CN115516142A

CN115516142A - Bicomponent fibers comprising ethylene/alpha-olefin interpolymers

Info

Publication number: CN115516142A
Application number: CN202180033440.5A
Authority: CN
Inventors: 林倚剑; 张兰鹤; R·维沃斯; F·阿特亚加拉里奥斯
Original assignee: Dow Global Technologies LLC
Current assignee: Dow Global Technologies LLC
Priority date: 2020-05-08
Filing date: 2021-05-06
Publication date: 2022-12-23
Also published as: EP4146850A1; KR20230009910A; US20230257919A1; WO2021226300A1; JP2023524203A; AR122466A1; BR112022022450A2

Abstract

Bicomponent fibers are provided. The bicomponent fiber comprises a first region and a second region. The first region comprises a first ethylene/a-olefin interpolymer, and the second region comprises a second ethylene/a-olefin interpolymer. The first ethylene/a-olefin interpolymer has a maximum peak melting temperature (Tm) less than 130 ℃ and at least 3.5 ℃ greater than the maximum peak melting temperature of the second ethylene/a-olefin interpolymer. The bicomponent fibers can be used to form nonwovens with improved tensile strength, elongation at break, and/or abrasion resistance in various respects.

Description

Bicomponent fibers comprising ethylene/alpha-olefin interpolymers

Technical Field

Embodiments of the present disclosure generally relate to bicomponent fibers comprising ethylene/a-olefin interpolymers, and nonwovens comprising fibers.

Background

Bicomponent fibers are fibers comprised of two distinct regions and corresponding polymer compositions extruded from the same spinneret, wherein the same filament or fiber contains both compositions. As the fiber exits the spinneret, the fiber consists of unmixed components that melt at the interface. The two polymer compositions may differ in their chemical and/or physical properties. Bicomponent fibers can be formed by spinning techniques known in the art and can be used to form nonwovens. The nonwoven formed from bicomponent fibers may have similar or different properties than the nonwoven formed from monocomponent fibers. However, there are problems in developing high spinnability, fine denier bicomponent fibers and nonwovens made from such bicomponent fibers that are recyclable and have an excellent combination of softness, tensile strength, abrasion resistance and/or elongation at break.

Disclosure of Invention

Embodiments of the present disclosure provide bicomponent fibers that are strong and highly spinnable in all respects, as represented by high filament speed and low denier. Bicomponent fibers may be used to form nonwovens that are compatible with polyethylene recovery streams and may have a combination of enhanced tensile strength, abrasion resistance, and/or elongation at break. The bicomponent fiber includes a first region comprising a first ethylene/a-olefin interpolymer and a second region comprising a second ethylene/a-olefin interpolymer.

Disclosed herein is a bicomponent fiber. The bicomponent fiber comprises a first region and a second region; the first region comprises a first ethylene/a-olefin interpolymer having a maximum peak melting temperature (Tm) of less than 130 ℃; the second region comprises a second ethylene/a-olefin interpolymer having a density less than the density of the first ethylene/a-olefin interpolymer composition; wherein the highest peak melting temperature (Tm) of the first ethylene/a-olefin interpolymer is at least 3.5 ℃ greater than the highest peak melting temperature (Tm) of the second ethylene/a-olefin interpolymer; wherein the first region and the second region are arranged in a core-sheath configuration.

Also disclosed herein is a nonwoven. The nonwoven is formed from bicomponent fibers as disclosed herein. In embodiments, the nonwoven has one or more of the following properties: a fiber denier equal to or less than 1.5g/9000 m; a tensile strength under 20 grams per square meter (gsm) of the nonwoven in the machine direction of greater than 11.0 newtons per inch; an elongation to break in the machine direction of greater than 100% at 20gsm of the nonwoven; and less than 0.18mg/cm in the machine direction under 20gsm of the nonwoven ² The wear resistance of (2). In embodiments, a nonwoven formed from the bicomponent fibers disclosed herein is on an elution profile achieved via an Improved Comonomer Composition Distribution (ICCD) procedure at 40.0 ℃ to 68.0 ℃ (WT _40℃-68℃ ) Comprises at least 12 weight percent (wt%) of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer combined at a temperature range of from 40.0 ℃ to 68.0 ℃, wherein the weight percent at the temperature range of from 40.0 ℃ to 68.0 ℃ on the elution curve achieved via ICCD can be measured according to the test method described below.

Additional features and advantages of the embodiments will be set forth in the detailed description which 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 detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing and the following description 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 in and constitute a part of this specification.

Drawings

FIG. 1 is a schematic diagram of a single reactor data flow diagram.

FIG. 2 is a schematic diagram of a dual reactor dataflow graph.

FIG. 3 is an ICCD elution profile for inventive nonwoven example 2 showing temperature ranges from 40.0 ℃ to 68.0 ℃ (WT) with respect to temperature _40℃-68℃ ) W in the temperature range of _T (T)。

Detailed Description

Aspects of the disclosed bicomponent fibers are described in more detail below. Bicomponent fibers can be used to form nonwovens, and such nonwovens can have a wide variety of applications including, for example, wipes, masks, tissues, bandages, medical gowns, baby diapers, adult incontinence, and other medical and hygiene products. It should be noted, however, that this is merely an illustrative implementation of the embodiments disclosed herein. These embodiments are applicable to other technologies that are susceptible to similar problems as discussed above.

As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" and derivatives thereof, are not intended to exclude the presence of any additional component, step or procedure, whether or not such component, step or procedure is specifically disclosed. For the avoidance of any doubt, unless stated to the contrary, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise. In contrast, the term "consisting essentially of …" excludes any other components, steps or procedures from any subsequently enumerated range, except for those components, steps or procedures not essential to operability. The term "consisting of …" excludes any component, step, or procedure not specifically recited or listed.

As used herein, the term "interpolymer" refers to a polymer 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.

As used herein, the term "polymer" means a polymeric compound prepared by polymerizing monomers, whether of the same type or of different types. The term polymer thus encompasses the term homopolymer (used to refer to polymers prepared from only one type of monomer, it being understood that trace impurities may be incorporated into the polymer structure) and the term interpolymer as defined below. The polymer may be a single polymer or a blend of polymers.

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 which are inserted randomly, rather than in an identifiable manner as in a knitted fabric.

As used herein, the term "spunbond" refers to the manufacture of a nonwoven fabric comprising the steps of: (a) Extruding molten thermoplastic strands from a plurality of fine capillaries, known as spinnerets; (b) Quenching the strands with a stream of generally cooled air to accelerate solidification of the molten strands; (c) Attenuating the strand by advancing the strand through a quench zone having a tensile tension that can be applied by pneumatically entraining the strand in an air stream or by wrapping the strand around a mechanical draw roll of the type commonly used in the textile fiber industry; (d) Collecting the stretched strands as a mesh on a foraminous surface (e.g., a moving screen or porous belt); and (e) bonding the web of loose strands into a nonwoven fabric. Bonding may be accomplished by a variety of means including, but not limited to, a thermal calendaring process, an adhesive bonding process, a hot air bonding process, a needle punching process, a hydroentangling process, and combinations thereof.

As used herein, the term "meltblown" refers to a nonwoven fabric made via a process that generally includes the steps of: (a) extruding molten thermoplastic strands from a spinneret; (b) Simultaneously quenching and attenuating the polymer stream using a high velocity heated air stream directly below the spinneret; (c) The stretched strands are collected as a web on a collection surface. Meltblown webs can be bonded by a variety of means including, but not limited to, autogenous bonding (i.e., self bonding without further treatment), hot calendaring processes, adhesive bonding processes, hot air bonding processes, needle punching processes, hydroentangling processes, and combinations thereof.

The bicomponent fibers may comprise a combination of two or more suitable embodiments as disclosed herein.

The nonwoven formed from bicomponent fibers may comprise a combination of two or more suitable embodiments as disclosed herein.

Fiber

Bicomponent fibers according to embodiments of the present disclosure can be formed into fibers via different techniques (e.g., via melt spinning). In melt spinning, the first and second zones can be melted, coextruded, and forced through a metal plate, a fine orifice in a spinneret, into air or other gas, where the coextruded zones are cooled and solidified to form a bicomponent fiber. The solidified filaments may be withdrawn via air jets, rotating rolls, or godets and may be laid down as a web on a conveyor belt to form a nonwoven. Bicomponent fibers according to embodiments of the present disclosure contain two regions (i.e., a first region and a second region). The region may be configured in a core-sheath configuration (i.e., the concentric core-sheath or islands-in-the-sea configuration referred to herein). For example, in embodiments, the first region and the second region are arranged in a concentric core-sheath configuration, wherein the first region is the core region and the second region is the sheath region, and the sheath region surrounds the core region. In other embodiments, the first region and the second region are arranged in a core-sheath, islands-in-the-sea configuration, wherein the first region is a plurality of core regions (also referred to as islands) and the second region is a sheath region (also referred to as sea), and the sheath region or sea surrounds the plurality of core regions or islands.

In embodiments, 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 10 to 90. All individual values and subranges of the ratio of 90. For example, in embodiments, the weight ratio of the first region to the second region may be from 80 to 20, from 30 to 30.

In embodiments, the bicomponent fibers have a denier of less than 50g/9000m. All individual values and subranges from less than 50g/9000m are disclosed and included herein. For example, the denier of the bicomponent fiber may be less than 40g/9000m, less than 30g/9000m, less than 20g/9000m, less than 10g/9000m, less than 5g/9000m, less than 3g/9000m, less than 2g/9000m, less than 1.5g/9000m, or less than 1.2g/9000m, or the denier thereof may be in the following range: 0.1g/9000m to 50g/9000m, 0.1g/9000m to 40g/9000m, 0.1g/9000m to 30g/9000m, 0.1g/9000m to 20g/9000m, 0.1g/9000m to 10g/9000m, 0.1g/9000m to 5g/9000m, 0.1g/9000m to 2.0g/9000m, 0.1g/9000m to 1.5g/9000m, 0.1g/9000m to 1.2g/9000m, 1g/9000m to 50g/9000m, 1g/9000m to 40g/9000m, 1g/9000m to 30g/9000m, 1g/9000m to 20g/9000m, 1g/9000m to 10g/9000m, 9000m to 1g/9000m, or 1g/9000m to 20g/9000m, wherein denier may be measured according to the test method described below.

First region

The first region of the bicomponent fiber comprises a first ethylene/a-olefin interpolymer.

In embodiments, the first region of the bicomponent fiber comprises the first ethylene/a-olefin interpolymer in an amount of at least 50 weight percent (wt%), based on the total weight of the first region. All individual values and subranges from at least 50 weight percent are disclosed and included herein. For example, in embodiments, the first region may comprise the first ethylene/a-olefin interpolymer in an amount of at least 50 weight percent, at least 60 weight percent, at least 75 weight percent, at least 85 weight percent, at least 90 weight percent, at least 95 weight percent, or at least 99 weight percent, based on the total weight of the first region. In other embodiments, the first region may comprise the first ethylene/a-olefin interpolymer in an amount from 50 to 100, 60 to 100, 75 to 100, 85 to 100, 90 to 100, 95 to 100, 99 to 100, 50 to 95, 60 to 95, 75 to 95, 85 to 95, or 90 to 95 weight percent, based on the total weight of the first region.

The term "ethylene/a-olefin interpolymer" refers to a polymer comprising ethylene and an a-olefin having 3 or more carbon atoms. In embodiments, the first ethylene/a-olefin interpolymer comprises greater than 55% by weight of units derived from ethylene and less than 45% by weight of units derived from one or more a-olefin comonomers (based on the total amount of polymerizable monomers). All individual values and subranges from greater than 55 weight percent of units derived from ethylene and less than 45 weight percent of units derived from one or more alpha-olefin comonomers are included herein and disclosed herein. For example, in embodiments, the first ethylene/a-olefin interpolymer may comprise (a) greater than 55%, greater than 70%, greater than 85%, greater than 90%, greater than 92%, greater than 95%, greater than 97%, greater than 98%, greater than 99%, greater than 99.5%, or 55% to 99.5%, 55% to 95%, 55% to 90%, 55% to 99.5%, 55% to 99%, 55% to 97%, 55% to 94%, 75% to 90%, 90% to 99.9%, 90% to 99.5%, 90% to 97%, or 90% to 95% by weight of units derived from ethylene; and (b) less than 45%, less than 30%, 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% or 0.1% to 45%, 0.1% to 25%, 0.1% to 10%, 0.1% to 5%, 0.5% to 20%, 0.5% to 10%, 0.5% to 5%, 1% to 20%, 1% to 10%, 1% to 5%, 5% to 20%, or 5% to 10% by weight of units derived from one or more alpha-olefin comonomers. Comonomer content can be measured using any suitable technique, such as techniques based on nuclear magnetic resonance ("NMR") spectroscopy, and for example, by techniques such as those described in U.S. Pat. No. 7,498,282 ¹³ C NMR analysis, which is incorporated herein by reference.

Suitable alpha-olefin comonomers typically have no more than 20 carbon atoms. The one or more alpha-olefins of the first ethylene/alpha-olefin interpolymer may be selected from the group consisting of: C3-C20 acetylenically unsaturated monomers and C4-C18 diolefins. For example, the alpha-olefin comonomer can have 3 to 10 carbon atoms or 3 to 8 carbon atoms. Exemplary alpha-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. The one or more alpha-olefin comonomers of the first ethylene/alpha-olefin interpolymer may, for example, be selected from the group consisting of: propylene, 1-butene, 1-hexene and 1-octene; or in the alternative, selected from the group consisting of: 1-butene, 1-hexene and 1-octene; or in the alternative, selected from the group consisting of: 1-hexene and 1-octene. In one or more embodiments, the first ethylene/a-olefin interpolymer may comprise greater than 0% and less than 45% by weight of units derived from one or more of 1-octene, 1-hexene, or 1-butene comonomers.

In embodiments, the density of the first ethylene/α -olefin interpolymer is at 0.940g/cm ³ To 0.965g/cm ³ Within the range of (1). Disclosed herein and included at 0.940g/cm ³ To 0.965g/cm ³ All individual values and subranges of density within the range of (a). For example, the first ethylene/α -olefin interpolymer may have a density of 0.940g/cm ³ To 0.965g/cm ³ 、0.940g/cm ³ To 0.960g/cm ³ 、0.945g/cm ³ To 0.965g/cm ³ 、0.945g/cm ³ To 0.960g/cm ³ 、0.950g/cm ³ To 0.965g/cm ³ Or 0.950g/cm ³ To 0.960g/cm ³ Wherein the density can be measured according to ASTM D792.

In embodiments, the first ethylene/α -olefin interpolymer has a melt index (I2) measured according to ASTM D1238, 190 ℃,2.16kg in the range of from 10g/10min to 60g/10 min. All individual values and subranges from 10g/10min to 60g/10min are included herein and disclosed herein. For example, in some embodiments, the melt index (I2) of the first ethylene/a-olefin interpolymer can be in a range from 10g/10min to 60g/10min, 10g/10min to 50g/10min, 10g/10min to 40g/10min, 10g/10min to 30g/10min, 10g/10min to 20g/10min, 20g/10min to 60g/10min, 20g/10min to 50g/10min, 20g/10min to 40g/10min, 20g/10min to 30g/10min, 15g/10min to 60g/10min, 15g/10min to 50g/10min, 15g/10min to 40g/10min, 15g/10min to 30g/10min, or 15g/10min to 20g/10min, wherein the melt index (I2.16 kg) can be measured according to ASTM D1238, 190 ℃.

In embodiments, the molecular weight distribution of the first ethylene/a-olefin interpolymer is determined by conventional Gel Permeation Chromatography (GPC) and is expressed as a ratio of weight average molecular weight to number average molecular weight (M) from 1.5 to 5.0 _w(GPC) /M _n(GPC) ). Molecular weight distributions (M) from 1.5 to 5.0 are disclosed and included herein _w(GPC) /M _n(GPC) ) All individual values and subranges of (a). For example, the molecular weight distribution (M) of the first ethylene/α -olefin interpolymer _w(GPC) /M _n(GPC) ) Can be 1.5 to 5.0, 1.5 to 4.0, 1.5 to 3.0, 1.5 to 2.5, 2.0 to 5.0, 2.0 to 4.0, 2.0 to 3.0, or 2.0 to 2.5, wherein the molecular weight distribution (M) can be measured according to conventional GPC testing methods described below _w(GPC) /M _n(GPC) )。

In embodiments, the first region may comprise additional components, such as one or more other polymers and/or one or more additives. Other polymers may include another ethylene/α -olefin interpolymer, a post-consumer or post-industrial recycled polymer, 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 additional polymer may be up to 50 weight percent based on the total weight of the first region. For example, in embodiments, the first region may comprise up to 50 wt% of a propylene-based plastomer or propylene-based elastomer, such as VERSIFY available from The Dow Chemical Company ^TM Polymers and VISTA AXX available from ExxonMobil Chemical Co ^TM Polymers), low modulus and/or low molecular weight polypropylenes (such as L-MODU from white light (Idemitsu) ^TM Polymers), random copolymerized propylene or propylene-based olefin block copolymers (such as INTUNE) ^TM ). Potential additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers, pigments, primary antioxidants (primary antioxidants), secondary antioxidants (secondary antioxidants), processing aids, UV stabilizers, antiblocking agents, slip agents, tackifiers, flame retardants, biocides, deodorants, and the likeAgents, antifungal agents, and combinations thereof. The first region may comprise from about 0.01 or 0.1 or 1 to about 25 or about 20 or about 15 or about 10 or about 5 weight percent of the additive based on the total weight of the first region, combined weight.

In embodiments, the first ethylene/a-olefin interpolymer has a highest peak melting temperature (Tm) of less than 130 ℃ when measured according to the Differential Scanning Calorimetry (DSC) test method described below. All individual values and subranges from less than 130 ℃ are disclosed and incorporated herein. For example, in embodiments, the highest peak melting temperature (Tm) of the first ethylene/a-olefin interpolymer can be less than 130 ℃, less than 129.5 ℃, less than 129 ℃, or less than 128.5 ℃, or can be in the range of 120 ℃ to 130 ℃, 125 ℃ to 130 ℃, 127 ℃ to 130 ℃, 128 ℃ to 130 ℃, 125 ℃ to 129.5 ℃, 126 ℃ to 129 ℃, 126 ℃ to 128 ℃, 127 ℃ to 129 ℃, 127 ℃ to 128.5 ℃, or 127 ℃ to 128 ℃ when measured according to the DSC test method described below.

In embodiments, the maximum peak crystallization temperature (Tc) of the first ethylene/a-olefin interpolymer is in the range of from 108 ℃ to 118 ℃, wherein the maximum peak crystallization temperature (Tc) can be measured according to the DSC test method described below. All individual values and subranges from 108 ℃ to 118 ℃ are disclosed and included herein. For example, the highest peak crystallization temperature (Tc) of the first ethylene/a-olefin interpolymer may be in the range of 108 ℃ to 118 ℃, 110 ℃ to 118 ℃, 112 ℃ to 118 ℃, 108 ℃ to 116 ℃, 108 ℃ to 115 ℃, 110 ℃ to 116 ℃, 110 ℃ to 115 ℃, 112 ℃ to 116 ℃, or 113 ℃ to 115 ℃ when measured according to the DSC test method described below.

Second region

The second region of the bicomponent fiber comprises a second ethylene/a-olefin interpolymer.

In embodiments, the second region of the bicomponent fiber comprises the second ethylene/a-olefin interpolymer in an amount of at least 50 weight percent (wt%), based on the total weight of the second region. All individual values and subranges from at least 50 weight percent are disclosed and included herein. For example, in embodiments, the second region can comprise the second ethylene/a-olefin interpolymer in an amount of at least 50 weight percent, at least 60 weight percent, at least 75 weight percent, at least 85 weight percent, at least 90 weight percent, at least 95 weight percent, or at least 99 weight percent, based on the total weight of the second region. In other embodiments, the second region can comprise the second ethylene/a-olefin interpolymer in an amount from 50 to 100, 60 to 100, 75 to 100, 85 to 100, 90 to 100, 95 to 100, 99 to 100, 50 to 95, 60 to 95, 75 to 95, 85 to 95, or 90 to 95 weight percent, based on the total weight of the second region.

In embodiments, the second ethylene/a-olefin interpolymer comprises greater than 55 weight percent units derived from ethylene and less than 45 weight percent units derived from one or more a-olefin comonomers (based on the total amount of polymerizable monomers). All individual values and subranges from greater than 55 weight percent of units derived from ethylene and less than 45 weight percent of units derived from one or more alpha-olefin comonomers are included herein and disclosed herein. For example, the second ethylene/a-olefin interpolymer can comprise (a) greater than 55%, greater than 70%, greater than 85%, greater than 90%, greater than 92%, greater than 95%, greater than 97%, greater than 98%, greater than 99%, greater than 99.5%, or 55% to 99.5%, 55% to 95%, 55% to 90%, 55% to 99.5%, 55% to 99%, 55% to 97%, 55% to 94%, 75% to 90%, 90% to 99.9%, 90% to 99.5%, 90% to 97%, or 90% to 95% by weight of units derived from ethylene; and (b) less than 45%, less than 30%, 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% or 0.1% to 45%, 0.1% to 25%, 0.1% to 10%, 0.1% to 5%, 0.5% to 20%, 0.5% to 10%, 0.5% to 5%, 1% to 20%, 1% to 10%, 1% to 5%, 5% to 20%, or 5% to 10% by weight of units derived from one or more alpha-olefin comonomers. Comonomer content can be measured using any suitable technique, such as techniques based on nuclear magnetic resonance ("NMR") spectroscopy, and for example, by techniques such as those described in U.S. Pat. No. 7,498,282 ¹³ Measured by C NMR analysis, which is incorporated by referenceHerein incorporated.

Suitable alpha-olefin comonomers typically have no more than 20 carbon atoms. The one or more alpha-olefins of the second ethylene/alpha-olefin interpolymer may be selected from the group consisting of: C3-C20 acetylenically unsaturated monomers and C4-C18 diolefins. For example, the alpha-olefin comonomer can have 3 to 10 carbon atoms or 3 to 8 carbon atoms. Exemplary alpha-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. The one or more alpha-olefin comonomers of the second ethylene/alpha-olefin interpolymer may, for example, be selected from the group consisting of: propylene, 1-butene, 1-hexene and 1-octene; or in the alternative, selected from the group consisting of: 1-butene, 1-hexene and 1-octene; or in the alternative, selected from the group consisting of: 1-hexene and 1-octene. In one or more embodiments, the second ethylene/a-olefin interpolymer may comprise greater than 0% and less than 45% by weight of units derived from one or more of 1-octene, 1-hexene, or 1-butene comonomers.

In embodiments, the second ethylene/a-olefin interpolymer has a density less than the density of the first ethylene/a-olefin interpolymer. In embodiments, the density of the first ethylene/a-olefin interpolymer is at least 0.022g/cm greater than the density of the second ethylene/a-olefin interpolymer ³ . Included and disclosed herein is at least 0.022g/cm ³ All individual values and subranges of (a); for example, the first ethylene/α -olefin interpolymer can have a density at least 0.022g/cm greater than the density of the second ethylene/α -olefin interpolymer ³ 、0.025g/cm ³ 、0.027g/cm ³ 、0.029g/cm ³ 、0.031g/cm ³ 、0.033g/cm ³ 、0.035g/cm ³ 、0.037g/cm ³ 、0.039g/cm ³ Or 0.041g/cm ³ Wherein the density can be measured according to ASTM D792. In other embodiments, the difference in density of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer is at 0.023g/cm ³ To 0.085g/cm ³ 、0.023g/cm ³ To 0.050g/cm ³ 0.023g/cm3 to 0.040g/cm ³ 、0.029g/cm ³ To 0.085g/cm ³ 、0.029g/cm ³ To 0.050g/cm ³ 、0.031g/cm ³ To 0.085g/cm ³ 、0.031g/cm ³ To 0.050g/cm ³ 、0.031g/cm ³ To 0.040g/cm ³ 、0.039g/cm ³ To 0.050g/cm ³ Or 0.039g/cm ³ To 0.085g/cm ³ Wherein the density can be measured according to ASTM D792.

In embodiments, the density of the second ethylene/α -olefin interpolymer is at 0.880g/cm ³ To 0.940g/cm ³ Within the range of (1). Disclosed herein and included at 0.880g/cm ³ To 0.940g/cm ³ All individual values and subranges of density within the range of (a). For example, in some embodiments, the second ethylene/a-olefin interpolymer can have a density at 0.880cm ³ To 0.940g/cm ³ 、0.880g/cm ³ To 0.930g/cm ³ 、0.880g/cm ³ To 0.920g/cm ³ 、0.890g/cm ³ To 0.940g/cm ³ 、0.890g/cm ³ To 0.930g/cm ³ 、0.890g/cm ³ To 0.920g/cm ³ 、0.890g/cm ³ To 0.910g/cm ³ 、0.900g/cm ³ To 0.940g/cm ³ 、0.900g/cm ³ To 0.930g/cm ³ 、0.900g/cm ³ To 0.920g/cm ³ Or 0.900g/cm ³ To 0.910g/cm ³ Wherein the density can be measured according to ASTM D792.

In embodiments, the second ethylene/α -olefin interpolymer has a melt index (I2) measured according to ASTM D1238, 190 ℃,2.16kg in the range of from 10g/10min to 60g/10 min. All individual values and subranges from 10g/10min to 60g/10min are included herein and disclosed herein. For example, in some embodiments, the melt index (I2) of the second ethylene/a-olefin interpolymer can be in a range from 10g/10min to 60g/10min, 10g/10min to 50g/10min, 10g/10min to 40g/10min, 10g/10min to 30g/10min, 10g/10min to 20g/10min, 20g/10min to 60g/10min, 20g/10min to 50g/10min, 20g/10min to 40g/10min, 20g/10min to 30g/10min, 15g/10min to 60g/10min, 15g/10min to 50g/10min, 15g/10min to 40g/10min, 15g/10min to 30g/10min, or 15g/10min to 20g/10min, wherein the melt index (I2.16 kg) can be measured according to ASTM D1238, 190 ℃.

In embodiments, the second ethylene/a-olefin interpolymer has a molecular weight distribution, expressed as a ratio of weight average molecular weight to number average molecular weight (M) from 1.5 to 5.0 _w(GPC) /M _n(GPC) ). Molecular weight distributions (M) from 1.5 to 5.0 are disclosed and included herein _w(GPC) /M _n(GPC) ) All individual values and subranges of (a). For example, the molecular weight distribution (M) of the second ethylene/alpha-olefin interpolymer _w(GPC) /M _n(GPC) ) Can be 1.5 to 5.0, 1.5 to 4.0, 1.5 to 3.0, 1.5 to 2.5, 2.0 to 5.0, 2.0 to 4.0, 2.0 to 3.0, or 2.0 to 2.5, where the molecular weight distribution (M) can be measured according to the conventional Gel Permeation Chromatography (GPC) test method described below _w(GPC) /M _n(GPC) )。

In embodiments, the second region may comprise additional components, such as one or more other polymers and/or one or more additives. Other polymers may include another ethylene/α -olefin interpolymer, a polyester, a post-consumer or post-industrial recycled polymer, 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 additional polymer may be up to 50 weight percent based on the total weight of the second region. For example, in embodiments, the second region may comprise up to 50 weight percent of a propylene-based plastomer or propylene-based elastomer (such as VERSIFY available from dow chemical company) ^TM Polymers and VISTAMAXX available from exxonmobil chemical company ^TM Polymer), low modulus or/and low molecular weight polypropylene (such as L-MODU from light extraction) ^TM Polymers), random copolymerized propylene or propylene-based olefin block copolymers (such as INTUNE) ^TM ). Potential additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, antiblocking agents, slip agents, adhesion promoters, flame retardants, antimicrobial agents, deodorants, antifungal agents, and combinations thereof. The second region may contain additives in a combined weight of about 0.01 or 0.1 or 1 to about 25 or about 20 or about 15 or about 10 or about 5 weight percent, based on the total weight of the second region.

In embodiments, the first ethylene/a-olefin interpolymer has a maximum peak melting temperature (Tm) of less than 130 ℃, and the first ethylene/a-olefin interpolymer has a maximum peak melting temperature (Tm) at least 3.5 ℃ greater than the maximum peak melting temperature (Tm) of the second ethylene/a-olefin interpolymer, wherein the maximum peak melting temperature (Tm) can be measured according to the DSC test method described below. All individual values and subranges from at least 3.5 ℃ are disclosed and included herein. For example, in some embodiments, the highest peak melting temperature (Tm) of the first ethylene/a-olefin interpolymer is at least 3.5 ℃ greater, at least 4.0 ℃ greater, at least 4.5 ℃ greater, or at least 5 ℃ greater than the highest peak melting temperature (Tm) of the second ethylene/a-olefin interpolymer. In other embodiments, the difference between the highest peak melting temperature (Tm) of the first ethylene/a-olefin interpolymer and the highest peak melting temperature (Tm) of the second ethylene/a-olefin interpolymer is in the range of 3.5 ℃ to 60 ℃, 4.0 ℃ to 60 ℃, 4.5 ℃ to 60 ℃,5 ℃ to 60 ℃, 3.5 ℃ to 45 ℃, 4.0 ℃ to 45 ℃,5 ℃ to 45 ℃, 3.5 ℃ to 30 ℃, 4.0 ℃ to 30 ℃, 4.5 ℃ to 30 ℃,5 ℃ to 30 ℃, 3.5 ℃ to 15 ℃, 4.0 ℃ to 15 ℃, 4.5 ℃ to 15 ℃, or 5 ℃ to 15 ℃, wherein the highest peak melting temperature (Tm) can be measured according to the DSC test method described below.

In embodiments, the second ethylene/a-olefin interpolymer has a maximum peak melting temperature (Tm) of less than 127.5 ℃ when measured according to the DSC test method described below. All individual values and subranges from less than 127.5 ℃ are disclosed and incorporated herein. For example, in embodiments, the highest peak melting temperature (Tm) of the second ethylene/a-olefin interpolymer can be less than 127 ℃, less than 126.5 ℃, less than 126 ℃, less than 125.5 ℃, less than 125 ℃, less than 124 ℃, less than 123.5 ℃, or less than 123 ℃ or can be in the range of 90 ℃ to 127.5 ℃, 100 ℃ to 127.5 ℃, 110 ℃ to 127.5 ℃, 120 ℃ to 127.5 ℃, 122 ℃ to 127.5 ℃, 90 ℃ to 126 ℃, 100 ℃ to 126 ℃, 110 ℃ to 126 ℃, 120 ℃ to 126 ℃, 122 ℃ to 126 ℃, 90 ℃ to 124 ℃, 100 ℃ to 124 ℃, 110 ℃ to 124 ℃, 120 ℃ to 124 ℃, or 122 ℃ to 124 ℃, where the highest peak melting temperature (Tm) can be measured according to the DSC test method described below.

In embodiments, the maximum peak crystallization temperature (Tc) of the second ethylene/a-olefin interpolymer is in the range of from 90 ℃ to 114.5 ℃, wherein the maximum peak crystallization temperature (Tc) can be measured according to the DSC test method described below. All individual values and subranges from 90 ℃ to 114.5 ℃ are disclosed and included herein. For example, the highest peak crystallization temperature (Tc) of the second ethylene/a-olefin interpolymer can be in the range of 90 ℃ to 114.5 ℃, 90 ℃ to 110 ℃, 90 ℃ to 105 ℃, 95 ℃ to 100 ℃, 95 ℃ to 110 ℃, 95 ℃ to 105 ℃, or 95 ℃ to 100 ℃, 90 ℃ to 114 ℃, 90 ℃ to 113 ℃, or 90 ℃ to 112 ℃, wherein the highest peak crystallization temperature (Tc) can be measured according to the DSC test method described below.

In embodiments, the highest peak crystallization temperature (Tc) of the first ethylene/α -olefin interpolymer is at least 3.5 ℃ greater than the highest peak crystallization temperature (Tc) of the second ethylene/α -olefin interpolymer. All individual values and subranges from at least 3.5 ℃ greater are included herein and disclosed herein. For example, the highest peak crystallization temperature (Tc) of the first ethylene/α -olefin interpolymer can be at least 3.5 ℃ greater, at least 5 ℃ greater, at least 7.5 ℃ greater, at least 10 ℃ greater, at least 11 ℃ greater, at least 15 ℃ greater, or at least 17 ℃ greater than the highest peak crystallization temperature (Tc) of the second ethylene/α -olefin interpolymer, wherein the highest peak crystallization temperature (Tc) can be measured according to the DSC test method described below. In other embodiments, the difference between the highest peak crystallization temperature (Tc) of the first ethylene/a-olefin interpolymer and the highest peak crystallization temperature (Tc) of the second ethylene/a-olefin interpolymer is in the range of from 3.5 ℃ to 25 ℃,5 ℃ to 25 ℃, 10 ℃ to 25 ℃,15 ℃ to 25 ℃, 3.5 ℃ to 20 ℃,5 ℃ to 20 ℃, 10 ℃ to 20 ℃,15 ℃ to 20 ℃, 3.5 ℃ to 15 ℃,5 ℃ to 15 ℃, or 10 ℃ to 15 ℃, wherein the highest peak crystallization temperature (Tc) can be measured according to the DSC test method described below.

Synthesis of first or second ethylene/alpha-olefin interpolymers

Any conventional polymerization process can be used to produce the first or second ethylene/a-olefin interpolymer. Such conventional polymerization processes include, but are not limited to, solution polymerization processes using one or more conventional reactors (e.g., loop reactors in parallel, series, isothermal reactors, stirred tank reactors, batch reactors, and/or any combination thereof). Such conventional polymerization processes also include gas phase, solution or slurry polymerizations or any combination thereof using any type of reactor or reactor configuration known in the art.

In embodiments, the solution phase polymerization process occurs at a temperature in the range of 115 ℃ to 250 ℃ in one or more well-stirred reactors, such as one or more loop reactors; for example at a temperature in the range of 155 ℃ to 225 ℃ and at a pressure in the range of 300 to 1000 psi; for example, at pressures of 400psi to 750 psi. In one embodiment, in a dual reactor, the temperature in the first reactor temperature is in the range of 115 ℃ to 190 ℃ (e.g., 115 ℃ to 170 ℃), and the second reactor temperature is in the range of 150 ℃ to 210 ℃ (e.g., 170 ℃ to 205 ℃). In another embodiment, in a single reactor, the temperature in the reactor temperature is in the range of 115 ℃ to 250 ℃ (e.g., 155 ℃ to 225 ℃). The residence time during solution phase polymerization is typically in the range of 2 minutes to 30 minutes; for example, in the range of 5 minutes to 20 minutes. Ethylene, solvent, one or more catalyst systems, optionally one or more co-catalysts, optionally one or more impurity scavengers, and optionally one or more comonomers are continuously fed to one or more reactors. Exemplary solvents include, but are not limited to, isoparaffins. For example, such solvents are commercially available under the name ISOPAR E from exxonmobil chemical, houston, texas. The resulting mixture of the first or second polyethylene composition and the solvent is then withdrawn from the reactor and the first or second polyethylene composition is separated. The solvent is typically recovered via a solvent recovery unit (i.e., a heat exchanger and a vapor liquid separator drum) and then recycled back into the polymerization system.

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

An example of a catalyst system suitable for producing the first ethylene/a-olefin interpolymer may be a catalyst system comprising a primary catalyst component comprising a metal-ligand complex of formula (I):

in formula (I), M is a metal selected from titanium, zirconium or hafnium, the formal oxidation state of the metal being +2, +3 or +4; n is 0, 1 or 2; when n is 1, X is a monodentate ligand or a bidentate ligand; when n is 2, each X is a monodentate ligand and is the same or different; the metal-ligand complex is electrically neutral as a whole; each Z is independently selected from-O-, -S-, -N (R) ^N ) -or-P (R) ^P ) -, wherein each R ^N And R ^P Independently is a (C1-C30) hydrocarbyl or (C1-C30) heterohydrocarbyl; l is (C) ₁ -C ₄₀ ) Alkylene or (C) ₁ -C ₄₀ ) A heterohydrocarbylene group of which (C) ₁ -C ₄₀ ) Alkylene has a moiety (L is bonded to) comprising a linker backbone linking the 1-carbon atom to the 10-carbon atom of the two Z groups in formula (I), or (C) ₁ -C ₄₀ ) The heterohydrocarbylene group has a moiety comprising a 1-atom to 10-atom linker backbone linking two Z groups in formula (I), wherein (C) ₁ -C ₄₀ ) 1-atom to 10-atom of the Heterohydrocarbylene radical each of the 1 to 10 atoms connecting the backbone is independently a carbon atom or a heteroatom, wherein each heteroatom is independently O, S, S (O), S (O) ₂ 、Si(R ^C ) ₂ 、Ge(R ^C ) ₂ 、P(R ^C ) Or N (R) ^C ) Wherein each R is ^C Independently is (C) ₁ -C ₃₀ ) Hydrocarbyl or (C) ₁ -C ₃₀ ) A heterohydrocarbyl group; r ¹ And R ⁸ Independently selected from the group consisting of: -H, (C) ₁ -C ₄₀ ) Hydrocarbyl radical, (C) ₁ -C ₄₀ ) Heterohydrocarbyl, -Si (R) ^C ) ₃ 、-Ge(R ^C ) ₃ 、-P(R ^P ) ₂ 、-N(R ^N ) ₂ 、-OR ^C 、-SR ^C 、-NO ₂ 、-CN、-CF ₃ 、R ^C S(O)-、R ^C S(O) ₂ -、(R ^C ) ₂ C＝N-、R ^C C(O)O-、R ^C OC(O)-、R ^C C(O)N(R ^N )-、(R ^N ) ₂ NC (O) -, halogen and groups of formula (II), (III) or (IV):

in the formulae (II), (III) and (IV), R ^31-35 、R ^41-48 Or R ^51-59 Each of (A) is independently selected from (C) ₁ -C ₄₀ ) Hydrocarbyl, (C) ₁ -C ₄₀ ) Heterohydrocarbyl, -Si (R) ^C ) ₃ 、-Ge(R ^C ) ₃ 、-P(R ^P ) ₂ 、-N(R ^N ) ₂ 、-N＝CHR ^C 、-OR ^C 、-SR ^C 、-NO ₂ 、-CN、-CF ₃ 、R ^C S(O)-、R ^C S(O) ₂ -、(R ^C ) ₂ C＝N-、R ^C C(O)O-、R ^C OC(O)-、R ^C C(O)N(R ^N )-、(R ^N ) ₂ NC (O) -, halogen or-H, with the proviso that R ¹ Or R ⁸ At least one of which is a group of formula (II), formula (III) or formula (IV), wherein R ^C 、R ^N And R ^P As defined above.

In the formula (I), R ^2-4 、R ^5-7 And R ^9-16 Each of (A) is independently selected from (C) ₁ -C ₄₀ ) Hydrocarbyl radical, (C) ₁ -C ₄₀ ) Heterohydrocarbyl, -Si (R) ^C ) ₃ 、-Ge(R ^C ) ₃ 、-P(R ^P ) ₂ 、-N(R ^N ) ₂ 、-N＝CHR ^C 、-OR ^C 、-SR ^C 、-NO ₂ 、-CN、-CF ₃ 、R ^C S(O)-、R ^C S(O) ₂ -、(R ^C ) ₂ C＝N-、R ^C C(O)O-、R ^C OC(O)-、R ^C C(O)N(R ^N )-、(R ^C ) ₂ NC (O) -, halogen and-H, wherein R ^C 、R ^N And R ^P As defined above.

The catalyst system comprising the metal-ligand complex of formula (I) may be rendered catalytically active by any technique known in the art for activating metal-based catalysts for olefin polymerization reactions. For example, the metal-ligand complex of formula (I) can be rendered catalytically active by contacting the complex with an activating cocatalyst or by combining the complex with an activating cocatalyst. Activating cocatalysts suitable for use herein include aluminum alkyls; polymeric or oligomeric aluminoxanes (also known as aluminoxanes); a neutral lewis acid; and non-polymeric, non-coordinating, ion-forming compounds (including the use of such compounds under oxidizing conditions). A suitable activation technique is bulk electrolysis. Combinations of one or more of the foregoing activating cocatalysts and techniques are also contemplated. The term "alkylaluminum" means monoalkylaluminum dihydride or monoalkylaluminum dihalide, dialkylaluminum hydride or dialkylaluminum halide, or trialkylaluminum. Examples of the polymeric or oligomeric aluminoxane include methylaluminoxane, methylaluminoxane modified with triisobutylaluminum, and isobutylaluminoxane.

Lewis acid activators (cocatalysts) include compounds containing 1 to 3 of (C) as described herein ₁ -C ₂₀ ) A hydrocarbyl-substituted group 13 metal compound. An example of the group 13 metal compound is tris ((C) ₁ -C ₂₀ ) Hydrocarbyl-substituted aluminum or tris ((C) ₁ -C ₂₀ ) Hydrocarbyl) -boron compounds; tri (hydrocarbyl) substituted aluminum, tri ((C) ₁ -C ₂₀ ) Hydrocarbyl) -boron compounds; three ((C) ₁ -C ₁₀ ) Alkyl) aluminum, tris ((C) ₆ -C ₁₈ ) Aryl) boron compounds; and halogenated (including perhalogenated) derivatives thereof. In further examples, the group 13 metal compound is tris (fluoro-substituted phenyl) borane, tris (penta) boraneFluorophenyl) borane. The activating cocatalyst can be tri ((C) ₁ -C ₂₀ ) Hydrocarbyl borates (e.g. trityl tetrafluoroborate) or tris ((C) ₁ -C ₂₀ ) Hydrocarbyl-tetra ((C) ₁ -C ₂₀ ) Hydrocarbyl) ammonium borolidates (e.g., bis (octadecyl) methyltetrakis (pentafluorophenyl) borane). As used herein, the term "ammonium" means a nitrogen cation which is ((C) ₁ -C ₂₀ ) Alkyl radical) ₄ N ⁺ 、((C ₁ -C ₂₀ ) Alkyl radical) ₃ N(H) ⁺ 、((C ₁ -C ₂₀ ) Alkyl radical) ₂ N(H) ₂ ⁺ 、(C ₁ -C ₂₀ ) Alkyl radicals N (H) ₃ ⁺ Or N (H) ₄ ⁺ Wherein two or more (C) are present ₁ -C ₂₀ ) When the hydrocarbon groups are present, they may be the same or different.

Combinations of neutral lewis acid activators (cocatalysts) include mixtures comprising: three ((C) ₁ -C ₄ ) Alkyl) aluminum and tris ((C) halide ₆ -C ₁₈ ) Aryl) boron compounds, especially combinations of tris (pentafluorophenyl) borane; or a combination of such a mixture of neutral lewis acids with a polymeric or oligomeric aluminoxane, as well as a combination of a single neutral lewis acid, especially tris (pentafluorophenyl) borane, with a polymeric or oligomeric aluminoxane. (Metal-ligand Complex) (Tris (pentafluoro-phenylborane): aluminoxane) [ e.g., (group 4 metal-ligand Complex): tris (pentafluoro-phenylborane): aluminoxane]1 to 1, or 1.

The catalyst system comprising the metal-ligand complex of formula (I) can be activated to form an active catalyst composition by combination with one or more cocatalysts (e.g., a cation forming cocatalyst, a strong lewis acid, or a combination thereof). Suitable activating cocatalysts include polymeric or oligomeric aluminoxanes, especially methylaluminoxane, as well as inert, compatible, noncoordinating, ion forming compounds. Exemplary suitable cocatalysts include, but are not limited to, modified Methylaluminoxane (MMAO), bis (hydrogenated tallow alkyl) methyltetrakis (pentafluorophenyl) borate (1) ^- ) Amines and combinations thereof.

The foregoing activitiesOne or more of the promoting cocatalysts may be used in combination with each other. A preferred combination is tris ((C) ₁ -C ₄ ) Hydrocarbyl aluminum, tris ((C) ₁ -C ₄ ) Hydrocarbyl) borane or ammonium borate with oligomeric or polymeric aluminoxane compounds. The ratio of the total moles of the one or more metal-ligand complexes of formula (I) to the total moles of the one or more of the activating cocatalysts is from 1. The ratio may be at least 1; and may not exceed 10. When aluminoxane is used alone as the activating cocatalyst, the number of moles of aluminoxane employed may preferably be at least 100 times the number of moles of the metal-ligand complex of formula (I). When tris (pentafluorophenyl) borane is used alone as the activation co-catalyst, the ratio of moles of tris (pentafluorophenyl) borane employed to the total moles of the one or more metal-ligand complexes of formula (I) can be 0.5 to 10. The remainder of the activating cocatalyst is generally employed in a molar amount approximately equal to the total molar amount of the one or more metal-ligand complexes of formula (I).

Nonwoven fabric

Disclosed herein are nonwovens formed from the bicomponent fibers described above.

The nonwoven formed from the bicomponent fibers disclosed herein may be formed via different techniques. Such techniques for forming nonwovens from bicomponent fibers disclosed herein include melt spinning, melt blowing processes, spunbonding processes, stapling processes, carding web processes, air laying processes (air laid processes), hot calendaring processes, adhesive bonding processes, hot air bonding processes, needling processes, hydroentangling processes, and electrospinning processes. For example, in one embodiment, a spunbond nonwoven comprising bicomponent fibers according to embodiments disclosed herein may be formed. In other embodiments, meltblown nonwovens may be formed comprising bicomponent fibers according to embodiments disclosed herein.

The nonwoven formed from the bicomponent fibers disclosed herein may have lower denier, enhanced tensile strength, enhanced abrasion resistance, and/or higher elongation at breakCombinations of (a) and (b). In one or more embodiments herein, the nonwoven may exhibit one or more of the following properties: a fiber denier of equal to or less than 1.5g/9000m (alternatively, equal to or less than 1.4g/9000m, equal to or less than 1.3g/9000m, or equal to or less than 1.2g/9000m, or in the range of 0.8g/9000m to 2g/9000m, 1.0g/9000m to 1.8g/9000m, 1.0g/9000m to 1.6g/9000m, or 1.0g/9000m to 1.4g/9000 m), wherein the fiber denier is measured according to the test method described below; a tensile strength in the Machine Direction (MD) of greater than 11.0 newtons per inch (N/1 inch) (alternatively, greater than 13.0N/1 inch, greater than 15.0N/1 inch, or greater than 17.0N/1 inch, or in the range of 12.0N/1 inch to 25N/1 inch, 13.0N/1 inch to 25N/1 inch, 15.0N/1 inch to 25N/1 inch, or 18.0N/1 inch to 25N/1 inch) under 20 grams per square meter (gsm) of nonwoven, wherein the tensile strength is measured according to the test method described below; less than 0.18mg/cm in the Machine Direction (MD) under 20gsm nonwoven ² (alternatively, less than 0.16 mg/cm) ² Less than 0.14mg/cm ² Less than 0.12mg/cm ² Less than 0.10mg/cm ² Less than 0.08mg/cm ² Less than 0.06mg/cm ² Or at 0.01mg/cm ² To 0.16mg/cm ² 、0.01mg/cm ² To 0.12mg/cm ² Or 0.01mg/cm ² To 0.06mg/cm ² Within the ranges of (a) and (b), wherein the abrasion resistance is measured according to the test method described below; and an elongation at break (%) in the Machine Direction (MD) of greater than 100% (alternatively, greater than 120%, greater than 140%, greater than 160%, or in the range of 110% to 200%, 120% to 200%, 140% to 200%, or 160% to 200%) at 20gsm of the nonwoven, wherein the elongation at break is measured according to the test method described below.

For example, a nonwoven according to embodiments disclosed herein may have a tensile strength greater than 11.0N/1 inch in the Machine Direction (MD) at 20gsm of the nonwoven, and an elongation at break (%) greater than 100% in the Machine Direction (MD) at 20gsm of the nonwoven. As another example, a nonwoven according to embodiments disclosed herein may have a caliper in the Machine Direction (MD) of greater than 20gsm nonwovenA tensile strength of 11.0N/1 inch, and less than 0.18mg/cm in the Machine Direction (MD) at 20gsm nonwoven ² The wear resistance of (2). As yet another example, a nonwoven according to embodiments disclosed herein may have a tensile strength in the Machine Direction (MD) of greater than 11.0N/1 inch at 20gsm of nonwoven; an elongation at break (%) greater than 100% in the Machine Direction (MD) at 20gsm nonwoven; and less than 0.18mg/cm in the Machine Direction (MD) at 20gsm of nonwoven ² The wear resistance of (2).

Nonwovens formed from the bicomponent fibers disclosed herein are on an elution curve achieved via an Improved Comonomer Composition Distribution (ICCD) procedure at 40.0 ℃ to 68.0 ℃ (WT _40℃-68℃ ) Can comprise at least 12 wt% of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer combined at a temperature range of from 40.0 ℃ to 68.0 ℃ on an elution curve achieved via ICCD can be measured according to the test method described below. All individual values and subranges from at least 12 weight percent are disclosed and included herein. For example, the nonwoven is on the elution curve achieved via the modified comonomer composition distribution (ICCD) procedure at 40.0 ℃ to 68.0 ℃ (WT) _40℃-68℃ ) Can comprise at least 12 wt%, at least 14 wt%, at least 18 wt%, at least 22 wt%, at least 26 wt%, or at least 28 wt% of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer in combination, wherein the weight percent at a temperature range of from 40.0 ℃ to 68.0 ℃ on an elution curve achieved via ICCD can be measured according to the test method described below.

Nonwovens formed from the bicomponent fibers disclosed herein are on an elution profile achieved via an Improved Comonomer Composition Distribution (ICCD) procedure at 40.0 ℃ to 65.0 ℃ (WT) _40℃-65℃ ) Can comprise at least 6 wt% of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer combined at a temperature range of from 40.0 ℃ to 65.0 ℃ on an elution curve achieved via ICCD can be measured according to the test method described below. Disclosed herein and including at least 6% by weightAll individual values and subranges. For example, the nonwoven is on the elution curve achieved via the modified comonomer composition distribution (ICCD) procedure at 40.0 ℃ to 65.0 ℃ (WT) _40℃-65℃ ) Can comprise at least 6 wt%, at least 8 wt%, at least 12 wt%, at least 16 wt%, at least 20 wt%, or at least 22 wt% of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer in combination, wherein the weight percent at a temperature range of from 40.0 ℃ to 65.0 ℃ on an elution curve achieved via ICCD can be measured according to the test method described below.

Nonwovens formed from the bicomponent fibers disclosed herein are on an elution profile achieved via an Improved Comonomer Composition Distribution (ICCD) procedure at 40.0 ℃ to 60.0 ℃ (WT) _40℃-60℃ ) Can comprise at least 2 wt% of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer combined at a temperature range of from 40.0 ℃ to 60.0 ℃ on an elution curve achieved via ICCD, wherein the weight percent can be measured according to the test method described below. All individual values and subranges from at least 2 weight percent are disclosed herein and included herein. For example, the nonwoven was on an elution curve achieved via an Improved Comonomer Composition Distribution (ICCD) procedure at 40.0 ℃ to 60.0 ℃ (WT) _40℃-60℃ ) Can comprise at least 2 wt%, at least 4 wt%, at least 6 wt%, at least 8 wt%, at least 10 wt%, or at least 11 wt% of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer in combination, wherein the weight percent at a temperature range of from 40.0 ℃ to 60.0 ℃ on an elution curve achieved via ICCD can be measured according to the test method described below.

Test method

Density of

Density is measured according to ASTM D-792 and in grams/cm ³ (g/cm ³ ) And (4) showing.

Melt index (I2)

Melt index (I2) can be measured according to ASTM D1238 at 190 degrees celsius and 2.16kg and is expressed in grams eluted per 10 minutes (g/10 min).

Conventional gel permeation chromatography (conventional GPC)

The chromatographic system consisted of a PolymerChar GPC-IR (spain, valencia) high temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR 5). The autosampler oven chamber was set at 160 ℃ and the column chamber was set at 150 ℃. The column used was a 4-Angelen "Mixed A"30cm 20 micron linear mixed bed column. The chromatographic solvent used was 1,2,4-trichlorobenzene and contained 200ppm of Butylated Hydroxytoluene (BHT). The solvent source was nitrogen sparged. The injection volume used was 200 microliters, and the flow rate was 1.0 milliliters/minute.

Calibration of the GPC column set was performed with at least 20 narrow molecular weight distribution polystyrene standards with molecular weights in the range 580 to 8,400,000g/mol, and arranged in 6 "cocktail" mixtures with at least ten times the separation between individual molecular weights. These standards were purchased from Agilent Technologies, inc. For molecular weights equal to or greater than 1,000,000g/mol, polystyrene standards were prepared at 0.025 grams in 50 milliliters of solvent, and for molecular weights less than 1,000,000g/mol, polystyrene standards were prepared at 0.05 grams in 50 milliliters of solvent. The polystyrene standards were dissolved by gentle stirring at 80 ℃ for 30 minutes. The peak polystyrene standard molecular weight was converted to the ethylene/α -olefin interpolymer molecular weight using the following equation (as described by Williams and Ward in journal of polymer science (j.polymer.sci.), (polymer article.), (6, 621 (1968)):

M _polyethylene ＝A×(M _Polyethylene ) ^B (equation 1)

Where M is molecular weight, A has a value of 0.4315, and B is equal to 1.0.

A fifth order polynomial was used to fit the corresponding ethylene/a-olefin interpolymer-equivalent calibration points. A small adjustment was made to a (from about 0.39 to 0.44) to correct for column resolution and band broadening effects, resulting in NIST standard NBS 1475 at a molecular weight of 52,000g/mol.

The total plate count of the GPC column set was performed with eicosane (prepared at 0.04g in 50ml TCB and dissolved for 20 minutes with gentle stirring). Plate count (eq. 2) and symmetry (eq. 3) were measured at 200 microliter injection according to the following equations:

where RV is the retention volume in milliliters, the Peak width is in milliliters, the Peak maximum (Peak Max) is the maximum height of the Peak, and the half height is half the height of the Peak maximum.

Wherein RV is the retention volume in milliliters and the peak width is in milliliters, the peak maximum is the maximum position of the peak, the height of one tenth is one tenth of the height of the peak maximum, and wherein the posterior peak refers to the tail of the peak at the retention volume later than the peak maximum, and wherein the anterior peak refers to the front of the peak at the retention volume earlier than the peak maximum. The plate count of the chromatography system should be greater than 22,000 and the symmetry should be between 0.98 and 1.22.

The samples were prepared in a semi-automated manner using PolymerChar "instrument control" software, with the target weight of the sample set at 2mg/ml, and the solvent (containing 200ppm BHT) was added via a PolymerChar high temperature autosampler to a pre-nitrogen sparged vial covered with a septum. The sample was dissolved at 160 ℃ for 3 hours under "slow" shaking.

M _n(GPC) 、M _w(GPC) And M _z(GPC) Is based on GPC results using an internal IR5 detector (measurement channel) of a polymerChar GPC-IR chromatograph according to equations 5a-5c, using a polymerChar GPCOne ^TM Software, baseline subtracted IR chromatograms (IR) at each equidistant data collection point i _i ) And an ethylene/alpha-olefin interpolymer equivalent molecular weight (M in g/mol) obtained from a narrow standard calibration curve at point i according to equation 1 _{Polyethylene, i} )。Subsequently, a GPC molecular weight distribution (GPC-MWD) chart (wt) can be obtained _GPC (lgMW) vs. lgMW, where wt _GPC (lgMW) is the weight fraction of interpolymer molecules having a molecular weight of lgMW). Molecular weight in g/mol, and wt _GPC (lgMW) follows equation 4.

∫wt _GPC (lg MW) d lg MW =1.00 (Eq.4)

Number average molecular weight M _n(GPC) Weight average molecular weight M _w(GPC) And z average molecular weight M _z(GPC) Can be calculated as follows.

To monitor the time-varying deviation, 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 (nominal)) for each sample by comparing the RV of the corresponding decane peak within the sample (RV (FM sample)) to the RV of the decane peak within the narrow standard calibration (RV (calibrated by FM)). It was then assumed that any change in the decane marker peak time correlated with a linear change in flow rate (effective) throughout the run. To facilitate the highest accuracy of RV measurements of the flow marker peak, a least squares fitting procedure is used to fit the peak of the flow marker concentration chromatogram to a quadratic equation. The first derivative of the quadratic equation is then used to solve for the true peak position. After calibrating the system based on the flow marker peak, the effective flow rate (calibrated against narrow standards) is calculated as in equation 6. Flow marker peak treatment via PolymerChar GPCOne ^TM And (4) completing software. Acceptable flow rate correction is such that the effective flow rate should be at nominalWithin 0.5% of the flow rate.

Flow rate of flow _{Is effective} Flow rate _{Nominal scale} ×(RV(FM _Calibration )/RV(FM _{Sample (I)} ) (equation 6)

Improved Comonomer Composition Distribution (ICCD)

The modified comonomer composition distribution (ICCD) test was performed with a crystal elution fractionation instrument (CEF) (pely morch, spain) equipped with an IR-5 detector (pely morch, spain) and a two-angle light scattering detector model 2040 (precision detector, currently available from agilent technologies). ICCD column A15 cm (length). Times.1/4' (ID) stainless steel tube was filled with gold-plated nickel particles (Bright 7GNM8-NiS, nippon Chemical Industrial Co., ltd.). Column packing and conditioning were performed with a slurry method according to the reference (Cong, R.; parrott, A.; hollis, C.; cheatham, M.WO2017040127A1, which is incorporated herein by reference). The final pressure of the Trichlorobenzene (TCB) slurry fill was 150 bar. The column was installed just before the IR-5 detector in the detector oven. Ortho-dichlorobenzene (ODCB, 99% anhydrous or technical) was used as eluent. Silica gel 40 (particle size 0.2mm to 0.5mm, catalog number 10181-3) was obtained from EMD Chemicals and may be used to dry ODCB solvents. ICCD instrument was equipped with nitrogen (N) ₂ ) Automatic sampler of function sweeps. ODCB uses dry N prior to use ₂ Bubbling for one hour. Sample preparation was performed with an autosampler at 4mg/ml (unless otherwise indicated) at 160 ℃ for 1 hour with shaking. The injection volume was 300. Mu.l. The temperature profile of the ICCD is: crystallization from 105 ℃ to 30 ℃ at 3 ℃/min followed by thermal equilibration at 30 ℃ for 2 minutes (including soluble fraction elution time set to 2 minutes) followed by heating from 30 ℃ to 140 ℃ at 3 ℃/min. The flow rate during elution was 0.50ml/min. Data was collected at one data point per second. Column temperature calibration can be achieved by using a reference material, linear homopolymer polyethylene (with zero comonomer content, melt index (I) ₂ ) 1.0g/10min, polydispersity M _w(GPC) /M _n(GPC) Measured by conventional gel permeation chromatography about 2.6,1.0 mg/ml) and eicosane (b)2 mg/ml) in ODCB. The ICCD temperature calibration consists of four steps: (1) Calculating a delay volume defined as the measured eicosane peak elution temperature minus the temperature shift between 30.00 ℃; (2) The temperature offset of the elution temperature was subtracted from the ICCD raw temperature data (note that this temperature offset varies with experimental conditions such as elution temperature, elution flow rate, etc.); (3) Creating a linear calibration line, switching elution temperatures in the range of 30.00 ℃ and 140.00 ℃ such that the linear homopolymer polyethylene reference has a peak temperature at 101.0 ℃ and eicosane has a peak temperature at 30.0 ℃; and (4) for the soluble fraction measured isothermally at 30 ℃, the elution temperature below 30.0 ℃ was linearly extrapolated by using an elution heating rate of 3 ℃/min according to the reference (Cerk and Cong et al, US9,688,795, which is incorporated herein by reference).

Weight percent determination on ICCD elution Curve

A single baseline is subtracted from the IR measurement signal in order to create a relative mass-elution profile that starts and ends with zero relative mass at its lowest and highest elution temperatures (typically between 35 ℃ and 119 ℃). For convenience, this is expressed as a normalized quantity with respect to the total area equal to 1. In the relative mass-elution plot from ICCD, the weight fraction (w) at each temperature (T) can be obtained _T (T)) (this weight fraction can be converted to a weight percentage). Curve (w) _T (T) vs. T) is from 35.0 ℃ to 119.0 ℃ in the presence of a 0.200 ℃ temperature step increase in ICCD and is as follows:

weight fraction (WT) _{Lower T-higher T} ) Can be determined by aligning w over the temperature range of interest according to the following equation _T (T) integrate the T curve to calculate:

tensile strength and% elongation at break test method

For tensile testing, 20 grams per square meter (gsm) of nonwoven was cut in the Machine Direction (MD) into 1 inch x 8 inch rectangular strips for tensile testing using an Instron tensile tester. Initial chuck-to-chuck distance (L) at 76.2mm ₀ ) The strips were then tested at a test speed of 300 mm/min. The tensile strength of the nonwoven was measured in newtons per 1 inch (N per 1 inch width) at peak force. At peak load, the chuck-to-chuck distance (L) was read and the elongation at break (%) was reported as (L-L) ₀ )/L ₀ X 100%. The average of 5 samples is reported.

Abrasion resistance test method

The abrasion resistance of the exemplary nonwoven can be measured using a Sutherland ink rub tester. Prior to testing, samples of 20gsm nonwoven were cut into 12.5cm by 5cm rectangular strips and conditioned at 73F. +/-2 and constant relative humidity for at least four hours. A rectangular strip of 12.5cm x 5cm of 320 grit alumina cloth sandpaper was then mounted on a Sutherland ink rub tester. The sample was then weighed to the nearest 0.01mg and mounted on the tester. A 2 pound weight was then attached to the Sutherland ink rub tester and the tester was run for 20 cycles at a rate of 42 cycles per minute. Loose fibers were removed using adhesive tape and the sample was reweighed to determine the amount of material lost. Abrasion resistance is defined as the amount of material loss weight divided by the size of the abraded area. Abrasion resistance in mg/cm ² . The average of 5 samples is reported.

Fiber denier measurement

Fiber diameter was measured via optical microscopy. Denier (defined as the weight of such fiber at 9000 meters) is calculated based on the density and fiber diameter of each polymer component.

Determination of filament speed

The filament speed is calculated based on the following equation:

filament speed (meters/minute) = throughput (g/min)/denier (g/9000 m) × 9,000 (equation 9).

Differential Scanning Calorimetry (DSC)

Differential scanning calorimetry was used to measure the highest peak melting temperature (Tm) and highest peak crystallization temperature (Tc) according to ASTM D3895-14. Approximately 0.5 grams of the sample was compression molded into a film at 25,000psi and 190 degrees celsius for 10 seconds to 15 seconds. Weigh 5mg to 8mg of sample and place the sample in a DSC aluminum pan with the lid crimped onto the pan to ensure a closed atmosphere. During the test, a nitrogen purge stream of 50ml/min was used.

The thermal characteristics of the sample are determined by ramping the sample temperature up and down to produce a heat flow versus temperature curve. For cooling and second heating information, the sample was heated to 150 degrees celsius at a rate of 10 degrees celsius/min and isothermally held for 5 minutes. The sample was then cooled to-40 degrees celsius at a rate of 10 degrees celsius/min, isothermally held for 5 minutes, and then heated to 150 degrees celsius at a rate of 10 degrees celsius/min.

The cooling curve and the second heating curve were recorded. The cooling curve was analyzed by setting the baseline end point from the start of crystallization to-20 ℃. The heating curve was analyzed by setting a baseline end point from-20 ℃ to the end of melting. The values determined are the highest peak melting temperature (Tm) and the highest peak crystallization temperature (Tc). The highest peak melting temperature (Tm) is reported according to the second heating curve. The highest peak crystallization temperature (Tc) is determined from the cooling curve.

Examples

Production example of ethylene/alpha-olefin interpolymer

Polymer 1 (poly.1), polymer 2 (poly.2), and polymer 3 (poly.3), which are ethylene/a-olefin interpolymers, were prepared according to the following procedures and tables.

All of the feed (monomer and comonomer) and process solvents (narrow boiling range high purity isoparaffin solvent, isopar-E) were purified using molecular sieves prior to introduction into the reaction environment. Hydrogen is supplied pressurized at high purity levels and without further purification. The reactor monomer feed stream is pressurized via a mechanical compressor to greater than the reaction pressure. The solvent and comonomer (if present) feeds are pressurized via pumps to above the reaction pressure. The various catalyst components were manually diluted in batches with the purification solvent and pressurized above the reaction pressure. All reaction feed streams were measured with mass flow meters and independently controlled with a computer automated valve control system.

The reactor configuration was either single reactor operation or dual series reactor operation as specified in tables 2A and 2B below.

A single reactor system or a dual reactor system in a series configuration is used. Each 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 (if present), hydrogen and catalyst component feeds can be independently controlled. The temperature of the total fresh feed stream (solvent, monomer, comonomer if present and hydrogen) to each reactor is typically controlled between 15 ℃ and 50 ℃ by passing the feed streams through a heat exchanger to maintain a single solution phase. The total fresh feed to each polymerization reactor was injected into the reactor at two locations with approximately equal reactor volumes between each injection location. Fresh feed was controlled by having each injector receive half of the total fresh feed mass flow. Catalyst components are injected into the polymerization reactor through an injection nozzle to introduce the components into the center of the reactor stream. The main catalyst component feed was computer controlled to maintain the reactor monomer conversion at the specified value. The co-catalyst component is fed based on the 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 static mixing elements. The contents of each reactor are continuously circulated through a heat exchanger responsible for removing most of the heat of reaction, and wherein the temperature of the coolant side is responsible for maintaining the isothermal reaction environment at the specified temperature. Circulation around each reactor loop is provided by a pump.

In a dual series reactor configuration, the effluent from the first polymerization reactor (containing solvent, monomer, comonomer if present, hydrogen, catalyst components, and polymer) exits the first reactor loop and is added to the second reactor loop. In all reactor configurations, the final reactor effluent (either the second reactor effluent in a double series or the single reactor effluent) enters a zone where a suitable reagent (water) is added and reacted with to deactivate the final reactor effluent. At this same reactor exit location, other additives were added for polymer stabilization (e.g., antioxidants suitable for stabilization during extrusion and manufacture, including octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, tetrakis (methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)) methane, and tris (2,4-di-tert-butyl-phenyl) phosphite).

After catalyst deactivation and addition of additives, the reactor effluent enters a devolatilization system where the polymer is removed from the non-polymer stream. The separated polymer melt was pelletized and collected. The non-polymer stream is passed through various devices that separate most of the ethylene removed from the system. Most of the solvent and unreacted comonomer (if present) is recycled back to the reactor after passing through the purification system. Small amounts of solvent and comonomer (if present) are purged from the process.

Fig. 1 and 2 graphically depict reactor stream feed data streams corresponding to the values in tables 2A and 2B for polymer production. The data are presented so that the complexity of the solvent recycling system is taken into account and the reaction system can be handled more simply as an once-through flow diagram (once through flow diagram).

TABLE 1 catalyst Components

Table 2A-Poly.3 production configuration

Table 2B production configurations of Poly.1 and Poly.2

The following ethylene/α -olefin interpolymers are also used in the examples.

Polymer 4 (Poly.4) is ASPUN ^TM 6850A, an ethylene/α -olefin interpolymer commercially available from Dow chemical company (Midland, mich.).

Polymer 5 (Poly.5) is ASPUN ^TM 6835A, an ethylene/α -olefin interpolymer commercially available from dow chemical company (midland, michigan).

Polymer 6 (Poly.6) is ASPUN ^TM 6000, an ethylene/α -olefin interpolymer commercially available from dow chemical company (midland, michigan).

Polymer 7 (Poly.7) is DOWLEX ^TM 2517, an ethylene/α -olefin interpolymer commercially available from dow chemical company (midland, michigan).

Polymer 8 (Poly.8) is ELITE ^TM 5860, ethylene/α -olefin interpolymer commercially available from Dow chemical company (Midland, mich.).

Table 3 below provides the melt index (I2), density, mw for Poly.1 to Poly 8 _(GPC) /Mn _(GPC) A maximum peak crystallization temperature (Tc), and a maximum peak melting temperature (Tm).

TABLE 3 Properties of Poly.1 to Poly.8

Fiber and nonwoven formation

The spunbond nonwoven was formed from bicomponent fibers and was produced on a single strand Reicofil 4 spunbond line in a 50 (in weight percent) concentric core to sheath configuration. The core of the bicomponent fiber was an ethylene/alpha olefin interpolymer composition as reported in table 4. The sheath is the same or different ethylene/alpha olefin interpolymer composition as reported in table 4. The machine (Reicofil 4 spunbond line) was equipped with a spinneret with 7022 holes (6861 holes/m) and the exit diameter of each hole was 0.6mm. The L/D ratio of the wells was 4. The polymer melt temperature was set at about 230 ℃. The fibers were collected at maximum sustainable cabin air pressure while maintaining stable fiber spinning and converting the fibers to a target basis weight of 20gsm nonwoven. The web bonding was performed between the engraved roll and smooth roll at a nip pressure of 70 daN/cm. The oil temperature of the engraved roll was adjusted to achieve optimal bonding without over wrapping the nonwoven onto the roll. The oil temperature of the smooth roll was maintained 2 c below the oil temperature of the engraved roll.

Example nonwovens formed from bicomponent fibers have been designated as inventive examples and comparative examples, as reported in table 4. The fiber denier of the nonwoven, as well as the difference in peak maximum melting temperature (Δ Tm), peak maximum crystallization temperature (Δ Tc), and density (Δ density) between the first and second regions of the bicomponent fiber are reported in table 5.

The first ethylene/α -olefin interpolymer and the second ethylene/α -olefin interpolymer combined on the ICCD elution curve of the nonwoven fabric examples are reported in table 6 at 40.0 ℃ to 68.0 ℃ (WT) WT ₄₀ ℃ _-68 40.0 ℃ to 65.0 ℃ (WT DEG C), 40.0 ℃ to 65.0 ℃ (WT DEG C) ₄₀ ℃ _-65 40.0 ℃ to 60.0 ℃ (WT DEG C) and ₄₀ ℃ _-60 c) temperature range in percent by weight (% by weight). Referring now generally to FIG. 3, the nonwoven of the present invention is shownICCD elution profile of example 2. The combined weight percentages of Poly.3 and Poly.8 of example 2 of this invention were 40.0 deg.C to 68.0 deg.C (WT) on the ICCD elution curve ₄₀ ℃ _-68 C) is equal to 30% (as reported in table 6). The two polymers of each region of the inventive nonwovens (inventive example 1 and inventive example 2) have a higher weight percentage on the ICCD elution curve, which contributes to enhanced abrasion resistance, tensile strength, and/or elongation at break properties (without being bound by theory).

Additional treatment conditions for the nonwovens are reported in table 7. Additional properties of the nonwoven are shown in table 8. Compared to comparative nonwovens (comparative examples 1-8), the inventive nonwovens (inventive example 1 and inventive example 2) have fine fiber denier while having higher Δ Tm, Δ Tc, and Δ density, which contributes to enhanced abrasion resistance, tensile strength, and/or elongation at break properties (without being bound by theory).

TABLE 4 composition of bicomponent fibers used to form nonwovens

TABLE 5 denier, Δ Density, Δ Tc and Δ Tm data

TABLE 6 ICCD data for nonwoven examples

TABLE 7 useUnder additional conditions for forming nonwovens

Table 8-properties of the nonwovens: reported in newtons per inch (N/1 inch) in the Machine Direction (MD) at 20gsm ² The tensile strength of (d); abrasion resistance reported in mg/cm at 20gsm in MD; and elongation at break in MD at 20gsm The growth rate is percent.

Each document cited herein (if any), including any cross-referenced or related patents or applications and any patent applications or patents to which this application claims priority or benefit, is hereby incorporated by reference in its entirety herein, unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it teaches, teaches or discloses any such invention alone or in combination with any one or more other references. In addition, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

1. A bicomponent fiber, comprising:

a first region and a second region;

the first region comprises a first ethylene/a-olefin interpolymer having a highest peak melting temperature (Tm) less than 130 ℃ when measured by DSC;

the second region comprises a second ethylene/a-olefin interpolymer having a density less than the density of the first ethylene/a-olefin interpolymer composition;

wherein the highest peak melting temperature (Tm) of the first ethylene/a-olefin interpolymer is at least 3.5 ℃ greater than the highest peak melting temperature (Tm) of the second ethylene/a-olefin interpolymer, wherein the highest peak melting temperature (Tm) is measured by DSC;

wherein the first region and the second region are arranged in a core-sheath configuration.

2. The bicomponent fiber of claim 1, wherein the first ethylene/a-olefin interpolymer has a highest peak crystallization temperature (Tc) that is at least 3.5 ℃ greater than the highest peak crystallization temperature (Tc) of the second ethylene/a-olefin interpolymer, wherein highest peak crystallization temperature (Tc) is measured by DSC.

3. The bicomponent fiber of claims 1-2, wherein the density of the first ethylene/a-olefin interpolymer is at least 0.022g/cm greater than the density of the second ethylene/a-olefin interpolymer ³ 。

4. A nonwoven formed from the bicomponent fiber of claims 1-3, wherein the nonwoven has one or more of the following properties: a fiber denier equal to or less than 1.5g/9000 m; a tensile strength in the machine direction of greater than 11.0 newtons per inch at 20gsm of the nonwoven; an elongation to break in the machine direction of greater than 100% at 20gsm of the nonwoven; and less than 0.18mg/cm in the machine direction under 20gsm of the nonwoven ² Wear resistance of (2).

5. A nonwoven formed from bicomponent fibers according to claims 1 to 3A woven fabric, wherein the nonwoven fabric is on an elution curve achieved via an Improved Comonomer Composition Distribution (ICCD) procedure from 40.0 ℃ to 68.0 ℃ (WT _40℃-68℃ ) Comprises at least 12 wt% of the first ethylene/a-olefin interpolymer and the second ethylene/a-olefin interpolymer combined.

6. A nonwoven formed from the bicomponent fiber of claims 1-3, wherein the nonwoven has a fiber denier equal to or less than 1.5g/9000 m; a tensile strength in the machine direction of greater than 11.0 newtons per inch at 20gsm of the nonwoven; an elongation to break in the machine direction of greater than 100% at 20gsm of the nonwoven; and less than 0.18mg/cm in the machine direction under 20gsm of the nonwoven ² Wear resistance of (2).