 3 Up to 1.45g / cm 3 In an embodiment, the polyester has a molecular weight equivalent to an intrinsic viscosity (IV) of 0.5 to 1.4 (dl / g), wherein IV is determined according to ASTM D4603 or 2857.

[0054] In an embodiment, the second region comprises polyester in an amount of at least 75 wt %, based on the total weight of the second region. All individual values ​​and subranges of at least 75 weight percent (wt %), based on the total weight of the second region, are included and disclosed herein. For example, in one or more embodiments, the second region comprises polyester in an amount of at least 75 wt %, at least 80 wt %, at least 90 wt %, at least 95 wt %, at least 99 wt %, at least 99.5 wt %, or at least 99.9 wt %, based on the total weight of the second region. In other embodiments, the second region comprises polyester in an amount of 75 wt % to 80 wt %, 75 wt % to 90 wt %, 75 wt % to 99 wt %, 75 wt % to 100 wt %, 80 wt % to 90 wt %, 80 wt % to 99 wt %, 90 wt % to 99 wt %, and 90 wt % to 100 wt %, based on the total weight of the second region of the bicomponent fiber.

[0055] In an embodiment, where the second region comprises polyester in an amount less than 100 wt %, the second region may comprise additional components such as one or more other polymers, polymer blends, and / or one or more additives or modifiers. The other polymer or polymer blend may include another polyester, a polyethylene (e.g., a polyethylene homopolymer or an ethylene / α-olefin interpolymer), a propylene-based polymer (e.g., a polypropylene homopolymer, a propylene-ethylene copolymer, or a propylene / α-olefin interpolymer), or a propylene-based plastomer or elastomer. The amount of the other polymer or other polymer blend may be up to 25 wt %, based on the total weight of the second region. For example, in an embodiment, the second region may comprise up to 25 wt % of a propylene-based plastomer or a propylene-based elastomer (such as VERSIFY® available from The Dow Chemical Company). TM polymers and VISTAMAXX available from ExxonMobil Chemical Company TM Polymers), low modulus and / or low molecular weight polypropylene (such as L-MODU from Idemitsu TM Polymers), random copolymers, or propylene-based olefin block copolymers (such as Intune). Potential additives include, but are not limited to, antistatic agents, colorants, dyes, lubricants, fillers, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, antiblocking agents, slip agents, tackifiers, flame retardants, antimicrobials, deodorants, antifungals, and combinations thereof. Potential modifiers include, but are not limited to, dicarbonic acid units and diol units. Examples of dicarbonic acid units are residues of isophthalic acid or aliphatic dicarbonic acids (e.g., glutaric acid, adipic acid, or sebacic acid); and examples of diol residues having a modifying effect are those of longer chain diols (e.g., propylene glycol or butanediol), those of diethylene glycol or triethylene glycol, or (if available in small quantities) those of polyethylene glycol having a molecular weight of 500 g / mol to 2000 g / mol. The second region may contain from about 0.01 wt % or 0.1 wt % or 1 wt % to about 25 wt % or about 20 wt % or about 15 wt % or about 10 wt % of such additives and / or modifiers by combined weight, based on the weight of the second region comprising such additives and / or modifiers.

[0056] Test Method

[0057] density

[0058] Density is measured according to ASTM D-792 and is expressed in grams per cm 3 (g / cm 3 )express.

[0059] Melt index (I2)

[0060] Melt index (I2) can be measured according to ASTM D 1238 at 190 degrees Celsius and 2.16 kg, and is expressed in grams eluted per 10 minutes (g / 10 min).

[0061] GPC

[0062] Triple detector gel permeation chromatography ( TDGPC )

[0063] The chromatography system consisted of a PolymerChar GPC-IR (Valencia, Spain) high temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR5) coupled to a Precision Detectors (now Agilent Technologies) 2-angle laser light scattering (LS) detector model 2040 and 4 capillary viscometers (DV). For all light scattering measurements, a 15-degree angle was used for measurement purposes. The autosampler oven chamber was set to 160 degrees Celsius, and the column chamber was set to 150 degrees Celsius. The columns used were four Agilent "Mixed A" 30 cm 20-micron linear mixed bed columns and a 20 μm precolumn. The chromatographic solvent used was 1,2,4 trichlorobenzene containing 200 ppm of butylated hydroxytoluene (BHT). The solvent source was nitrogen sparged. The injection volume used was 200 microliters, and the flow rate was 1.0 ml / min.

[0064] Calibration and calculation of conventional molecular weight moments and distributions were performed according to the methods described in the conventional GPC procedures (using a 20 μm "Mixed A" column).

[0065] The systematic method for determining the multi-detector offset was performed in a manner consistent with that published by Balke, Mourey et al. (Mourey and Balke, Chromatography Polym., Chapter 12, (1992)) (Balke, Thitiratsakul, Lew, Cheung, Mourey, Chromatography Polym., Chapter 13, (1992)) using the PolymerChar GPCOne TM The software optimizes the triple detector log (MW and IV) results from broad homopolymer polyethylene standards (Mw / Mn>3) with the narrow standards column calibration results from the narrow standards calibration curve.As used herein, "MW" refers to molecular weight.

[0066] Absolute molecular weight data were obtained using PolymerChar GPCOne TMThe software was developed in a manner consistent with that published by Zimm (Zimm, BH, Journal of Physical Chemistry, 16, 1099 (1948)) and Kratochvil (Kratochvil, P., Classical Light Scattering from Polymer Solutions, Elsevier, Oxford, NY (1987)). The total injected concentration used to determine the molecular weight was obtained from the mass detector area and the mass detector constant, which was derived from a suitable linear polyethylene homopolymer or one of the polyethylene standards of known weight average molecular weight. The calculated molecular weight (using GPCOne TM ) are obtained using the light scattering constants from one or more polyethylene standards mentioned below and a refractive index concentration coefficient dn / dc of 0.104. Typically, the mass detector response (IR5) and the light scattering constant (using GPCOne TM Viscometer calibration (using GPCOne TM The viscometer constant (measured using GPCOne) can be calculated using the method described by the manufacturer, or alternatively, by using the published value of a suitable linear standard such as Standard Reference Material (SRM) 1475a (available from the National Institute of Standards and Technology, NIST). TM Obtained), which relates the specific viscosity area (DV) and injected mass used for the calibration standard to its intrinsic viscosity (IV). The chromatographic concentration was assumed to be low enough to eliminate the effect of resolving the second viral coefficient (the effect of concentration on molecular weight).

[0067] The absolute weight average molecular weight (Mw(Abs)) is calculated by dividing the light scattering (LS) integrated chromatogram (determined by the light scattering constant) by the mass recovered from the mass constant and mass detector (IR5) area (using GPCOne TM The molecular weight and intrinsic viscosity responses were extrapolated at the end of the chromatogram where the signal-to-noise ratio was low (using GPCOne TM ). Other corresponding moments Mn (Abs) and Mz (Abs) The calculation according to equation 1-2 is as follows:

[0068]

[0069]

[0070] Conventional GPC

[0071] The chromatography system consisted of a PolymerChar GPC-IR (Valencia, Spain) high temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR5) coupled to a Precision Detector (now Agilent Technologies) 2-angle laser scattering (LS) detector model 2040. For all light scattering measurements, a 15-degree angle was used for measurement purposes. The autosampler oven chamber was set to 160 degrees Celsius, and the column chamber was set to 150 degrees Celsius. The columns used were four Agilent "MixedA" 30 cm 20-micron linear mixed bed columns. The chromatographic solvent used was 1,2,4 trichlorobenzene containing 200 ppm of butylated hydroxytoluene (BHT). The solvent source was nitrogen sparged. The injection volume used was 200 microliters, and the flow rate was 1.0 ml / min.

[0072] Calibration of the GPC column set was performed using 21 narrow molecular weight distribution polystyrene standards with molecular weights ranging from 580 g / mol to 8,400,000 g / mol and arranged in a cocktail mixture of six, with individual molecular weights separated by at least tenfold. Standards were purchased from Agilent Technologies. For molecular weights equal to or greater than 1,000,000 g / mol, polystyrene standards were prepared at 0.025 g in 50 ml of solvent, and for molecular weights less than 1,000,000 g / mol, polystyrene standards were prepared at 0.05 g in 50 ml of solvent. The polystyrene standards were dissolved at 80 degrees Celsius and gently stirred for 30 minutes. Polystyrene standard peak molecular weights were converted to polyethylene molecular weights using Equation 1 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)):

[0073] MW 聚乙烯 =A×(Mw 聚苯乙烯 ) B (Equation 3)

[0074] Where MW is the molecular weight, the value of A is 0.4315 and B is equal to 1.0.

[0075] A fifth-order polynomial was used to fit the calibration points of the corresponding polyethylene equivalents. A small adjustment (approximately 0.3950 to 0.440) was made to A to correct for column resolution and band broadening effects so that a linear homopolymer polyethylene standard was obtained at 120,000 Mw. The total plate count for the GPC column set was performed with decane (prepared with 0.04 g in 50 ml of TCB). Plate count (Equation 4) and symmetry (Equation 5) were measured at 200 microliter injections according to the following equations:

[0076]

[0077] where RV is the retention volume in milliliters, peak width is in milliliters, peak maximum is the maximum height of the peak, and 1 / 2 height is the height of 1 / 2 the peak maximum.

[0078]

[0079] Wherein RV is the retention volume in milliliters and peak width is in milliliters, peak maximum is the maximum position of the peak, tenth height is 1 / 10 the height of the peak maximum, and wherein post-peak refers to the tail of the peak whose retention volume is later than the peak maximum, and wherein front-peak refers to the front of the peak whose retention volume is earlier than the peak maximum. The plate count of the chromatography system should be greater than 20,000 and the symmetry should be between 0.98 and 1.22.

[0080] The samples were prepared semi-automatically using the PolymerChar "Instrument Control" software, with a target sample weight of 2 mg / mL and solvent (containing 200 ppm BHT) added to a septum-capped vial previously sparged with nitrogen via a PolymerChar high-temperature autosampler. The samples were dissolved at 160 degrees Celsius for 2 hours with "low speed" shaking.

[0081] Based on the GPC results using the internal IR5 detector (measurement channel) of the PolymerChar GPC-IR spectrometer according to Equations 6-8, the TM Calculations of Mn(conv), Mw(conv), and Mz(conv) were performed using the IR software, the baseline-subtracted IR chromatogram at each equally spaced data collection point (i), and the polyethylene equivalent molecular weight obtained from the narrow standard calibration curve at point (i) according to Equation 1.

[0082]

[0083]

[0084]

[0085] In the low molecular weight region of a GPC elution curve, when there is a significant peak known to be caused by the presence of antioxidants or other additives, the presence of such a peak will lead to an underestimation of the number average molecular weight (Mn) of the polymer sample, thereby giving an overestimation of the sample polydispersity, defined as Mw / Mn, where Mw is the weight average molecular weight. Therefore, by excluding this additional peak, the true polymer sample molecular weight distribution can be calculated from the GPC elution curve. This process is commonly described as peak skimming in data processing programs in liquid chromatography analysis. In this method, this additional peak is skimmed from the GPC elution curve before performing the sample molecular weight calculation from the GPC elution curve. The plate count of the chromatography system should be greater than 24,000, and the degree of symmetry should be between 0.98 and 1.22.

[0086] To monitor the deviation over time, a flow rate marker (decane) was introduced into each sample via a micropump controlled by the PolymerChar GPC-IR system. This flow rate marker (FM) was used to linearly correct the pump flow rate for each sample (Flow Rate (Nominal)) by comparing the RV of the corresponding decane peak in the sample (RV (FM Sample)) with the RV of the decane peak in the narrow standard calibration (RV (FM Calibrated)). It was then assumed that any change in the decane marker peak time was related to a linear change in flow rate (Flow Rate (Effective)) throughout the run. To facilitate the highest accuracy in measuring the RV of the flow marker peak, a least squares fitting procedure was used to fit the peak of the flow marker concentration chromatogram to a quadratic equation. The first derivative of the quadratic equation was then used to solve for the true peak position. After calibrating the system based on the flow marker peak, the effective flow rate (relative to the narrow standard calibration) was calculated as Equation 9. TM The software completes the processing of the flow marker peaks.An acceptable flow rate correction is such that the effective flow rate should be within + / - 1% of the nominal flow rate.

[0087] Flow rate (effective) = flow rate ((nominal)) × (RV (FM calibration) / RV (FM sample)) (Equation 9)

[0088] The systematic method for determining the multi-detector offset was performed in a manner consistent with that published by Balke, Mourey et al. (Mourey and Balke, Chromatography Polym., Chapter 12, (1992)) (Balke, Thitiratsakul, Lew, Cheung, Mourey, Chromatography Polym., Chapter 13, (1992)) using the PolymerChar GPCOne TMThe software optimizes triple detector logarithmic (MW and IV) results from broad homopolymer polyethylene standards (Mw / Mn>3) with narrow standards column calibration results from a narrow standards calibration curve.

[0089] Absolute molecular weight data were obtained using PolymerChar GPCOne TM The software was developed in a manner consistent with that published by Zimm (Zimm, BH, Journal of Physical Chemistry, 16, 1099 (1948)) and Kratochvil (Kratochvil, P., Classical Light Scattering from Polymer Solutions, Elsevier, Oxford, NY (1987)). The total injected concentration used to determine the molecular weight was obtained from the mass detector area and the mass detector constant, which was derived from a suitable linear polyethylene homopolymer or one of the polyethylene standards of known weight average molecular weight. The calculated molecular weight (using GPCOne TM ) are obtained using the light scattering constants from one or more polyethylene standards mentioned below and a refractive index concentration coefficient dn / dc of 0.104. In general, the mass detector response (IR5) and the light scattering constant (using GPCOne TM Determination) should be made from linear standards with a molecular weight exceeding approximately 50,000 g / mol.

[0090] CDF calculation method

[0091] IR5 measurement detector ("CDF IR ”) and low-angle laser light scattering detectors (“CDF LS The calculation of the cumulative detector score (CDF) of ”) is done by the following steps.

[0092] 1) Linear Flow calibrates the chromatogram based on the relative retention volume ratios between the air peak of the sample and the air peak of a consistent narrow standard cocktail.

[0093] 2) Correct the light scattering detector offset relative to the refractometer as described in the Gel Permeation Chromatography (GPC) section.

[0094] 3) Calculate the molecular weight at each retention volume (RV) data slice based on the polystyrene calibration curve as described in the gel permeation chromatography (GPC) section modified by a polystyrene to polyethylene conversion factor of approximately (0.3950-0.44).

[0095] 4) Baselines were subtracted from the light scattering and refractometer chromatograms, and integration windows were set using standard GPC practice to ensure that all low molecular weight retention volume ranges observed in the refractometer chromatogram were integrated in the light scattering chromatogram (thus setting the highest RV limit in each chromatogram to the same index). Any material corresponding to less than 150 g / mol in either chromatogram was not included in the integration.

[0096] 5) Calculate the IR5 measurement sensor cumulative detector fraction (CDF) based on its baseline-subtracted peak height (H) from high molecular weight to low molecular weight (low to high retention volume) at each data slice (j) according to Equations 10A and 10B (CDF IR ) and the cumulative detector fraction (CDF) of the low-angle laser light scattering (LALLS) chromatogram LS ).

[0097]

[0098]

[0099] gpcBR branching index by triple detector GPC (3D-GPC)

[0100] The gpcBR branching index is determined by first calibrating the light scattering, viscosity, and concentration detectors as described above. The baseline is then subtracted from the light scattering, viscometer, and concentration chromatograms. The integration windows are then set to ensure integration of all low molecular weight retention volume ranges in the light scattering and viscometer chromatograms, which indicate the presence of detectable polymer from the infrared (IR5) chromatogram. Linear polyethylene standards are then used to establish polyethylene and polystyrene Mark-Houwink constants. After obtaining the constants, these two values ​​are used to construct two linear reference conventional calibration values ​​for polyethylene molecular weight and polyethylene intrinsic viscosity as a function of elution volume, as shown in equations (11) and (12):

[0101]

[0102] [η] PE =K PS MW PS α+1 / MW PE (Equation 12).

[0103] The gpcBR branching index is a robust method for characterizing long chain branching, as described in Yau, Wallace W., "Examples of Using 3D-GPC—TREF for Polyolefin Characterization," Macromol. Symp., 2007, 257, 29-45. This index avoids the "slice-by-slice" 3D-GPC calculations and branching frequency calculations traditionally used to determine g' values, in favor of the entire polymer detector area. From the 3D-GPC data, the peak area method can be used to obtain the absolute weight average molecular weight (Mw(abs)) of the sample bulk using a light scattering (LS) detector. This method avoids the "slice-by-slice" ratio of the light scattering detector signal to the concentration detector signal required in traditional g' determinations.

[0104] In the case of 3D-GPC, the sample intrinsic viscosity can also be obtained independently using equation (13). This area calculation provides higher accuracy because, as the overall sample area, it is less sensitive to changes caused by detector noise and 3D-GPC settings for baseline and integration limits. More importantly, the peak area calculation is not affected by detector volume offset. Similarly, the sample intrinsic viscosity (IV) is obtained with high accuracy by the area method shown in equation (13):

[0105]

[0106] where η spi represents the specific viscosity obtained from the viscometer detector.

[0107] To determine the gpcBR branching index, the light scattering elution area of ​​the sample polymer is used to determine the molecular weight of the sample. The viscosity detector elution area of ​​the sample polymer is used to determine the intrinsic viscosity (IV or [η]) of the sample.

[0108] Initially, the molecular weight and intrinsic viscosity of a linear polyethylene standard sample such as SRM1475a or equivalent are determined using conventional calibration values ​​("cc") for both molecular weight and intrinsic viscosity as a function of elution volume according to equations (14) and (15):

[0109]

[0110] Equation (15) is used to determine the gpcBR branching index:

[0111]

[0112] where [η] is the measured intrinsic viscosity, [η] ccis the intrinsic viscosity from conventional calibration, Mw is the measured weight average molecular weight, and Mw ,cc is the conventionally calibrated weight average molecular weight. The weight average molecular weight determined by light scattering (LS) is often referred to as the "absolute weight average molecular weight" or "Mw, Abs." The Mw, cc according to equation (7) using a conventional GPC molecular weight calibration curve ("conventional calibration") is often referred to as the "polymer chain backbone molecular weight," "conventional weight average molecular weight," and "Mw(conv)."

[0113] All statistical values ​​with a "cc" subscript were determined using their respective elution volumes, corresponding conventional calibrations, and concentrations (Ci) as described previously. Non-subscripted values ​​are based on measurements of mass detector, LALLS, and viscometer areas. Iteratively adjusted K PE The values ​​of are calculated until the gpcBR measured for the linear reference sample is zero. For example, the final values ​​of α and Log K determined for gpcBR in this particular case were 0.725 and -3.391 for polyethylene and 0.722 and -3.993 for polystyrene, respectively. Once the K and α values ​​have been determined using the procedure discussed previously, the procedure is repeated using the branched sample. The branched sample is analyzed using the final Mark-Houwink constant obtained from the linear reference as the best "cc" calibration value. For linear polymers, the gpcBR calculated by equation (15) will be close to zero because the values ​​measured by LS and viscometry will be close to the conventional calibration standard. For branched polymers, the gpcBR will be above zero, especially for high levels of long chain branching because the measured polymer molecular weight will be higher than the calculated Mw,cc, and the calculated IVcc will be higher than the measured polymer IV. In effect, the gpcBR value represents the fractional IV change due to the molecular size shrinkage effect as a result of polymer branching. A gpcBR value of 0.5 or 2.0 implies a molecular size contraction effect of 50% and 200%, respectively, on the IV relative to an equivalent linear polymer molecule. For these specific examples, the advantage of using gpcBR over traditional "g' index" and branching frequency calculations is due to its higher precision. All parameters used in the gpcBR index determination are obtained with good precision and are not adversely affected by low 3D-GPC detector response at high molecular weights from the concentration detector. Errors in detector volume alignment also do not affect the accuracy of the gpcBR index determination.

[0114] curvature

[0115] The amount of curvature was measured via optical microscopy. The amount of curvature was calculated based on the inverse of the radius of the helix formed by the fiber. This is equal to the radius of the circle formed by the projection of the helix formed by the fiber on a surface perpendicular to it. The average of at least 5 measurements was reported. The measurements were expressed in 1 / mm (mm).-1 ) is reported by the unit.

[0116] Center of mass offset

[0117] The fibers were subjected to a 30-minute vapor dyeing zone to obtain electron beam stability. The dye solution was an aqueous solution of 2% by weight ruthenium (III) chloride hydrate and 6% by weight sodium hypochlorite. The fibers were exposed to the vapor in a 75 ml screw-top jar at ambient temperature. A Bruker Nova scanning electron microscope (SEM) was operated at an accelerating voltage of 5 kV, a spot size of 4.5, a working distance between 5 mm and 8 mm, an objective lens aperture of 40 microns, and a scan rate of 45 microseconds. Images were collected from secondary electron emission by an Everhardt-Thornly detector. Image Metrology SPIP 6.7.8 image analysis software was used for quantitative measurements. The diameter of the fiber cross section was measured using a single plug cord, and this measurement was divided into two halves to mark the midpoint as the fiber center of mass (C f The core area of ​​the bicomponent fiber is divided by two cords at 90° to visually create four quadrants of equal area, and the intersection of the two cords defines the centroid of the core area (C r2 ). Measure the fiber centroid (C f ) and the center of mass of the core region (C r2 ) and then divided by the radius of the fiber to calculate the fiber center of mass offset (P r2 / r).

[0118] Example

[0119] The development resin ("Resin 1") was prepared according to the following method and table.

[0120] All raw materials (monomers and comonomers) and process solvents (narrow boiling range high purity isoparaffin solvents, commercially available under the trade name Isopar E from ExxonMobil) were purified with molecular sieves before introduction into the reaction environment. Hydrogen was supplied under pressure as a high purity grade without further purification. The reactor monomer feed stream was pressurized to a pressure above the reaction pressure via a mechanical compressor. The solvent and comonomer feeds were pressurized to a pressure above the reaction pressure via a pump. Individual catalyst components were manually diluted in batches with purified solvents and pressurized to a pressure above the reaction pressure. All reaction feed streams were measured with mass flow meters and independently controlled using a computer-automated valve control system.

[0121] A single reactor system is used. The reactor is a continuous solution polymerization reactor consisting of a liquid-filled non-adiabatic isothermal circulating loop reactor that simulates a continuous stirred tank reactor (CSTR) with heat removal. All fresh solvent, monomer, comonomer, hydrogen, and catalyst component feeds can be controlled independently. The temperature of the total fresh feed stream (solvent, monomer, comonomer, and hydrogen) entering each reactor is controlled by passing the feed stream through a heat exchanger, typically between 15°C and 50°C, to maintain a single solution phase. The total fresh feed to the polymerization reactor is injected into the reactor at two locations, with the reactor volume between each injection location being approximately equal. The fresh feed is controlled by receiving half of the total fresh feed mass flow rate with each injector. The catalyst components are injected into the polymerization reactor through an injection nozzle to introduce these components into the center of the reactor flow. The main catalyst component feed is computer-controlled to maintain the reactor monomer conversion at a specified value. The co-catalyst component is fed based on a calculated specified molar ratio to the main catalyst component. Immediately following each reactor feed injection location, the feed stream is mixed with the circulating polymerization reactor contents using a static mixing element. The contents of each reactor are continuously circulated through a heat exchanger which removes most of the heat of reaction and where the temperature on the coolant side maintains an isothermal reaction environment at the specified temperature. Circulation around each reactor loop is provided by a pump.

[0122] The reactor effluent enters a zone where it is deactivated by adding and reacting with a suitable reagent (water). At this same reactor outlet location, other additives are added for polymer stabilization.

[0123] After catalyst deactivation and additive addition, the reactor effluent enters a devolatilization system where polymer is removed from the non-polymer stream. The separated polymer melt is pelletized and collected. The non-polymer stream passes through various devices that separate the majority of the ethylene removed from the system. Most of the solvent and unreacted comonomer are recycled back to the reactor after passing through a purification system. Small amounts of solvent and comonomer are purged from the process.

[0124] Figure 2 The reactor stream feed data flows are depicted diagrammatically in , which correspond to the values ​​in Table 2 for producing Resin 1. The data are presented so that the complexity of the solvent recycle system can be considered, and the reaction system can be more simply treated as a once-through flow diagram.

[0125] Table 1 - Catalyst Information

[0126]

[0127] Table 2-Production conditions

[0128]

[0129] Table 3 contains the melt index and density data for Resin 1.

[0130] Table 3 – Properties of Resin 1

[0131] sample <![CDATA[Melt index I2 (g / 10 min) at 190 °C]]> <![CDATA[Density (g / cm 3 )]]> Resin 1 19 0.9500

[0132] The following materials were used in the examples.

[0133] Polymer 1 (Poly.1) is 80% by weight of ASPUN TM 6835A and 20 wt% DOW TM 722 low density polyethylene resin polymer blend. ASPUN TM 6835A is a kind of stainless steel with a density of 0.9500g / cm 3 and an ethylene / α-olefin interpolymer and a linear low density polyethylene fiber resin having a melt index (I2) of 17 and is commercially available from The Dow Chemical Company, Midland, Michigan. TM 722 low density polyethylene resin is a kind of low density polyethylene resin with a density of 0.918g / cm 3 and a low density polyethylene having a melt index (I2) of 8 and is commercially available from The Dow Chemical Company, Midland, Michigan.

[0134] Polymer 2 (Poly.2) is 20 wt% DOW TM A polymer blend of 722 low density polyethylene resin and 80 wt% of Resin 1.

[0135] Polymer 3 (Poly.3) is 100% by weight of ASPUN TM 6835A.

[0136] Polymer 4 (Poly. 4) is 100% by weight of Resin 1.

[0137] Polymer 5 is 80 wt% of Resin 1 and 20 wt% of DOW TM DMDA-8007NT 7 High density polyethylene resin polymer blend. DOW TM The density of DMDA-8007NT 7 high-density polyethylene resin is 0.965g / cm 3 and has a melt index (I2) of 8.3 and is commercially available from The Dow Chemical Company, Midland, Michigan.

[0138] Polymers 1 through 5 are the materials used to form the first region of the bicomponent fiber, as discussed further below.

[0139] Polymer 6 is commercially available from Eastman Chemical Company, Kingsport, TN. TM Polyester F61HC. Polymer 6 was used to form the second region of the bicomponent fiber, as discussed below.

[0140] The CDFs of polymers 1 to 5 with molecular weights greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC) are reported in Table 4. LS and a CDF having a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC) IR .

[0141] Table 4 - First Region - CDF Data

[0142] <![CDATA[CDF LS ]]> <![CDATA[CDF IR ]]> Polymer 1 0.3268 0.0356 Polymer 2 0.3015 0.0280 Polymer 3 0.1006 0.0086 Polymer 4 0.0105 0.0005 Polymer 5 0.0698 0.0057

[0143] Conventional GPC measurements of the first region polymers, Mn, Mw, Mz, and Mw / Mn, are reported in Table 5.

[0144] Table 5 - First Region - Conventional GPC Data

[0145] Mn(GPC) Mw(GPC) Mz(GPC) Mw(GPC) / Mn(GPC) Polymer 1 16,067 78,893 431,870 4.91 Polymer 2 21,556 72,606 383,147 3.37 Polymer 3 16,632 55,186 160,743 3.32 Polymer 4 27,877 47,483 81,470 2.17 Polymer 5 21,301 54,088 133,291 2.54

[0146] The absolute GPC measurements Mn(Abs) and Mw(Abs) and Mw(Abs) / Mw(GPC) values ​​for Polymers 1 to 5 are reported in Table 6. In addition, the gpcBR branching index measurements for Polymers 1 to 5 are reported in Table 6.

[0147] Table 6 - First Region - Absolute GPC and gpcBR Data

[0148] Mn(Abs) Mw(Abs) Mw(Abs) / Mw(GPC) gpcBR Polymer 1 14,508 146,623 1.86 1.1293 Polymer 2 20,037 132,607 1.83 1.09282 Polymer 3 15,719 61,531 1.11 0.1891 Polymer 4 19,975 47,563 1.00 0.079 Polymer 5 19,792 56,200 1.04 0.13847

[0149] Fiber formation

[0150] The fibers were spun on a Hills bicomponent continuous filament spinning line. Bicomponent fibers with an eccentric core-sheath configuration were produced. The fibers were spun on the Hills line according to the following conditions. The extruder profile was adjusted to achieve a melt temperature of 240°C. The throughput rate for each hole was 1.5 ghm (grams per minute per hour). A Hills bicomponent die was used and operated at a 40 / 60 core / sheath ratio (by weight) to form Examples 1 and 2 of the present invention, and Comparative Examples 3, 4, and 5, wherein the first region (sheath) was in one extruder and the second region (core) was in another extruder according to Table 7 below. The die consisted of 144 holes with a hole diameter of 0.6 mm and a length / diameter (L / D) ratio of 4 / 1. The quench air temperature and flow rate were set to 21°C-24°C and 420 cfm (cubic feet per minute), respectively. After the quench zone, tensile tension was applied to the 144 filaments by pneumatically entraining the filaments with an air stream in a slot unit. The air stream velocity was controlled by the slot aspirator pressure.

[0151] Table 7 - Fiber Examples

[0152]

[0153] The CDF values ​​of the molecular weight greater than or equal to 1,000,000 g / mol obtained using gel permeation chromatography (GPC) for Examples 1 and 2 of the present invention and Comparative Examples 1, 2, and 3 are reported in Table 8. LS and a CDF having a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC) IR .

[0154] Table 8 – Fiber Data

[0155] <![CDATA[CDF LS ]]> <![CDATA[CDF IR ]]> Embodiment 1 of the present invention 0.2838 0.0294 Embodiment 2 of the present invention 0.2723 0.0246 Comparative Example 1 0.1444 0.0092 Comparative Example 2 0.0000 0.0004 Comparative Example 3 0.0825 0.0053

[0156] Table 9 shows the curvature data related to the examples. LS and CDF IR And contains higher Mw(Abs), Mw(Abs) / Mw(GPC), gpcBR, CDF LS and CDF IR The first region polymers of Inventive Example 1 and Inventive Example 2 have significantly higher curvatures than that of the comparative example.

[0157] Table 9 – Curvature data

[0158]

Claims

1. A bicomponent fiber, comprising: fiber centroid; a first region having a first centroid and a second region having a second centroid; The first region comprises from 50 wt% to 90 wt% of an ethylene / α-olefin interpolymer, based on the total weight of the first region, and from 10 wt% to 40 wt% of a low density polyethylene, based on the total weight of the first region; The first region has a light scatter cumulative detector fraction (CDF) greater than 0.1200 LS ), where the light scatter cumulative detector fraction (CDF LS ) is calculated by measuring the area fraction of the low-angle laser light scattering (LALLS) detector chromatogram of molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC); the infrared cumulative detector fraction (CDF) greater than 0.0100 IR ), where the infrared cumulative detector fraction (CDF IR ) is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram having a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC); and a ratio M expressed as a weight average molecular weight to a number average molecular weight greater than 3.

35. w(GPC) / M n(GPC) Molecular weight distribution; the second region comprises polyester; and wherein at least one of the first centroid and the second centroid is different from the fiber centroid, wherein the first region and the second region are arranged in a side-by-side or split pie configuration, or in an eccentric core-sheath configuration, wherein when the first region and the second region are arranged in an eccentric core-sheath configuration, the first region is the sheath of the bicomponent fiber and the second region is the core of the bicomponent fiber, and the sheath region surrounds the core region; wherein the curvature of the bicomponent fiber is at least 1.10 mm -1 .

2. The bicomponent fiber of claim 1, wherein the ethylene / α-olefin interpolymer has a density of 0.910 g / cm 3 to 0.964g / cm 3 The melt index (I2) measured according to ASTM D1238, 190° C., 2.16 kg is in the range of 10 g / 10 min to 60 g / 10 min.

3. The bicomponent fiber of claim 1, wherein the first region comprises 10 to 30 weight percent of the low density polyethylene, based on the total weight of the first region.

4. The bicomponent fiber of claim 2, wherein the first region comprises 10 to 30 weight percent of the low density polyethylene, based on the total weight of the first region.

5. The bicomponent fiber of any one of claims 1 to 4, wherein the weight ratio of the first region to the second region is 90:10 to 10:

90.

6. A nonwoven comprising the bicomponent fiber according to any one of claims 1 to 5.

7. A bicomponent fiber, comprising: fiber centroid; a first region having a first centroid and a second region having a second centroid; The first region comprises from 50 wt% to 90 wt% of an ethylene / α-olefin interpolymer, based on the total weight of the first region, and from 10 wt% to 40 wt% of a low density polyethylene, based on the total weight of the first region; said second region comprising polyester; wherein at least one of the first centroid and the second centroid is different from the fiber centroid, wherein the first region and the second region are arranged in a side-by-side or split pie configuration, or in an eccentric core-sheath configuration, wherein when the first region and the second region are arranged in an eccentric core-sheath configuration, the first region is the sheath of the bicomponent fiber and the second region is the core of the bicomponent fiber, and the sheath region surrounds the core region; and wherein the fiber has a light scattering cumulative detector fraction (CDF) greater than 0.1600 LS ), where the light scatter cumulative detector fraction (CDF LS ) is calculated by measuring the area fraction of the low-angle laser light scattering (LALLS) detector chromatogram of molecular weight greater than or equal to 1,000,000 g / mol using gel permeation chromatography (GPC); the infrared cumulative detector fraction (CDF) greater than 0.0125 IR ), where the infrared cumulative detector fraction (CDF IR ) is calculated by measuring the area fraction of the IR5 measurement channel (IR) detector chromatogram having a molecular weight greater than or equal to 350,000 g / mol using gel permeation chromatography (GPC).

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