WO2021226246A1 - Fibres à deux composants présentant une courbure améliorée - Google Patents

Fibres à deux composants présentant une courbure améliorée Download PDF

Info

Publication number
WO2021226246A1
WO2021226246A1 PCT/US2021/030904 US2021030904W WO2021226246A1 WO 2021226246 A1 WO2021226246 A1 WO 2021226246A1 US 2021030904 W US2021030904 W US 2021030904W WO 2021226246 A1 WO2021226246 A1 WO 2021226246A1
Authority
WO
WIPO (PCT)
Prior art keywords
polyethylene composition
region
centroid
fiber
molecular weight
Prior art date
Application number
PCT/US2021/030904
Other languages
English (en)
Inventor
Akanksha GARG
Yijian Lin
Aleksandar Stoiljkovic
Jozef J. I. Van Dun
Fabricio ARTEAGA LARIOS
Rajesh P. PARADKAR
Original Assignee
Dow Global Technologies Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dow Global Technologies Llc filed Critical Dow Global Technologies Llc
Priority to US17/997,615 priority Critical patent/US20230272567A1/en
Priority to JP2022564105A priority patent/JP2023524202A/ja
Priority to KR1020227042285A priority patent/KR20230009911A/ko
Priority to EP21728706.9A priority patent/EP4146853A1/fr
Priority to BR112022022436A priority patent/BR112022022436A2/pt
Priority to CN202180033534.2A priority patent/CN115516144A/zh
Publication of WO2021226246A1 publication Critical patent/WO2021226246A1/fr

Links

Classifications

    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
    • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
    • D01F8/06—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyolefin as constituent
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/28—Formation of filaments, threads, or the like while mixing different spinning solutions or melts during the spinning operation; Spinnerette packs therefor
    • D01D5/30—Conjugate filaments; Spinnerette packs therefor
    • D01D5/34—Core-skin structure; Spinnerette packs therefor
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
    • D04H3/005—Synthetic yarns or filaments
    • D04H3/007—Addition polymers
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
    • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
    • D04H3/14—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic yarns or filaments produced by welding
    • D04H3/147—Composite yarns or filaments
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
    • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
    • D04H3/16—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2321/00—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D10B2321/02—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins
    • D10B2321/021—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins polyethylene

Definitions

  • Embodiments of the present disclosure generally relate to bicomponent fibers with improved curvature that comprise polyethylene, and nonwovens comprising the fibers.
  • Bicomponent fibers are fibers made of two different polymer compositions that are extruded from the same spinneret with both compositions contained within the same filament or fiber. When the fiber leaves the spinneret, it consists of non-mixed components that are fused at the interface.
  • the two polymer compositions can differ in their chemical and/or physical properties.
  • Bicomponent fibers can be formed by conventional spinning techniques known in the art and can be used for forming a nonwoven. Nonwoven fabrics have numerous applications, such as filters, disposable materials in medical applications, and diaperstock. To assist in reducing nonwoven weight or obtaining other advantageous nonwoven properties, such as loft, bicomponent fibers having curvature can be used. However, problems exist with obtaining bicomponent fibers with improved curvature and with maintaining or improving other advantageous properties, such as spinnability, softness, recyclability, and extensibility, while improving curvature.
  • Embodiments of the present disclosure provide bicomponent fibers that can be used to form nonwovens and that provide in aspects unique and surprisingly high curvature, while also maintaining or improving other properties such as spinnability, tactile softness, recyclability, and extensibility.
  • Bicomponent fibers according to embodiments of the present disclosure each include a first region and a second region comprising a first polyethylene composition and a second polyethylene composition, respectively, that contribute to a fiber with improved curvature and advantageous spinnability, softness, recyclability, and extensibility.
  • bicomponent fibers according to embodiments of the present disclosure comprise a first polyethylene composition and a second polyethylene composition that can improve spinnability, softness, recyclability, and extensibility, and can interface to improve the inherent curvature of the fibers (e.g., fiber curvature that is not the result of mechanical crimping or a post-extrusion process, such as attenuation with heated air or application of tension).
  • 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 a first polyethylene composition having a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (M W (GPC)/M n (GPC)), of less than 3.0; the second region comprising a second polyethylene composition having a density less than a density of the first polyethylene composition; wherein at least one of the first centroid and the second centroid is not the same as the fiber centroid; and wherein the first polyethylene composition has a crystallization temperature (Tc) at least 2°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • Tc crystallization temperature
  • 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 a first polyethylene composition having a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (Mw(GPC)/M n (GPC)), of greater than 3.0; the second region comprising a second polyethylene composition having a density less than a density of the first polyethylene composition; wherein at least one of the first centroid and the second centroid is not the same as the fiber centroid; wherein the first polyethylene composition has a crystallization temperature (Tc) at least 3.5°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • Tc crystallization temperature
  • a spunbond nonwoven can be formed from the bicomponent fiber disclosed herein.
  • the spunbond nonwoven comprises a bicomponent fiber comprising a fiber centroid; a first region having a first centroid and a second region having a second centroid; the first region comprising a first polyethylene composition having a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (M W (GPC)/M n (GPC)), of less than 3.0; the second region comprising a second polyethylene composition having a density less than a density of the first polyethylene composition; wherein at least one of the first centroid and the second centroid is not the same as the fiber centroid; and wherein the first polyethylene composition has a crystallization temperature (Tc) at least 2°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • Tc crystallization temperature
  • the spunbond nonwoven comprises a bicomponent fiber comprising a fiber centroid; a first region having a first centroid and a second region having a second centroid; the first region comprising a first polyethylene composition having a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (M W (GPC)/M n (GPC)), of greater than 3.0; the second region comprising a second polyethylene composition having a density less than a density of the first polyethylene composition; wherein at least one of the first centroid and the second centroid is not the same as the fiber centroid; wherein the first polyethylene composition has a crystallization temperature (Tc) at least 3.5°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • Tc crystallization temperature
  • FIG. 1 is a scanning electron micrograph (SEM) cross-section image of a bicomponent fiber having an eccentric core-sheath configuration and centroid off-set.
  • FIG. 2 is an illustration of a single reactor stream feed data flow used to produce a polyethylene composition disclosed herein.
  • FIG. 3 is an illustration of a dual reactor stream feed data flow used to produce a polyethylene composition disclosed herein.
  • bicomponent fibers having increased curvature can be used to form nonwovens, and such nonwovens can have a wide variety of applications, including, for example, wipes, face masks, tissues, bandages, and other medical and hygiene products. It is noted however, that this is merely an illustrative implementation of the embodiments disclosed herein. The embodiments are applicable to other technologies that are susceptible to similar problems as those discussed above.
  • 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.
  • the term, “consisting essentially of’ excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability.
  • the term “consisting of’ excludes any component, step or procedure not specifically delineated or listed.
  • interpolymer refers to polymers prepared by the polymerization of at least two different types of monomers.
  • the term interpolymer thus includes copolymers (employed to refer to polymers prepared from two different types of monomers), and polymers prepared from more than two different types of monomers.
  • polymer means a polymeric compound prepared by polymerizing monomers, whether of the same or a different type.
  • the generic term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure), and the term interpolymer. Trace amounts of impurities (for example, catalyst residues) may be incorporated into and/or within the polymer.
  • a polymer may be a single polymer or polymer blend.
  • polyethylene composition refers to a polymer comprising greater than 50% by weight of units which are derived from ethylene monomer, and optionally, one or more comonomers.
  • a polyethylene composition includes polyethylene homopolymers, copolymers, or interpolymers.
  • LDPE Low Density Polyethylene
  • LLDPE Linear Low Density Polyethylene
  • ULDPE Ultra Low Density Polyethylene
  • VLDPE Very Low Density Polyethylene
  • m-LLDPE linear low density resins
  • MDPE Medium Density Polyethylene
  • HDPE High Density Polyethylene
  • nonwoven refers to a web or fabric having a structure of individual fibers or threads which are randomly interlaid, but not in an identifiable manner as is the case for a knitted fabric.
  • meltblown refers to the fabrication of a nonwoven fabric via a process which includes the following steps: (a) extruding molten thermoplastic strands from a spinneret; (b) simultaneously quenching and attenuating the polymer stream immediately below the spinneret using streams of high velocity heated air; (c) collecting the drawn strands into a web on a collecting surface.
  • Meltblown nonwoven webs can be bonded by a variety of means including, but not limited to, autogeneous bonding (i.e., self bonding without further treatment), thermo-calendaring process, adhesive bonding process, hot air bonding process, needle punch process, hydroentangling process, and combinations thereof.
  • the term “spunbond” refers to the fabrication of a nonwoven fabric including the following steps: (a) extruding molten thermoplastic strands from a plurality of fine capillaries called a spinneret; (b) quenching the strands of the thermoplastic strands comprising, for example, a polyethylene composition, with a flow of air which is generally cooled in order to hasten the solidification of the molten strands of the thermoplastic; (c) attenuating the filaments by advancing them through the quench zone with a draw tension that can be applied by either pneumatically entraining the filaments in an air stream or by winding them around mechanical draw rolls of the type commonly used in the textile fibers industry; (d) collecting the drawn strands into a web on a foraminous surface (e.g., moving screen or porous belt); and (e) bonding the web of loose strands into the nonwoven fabric.
  • a foraminous surface e.g., moving screen or porous belt
  • Bonding can be achieved by a variety of means including, but not limited to, thermo-calendaring process, adhesive bonding process, hot air bonding process, needle punch process, hydroentangling process, and combinations thereof.
  • curvature refers to the curve or crimp of an individual fiber that is result of its composition and not the result of any post-extrusion process that can impact the curve or crimp of the fiber (e.g., mechanical crimping or attenuation by heat).
  • the amount of curvature of the bicomponent fibers disclosed herein can be measured in accordance with the test method described below.
  • the fibers taught herein may be formed by any conventional spinning technique.
  • the first region and the second region of a bicomponent fiber can be formed into a fiber via melt spinning.
  • melt spinning the first region comprising a first polyethylene composition and second region comprising a second polyethylene composition can be melted, coextruded, and forced through the fine orifices in a metallic plate, called a spinneret, into air or other gas, where they are cooled and solidified forming a bicomponent fiber.
  • the solidified fiber may be drawn off via air jets, rotating rolls, or godets, and can be laid on a conveyer belt as a web for forming a nonwoven.
  • a meltblown nonwoven comprising a bicomponent fiber according to embodiments of the present disclosure can be formed.
  • a spunbond nonwoven comprising a bicomponent fiber according to embodiments of the present disclosure can be formed.
  • the fibers disclosed herein have improved curvature and advantageous other properties, such as recyclability, tactile softness, and extensibility as a result of being comprised of polyethylene.
  • the improved curvature of the fibers disclosed herein is not the result of mechanical crimping or a post-extrusion process, such as attenuation with heated air or application of tension.
  • the fibers in aspects include all or a majority polyethylene compositions. Nonwovens comprising polyethylene compositions are known for their tactile softness, and materials comprising polyethylene compositions are candidates for compatibility with polyethylene recycling streams.
  • the bicomponent fiber has a curvature of at least 0.50 mm 1 .
  • the curvature of the bicomponent fiber can be measured in accordance with the test method described below. All individual values and subranges of at least 0.50 mm 1 are disclosed and included herein.
  • the bicomponent fiber can have a curvature of at least 0.50, 0.60, 0.70, or 0.80 mm 1 , when measured according to the test method described below.
  • the bicomponent fiber can have a curvature in the range of from 0.50 to 3.00, from 0.50 to 2.50, from 0.50 to 2.00, from 0.50 to 1.50, from 0.50 to 1.00, from 1.00 to 3.00, from 1.00 to 2.50, from 1.00 to 2.00, from 1.00 to 1.50, from 1.50 to 3.00, from 1.50 to 2.50, from 1.50 to 2.00, from 2.00 to 3.00, or from 2.00 to 2.50 mm 1 , when measured according to the test method described below.
  • the bicomponent fiber comprises a first region and a second region, wherein the weight ratio of the first region to the second region is 90:10 to 10:90. All individual values and subranges of a ratio of from 90:10 to 10:90 are disclosed and included herein.
  • the weight ratio of the first region to the second region can be 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.
  • the fibers taught herein are bicomponent fibers, a person of ordinary skill in the art will appreciate that because the two regions of the fibers both contain polyethylene compositions, it may not be readily discernable from the fiber itself that it includes two different regions.
  • Raman microscopy and multivariate calibration can be used to measure, in situ, the percent (%) crystallinity of individual polyethylene regions of the bicomponent fibers. The difference between the Raman measured % crystallinity of the two regions of the bicomponent fibers according to embodiments of the present disclosure corresponds to the improved curvature of the fibers.
  • the first polyethylene composition of the first region of the bicomponent fiber has a Raman measured % crystallinity at least 5.0 % greater than a Raman measured % crystallinity of the second polyethylene composition of the second region of the bicomponent fiber, where Raman measured % crystallinity is measured in accordance with the test method described below.
  • the first polyethylene composition of the first region of the bicomponent fiber can have a Raman measured % crystallinity at least 5.0% greater than, at least 7.5% greater than, at least 10.0% greater than, or from 5.0% to 20.0% greater than, from 5.0% to 15.0% greater than, from 7.5% to 15.0% greater than, from 10.0% to 15.0% greater than, from 3.5% to 12.0% greater than, from 5.0% to 12.0% greater than, from 7.5% to 12.0% greater than, or from 10.0% to 12.0% greater than a Raman measured % crystallinity of the second polyethylene composition of the second region of the bicomponent fiber, where Raman measured % crystallinity is measured in accordance with the test method described below.
  • the 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 not the same as the fiber centroid.
  • centroid refers to the arithmetic mean of all the points of a region of a cross-section of a bicomponent fiber.
  • the bicomponent fiber according to embodiments of the present disclosure has a fiber centroid, which can be designated as C f
  • a region of the bicomponent fiber e.g., the first or second region
  • C rx a region of the bicomponent fiber
  • x is a designation of the region (e.g., the first region can be designated as C ri and the second region can be designated as C r2 )
  • r is the average distance from C f to the outer surface of the bicomponent fiber and is calculated as - A/p, where A is the area of the bicomponent fiber cross-section.
  • Fig. 1 illustrates a bicomponent fiber and its centroid as well as the centroid of the second region of the bicomponent fiber.
  • the distance from a region centroid to the fiber centroid can be defined as “P rx ”, and the centroid offset of the first centroid or second centroid to the fiber centroid can be defined as “P rx /r.”
  • the bicomponent fiber can have different configurations, such as eccentric core sheath, side-by-side, or segmented pie, but cannot have a concentric configuration (e.g., a core sheath concentric configuration) where the fiber centroid, first centroid, and the second centroid are the same.
  • the first centroid of the first region and the second centroid of the second region are arranged such that the first region and the second region are in a side-by-side configuration.
  • first centroid of the first region and the second centroid of the second region are arranged such that the first region and the second region are in a segmented pie configuration. In further embodiments, the first centroid of the first region and the second centroid of the second region are arranged such that the first region and the second region are in an eccentric core-sheath configuration, where 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.
  • the first centroid or the second centroid is offset from the fiber centroid by at least 0.1, or at least 0.2, or at least 0.4, and is less than 1 or less than 0.9, where offset is measured in accordance with the test method described below.
  • the bicomponent fiber comprises a first region and a second region; the first region comprises a first polyethylene composition having a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (M W (GPC)/M n (GPC)), of less than 3.0; the second region comprises a second polyethylene composition having a density less than a density of the first polyethylene composition; wherein the first polyethylene composition has a crystallization temperature (Tc) at least 2°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • the first polyethylene composition can be formed in the presence of a metallocene or single site catalyst.
  • the first polyethylene composition has a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (M W (GPC)/M n (GPC)), of less than 3.0.
  • the first polyethylene composition has a molecular weight distribution (M W (GPC)/M n (GPC)) of less than 3.0, less than 2.8, less than 2.6, less than 2.4, or less than 2.2, or from a range of from 1.8 to 3.0, 1.8 to 2.6, 1.8 to 2.4, 1.8 to 2.2, 2.0 to 3.0, 2.0 to 2.6, 2.0 to 2.4, 2.0 to 2.2, 2.2 to 2.6, or 2.2 to 2.4, where molecular weight distribution can be expressed as the ratio of the weight average molecular weight to number average molecular weight (M W (GPC)/M n (GPC)) and can be measured in accordance with the test method described below.
  • the first polyethylene composition has a crystallization temperature (Tc) at least 2°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • Tc crystallization temperature
  • All individual values and subranges of a crystallization temperature (Tc) of the first polyethylene composition at least 2°C greater than a crystallization temperature (Tc) of the second polyethylene composition are disclosed and included herein; for example, the first polyethylene composition can have a crystallization temperature (Tc) of at least 2°C greater than, at least 4°C greater than, at least 6°C greater than, at least 8°C greater than, at least 10°C greater than, at least 12°C greater than, at least 14°C greater than, at least 16°C greater than, or at least 18°C greater than a crystallization temperature (Tc) of the second polyethylene composition, or the difference between a crystallization temperature (Tc) of the first polyethylene composition minus a crystallization temperature (Tc) of the second polyethylene composition can be
  • the first polyethylene composition can have a melting temperature (Tm) at least 2°C greater than a melting temperature (Tm) of the second polyethylene composition.
  • Tm melting temperature
  • Tm melting temperature
  • All individual values and subranges of a melting temperature (Tm) of the first polyethylene composition at least 2°C greater than a melting temperature (Tm) of the second polyethylene composition are disclosed and included herein; for example, the first polyethylene composition can have melting temperature (Tm) of at least 2°C greater than, at least 4°C greater than, at least 6°C greater than, at least 8°C greater than, at least 10°C greater than, at least 14°C greater than, at least 18°C greater than, at least 22°C greater than, or at least 26°C greater than, or at least 30 °C greater than a melting temperature (Tm) of the second polyethylene composition, or the difference between a melting temperature (Tm) of the first polyethylene composition minus a melting temperature (Tm) of the second polyethylene composition can be in the range
  • the melting temperature (Tm) of the first polyethylene composition can be less than 130°C. All individual values and subranges of less than 130°C are disclosed and included herein; for example, the melting temperature (Tm) of the first polyethylene composition can be less than 130°C, less than 129.8°C, less than 129.6°C, less than 129.4°C, less than 129.2°C, less than 129°C, or less than 128.9°C, where melting temperature (Tm) can be measured according to DSC as described below. In embodiments, the melting temperature (Tm) of the second polyethylene composition can be less than 127°C.
  • the melting temperature (Tm) of the second polyethylene composition can be less than 127°C, less than 126.5°C, less than 125°C, less than 120°C, less than 115°C, less than 110°C, less than 105°C, less than 100°C, less than 99°C, less than 98.5°C, or less than 98°C, where melting temperature (Tm) can be measured according to DSC as described below.
  • the difference between the melting temperature (Tm) of the first polyethylene composition minus the melting temperature (Tm) of the second polyethylene composition can be at least 1.5°C. All individual values and subranges of at least 1.5°C are included and disclosed herein; for example, the difference between the melting temperature (Tm) of the first polyethylene composition minus the melting temperature (Tm) of the second polyethylene composition can be at least 1.5°C, at least 2.0°C, at least 2.5°C, at least 3°C, at least 5°C, at least 10°C, at least 15°C, at least 20°C, at least 25°C, or at least 30°C, or can be in the range of from 1.5°C to 40°C, 2.0°C to 40°C, 2.5°C to 40°C, 1.5°C to 30°C, 2.0°C to 30°C, 2.5°C to 30°C, 1.5°C to 20°C, 2.0°C to 20°C, 2.5°C to 20°C, 1.5°C to 10°C, 2.0°C
  • the bicomponent fiber comprises a first region and a second region; the first region comprises a first polyethylene composition having a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (M W (GPC)/M I ,(GPC)), of greater than 3.0; the second region comprises a second polyethylene composition having a density less than a density of the first polyethylene composition; wherein the first polyethylene composition has a crystallization temperature (Tc) at least 3.5°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • the first polyethylene composition can be formed in the presence of a Ziegler-Natta catalyst.
  • the first polyethylene composition has a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (M W( GPC)/M n( GPC)), of greater than 3.0. All individual values and subranges of a molecular weight distribution (M W (GPC)/M I ,(GPC)) of greater than 3.0 are disclosed and included herein; for example, in embodiments, the first polyethylene composition has a molecular weight distribution (M W (GPC)/M n (GPC)) of 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 from a range of from 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, where molecular weight
  • the first polyethylene composition has a crystallization temperature (Tc) at least 3.5°C greater than a crystallization temperature (Tc) of the second polyethylene composition.
  • Tc crystallization temperature
  • All individual values and subranges of a crystallization temperature (Tc) of the first polyethylene composition at least 3.5°C greater than a crystallization temperature (Tc) of the second polyethylene composition are disclosed and included herein; for example, the first polyethylene composition can have a crystallization temperature (Tc) of at least 3.5°C greater than, at least 4°C greater than, at least 4.5°C greater than, at least 5°C greater than, at least 5.5°C greater than, at least 6°C greater than, at least 6.2°C greater than, or at least 6.4°C greater than a crystallization temperature (Tc) of the second polyethylene composition, or the difference between a crystallization temperature (Tc) of the first polyethylene composition minus a crystallization temperature (Tc) of the second polyethylene composition can be in
  • the first polyethylene composition can have a melting temperature (Tm) at least 5°C greater than a melting temperature (Tm) of the second polyethylene composition. All individual values and subranges of a melting temperature (Tm) of the first polyethylene composition at least 5°C greater than a melting temperature (Tm) of the second polyethylene composition are disclosed and included herein; for example, the first polyethylene composition can have melting temperature (Tm) of at least 5°C greater than, at least 5.2°C greater than, at least 5.4°C greater than, at least 5.6°C greater than, at least 5.8°C greater than, at least 6.0°C greater than, at least 6.2°C greater than, and at least 6.4°C greater than, at least 6.6°C greater than, at least 6.8°C greater than, or at least 6.9 °C greater than a melting temperature (Tm) of the second polyethylene composition, or the difference between a melting temperature (Tm) of the first polyethylene composition minus a melting temperature (Tm) of the second polyethylene composition,
  • the second polyethylene composition has a density less than a density less than a density of the first polyethylene composition, where density can be measured according to ASTM D792.
  • the density of the first polyethylene composition is at least 0.015 g/cm 3 greater than the density of the second polyethylene composition.
  • the density of the first polyethylene composition is at least 0.015 g/cm 3 , at least 0.030 g/cm 3 , or at least 0.040 g/cm 3 greater than the density of the second polyethylene composition, or the difference between the density of the first polyethylene composition minus the density of the second polyethylene composition is in the range of from 0.015 g/cm 3 to 0.100 g/cm 3 , 0.015 g/cm 3 to 0.080 g/cm 3 , 0.015 g/cm 3 to 0.060 g/cm 3 , 0.015 g/cm 3 to 0.040 g/cm 3 , 0.015 g/cm 3 to 0.020 g/cm 3 , 0.020 g/cm 3 to 0.100 g/cm 3 , 0.020 g/cm 3 to
  • the first polyethylene composition can have a density of at least 0.925 g/cm 3 , where density can be measured according to ASTM D792. All individual values and subranges of a density in the range of at least 0.925 g/cm 3 are disclosed and included herein.
  • the first polyethylene composition can have a density of at least 0.935, at least 0.940, at least 0.945, at least 0.950, at least 0.955, at least 0.960, or at least 0.965 g/cm 3 , where density can be measured according to ASTM D792, or the first polyethylene composition can have a density in the range of from 0.925 to 0.980, from 0.930 to 0.980, from 0.940 to 0.980, from 0.950 to 0.980, from 0.930 to 0.980, from 0.930 to 0.970, from 0.930 to 0.960, from 0.930 to 0.950, from 0.940 to 0.980, from 0.940 to 0.970, from 0.940 to 0.960, from 0.940 to 0.950, from 0.945 to 0.980, from 0.945 to 0.970, from 0.945 to 0.960, from 0.945 to 0.955, from 0.950 to 0.980, from 0.950 to 0.970, from 0.950 to 0.960, from 0.950 to 0.960, from
  • the first region of the bicomponent fiber comprises at least 75 wt.% of the first polyethylene composition. All individual values and subranges of at least 75 wt.% are included and disclosed herein; for example, the first region can comprise at least 75 wt.%, at least 80 wt.%, at least 85 wt.%, at least 90 wt.%, at least 95 wt.%, or from 75 wt.% to 100 wt.%, from 75 wt.% to 90 wt.%, from 75 wt.% to 80 wt.%, from 80 wt.% to 100 wt.%, or from 90 wt.% to 100 wt.%, of the first polyethylene composition, where weight percent is based on the total weight of the first region.
  • the second region of the bicomponent fiber comprises at least 75 wt.% of the second polyethylene composition. All individual values and subranges of at least 75 wt.% are included and disclosed herein; for example, the second region can comprise at least 75 wt.%, at least 80 wt.%, at least 85 wt.%, at least 90 wt.%, at least 95 wt.%, or from 75 wt.% to 100 wt.%, from 75 wt.% to 90 wt.%, from 75 wt.% to 80 wt.%, from 80 wt.% to 100 wt.%, or from 90 wt.% to 100 wt.%, of the second polyethylene composition, where weight percent is based on the total weight of the second region.
  • the first region and/or the second region can comprise additional components, such as, one or more other polymers and/or one or more additives.
  • Other polymers can include a polyester, another polyethylene composition, a propylene-based polymer (e.g. polypropylene homopolymer, propylene-ethylene copolymer, or propylene/alpha-olefin interpolymer), or a propylene-based plastomer or elastomer.
  • the amount of the other polymer may be up to 25 wt.% based on the total weight of the first region or second region including such other polymers.
  • the first region and/or second region can comprise up to 25 wt.% of a propylene-based plastomer or propylene- based elastomer (such as VERSIFYTM polymers available from The Dow Chemical Company and VISTAMAXXTM polymers available from ExxonMobil Chemical Co.), low modulus and/or low molecular weight polypropylene (such as L-MODUTM polymer from Idemitsu), random copolypropylene, or propylene-based olefin block copolymers (such as Intune).
  • a propylene-based plastomer or propylene- based elastomer such as VERSIFYTM polymers available from The Dow Chemical Company and VISTAMAXXTM polymers available from ExxonMobil Chemical Co.
  • low modulus and/or low molecular weight polypropylene such as L-MODUTM polymer from Idemitsu
  • random copolypropylene or propylene-based olefin block cop
  • Potential additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, anti-blocks, slip agents, tackifiers, fire retardants, anti -microbial agents, odor reducer agents, anti-fungal agents, and combinations thereof.
  • the first region and/or second region can contain from about 0.01 or 0.1 or 1 to about 25 or about 20 or about 15 or about 10 weight percent by the combined weight of such additives, based on the weight of the first region or second region including such additives.
  • Any conventional polymerization processes can be employed to produce the first or second polyethylene composition.
  • Such conventional polymerization processes include, but are not limited to, solution polymerization process, using one or more conventional reactors e.g. loop reactors, isothermal reactors, stirred tank reactors, batch reactors in parallel, series, and/or any combinations thereof.
  • Such conventional polymerization processes also include gas-phase, solution or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art.
  • 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 from 115 to 250 °C; for example, from 155 to 225 °C, and at pressures in the range of from 300 to 1000 psi; for example, from 400 to 750 psi.
  • the temperature in the first reactor temperature is in the range of from 115 to 190 °C, for example, from 115 to 150 °C
  • the second reactor temperature is in the range of 150 to 200 °C, for example, from 170 to 195 °C.
  • the temperature in the reactor temperature is in the range of from 115 to 250 °C, for example, from 155 to 225 °C.
  • the residence time in a solution phase polymerization process is typically in the range of from 2 to 30 minutes; for example, from 10 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 fed continuously to one or more reactors.
  • Exemplary solvents include, but are not limited to, isoparaffins.
  • such solvents are commercially available under the name ISOPAR E from ExxonMobil Chemical Co., Houston, Texas.
  • the first or second polyethylene composition may be produced via a solution polymerization process in a dual reactor system, for example a dual loop reactor system, wherein ethylene and optionally one or more a-olefins are polymerized in the presence of one or more catalyst systems.
  • the first or second polyethylene composition may be produced via a solution polymerization process in a single reactor system, for example 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.
  • the first polyethylene composition is formed in the presence of a metallocene or single site catalyst system. In other embodiments, the first polyethylene composition is formed in the presence of a Ziegler-Natta catalyst system.
  • An example of a catalyst system suitable for producing the second polyethylene composition can be a catalyst system comprising a procatalyst component comprising a metal- ligand complex of formula (I):
  • M is a metal chosen from titanium, zirconium, or hafnium, the metal being in a formal oxidation state of +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 overall charge-neutral; each Z is independently chosen from -0-, — S — , — N(R N ) — , or -P(R p )-, wherein independently each R N and R p is (Cl-C30)hydrocarbyl or (Cl-C30)heterohydrocarbyl; L is (C j -C ⁇ hydrocarbylene or
  • the catalyst system comprising a metal-ligand complex of formula (I) may be rendered catalytically active by any technique known in the art for activating metal-based catalysts of olefin polymerization reactions.
  • a metal-ligand complex of formula (I) may be rendered catalytically active by contacting the complex to, or combining the complex with, an activating co-catalyst.
  • Suitable activating co-catalysts for use herein include alkyl aluminums; polymeric or oligomeric alumoxanes (also known as aluminoxanes); neutral Lewis acids; and non-polymeric, non-coordinating, ion-forming compounds (including the use of such compounds under oxidizing conditions).
  • alkyl aluminum means a monoalkyl aluminum dihydride or monoalkylaluminum dihalide, a dialkyl aluminum hydride or dialkyl aluminum halide, or a trialkylaluminum.
  • Examples of polymeric or oligomeric alumoxanes include methylalumoxane, triisobutylaluminum-modified methylalumoxane, and isobutylalumoxane.
  • Lewis acid activators include Group 13 metal compounds containing from 1 to 3 (Ci-C2o)hydrocarbyl substituents as described herein.
  • Group 13 metal compounds are tri((Ci-C2o)hydrocarbyl)-substituted-aluminum or tri((Ci-C2o)hydrocarbyl)- boron compounds; tri(hydrocarbyl)-substituted-aluminum, tri((Ci-C2o)hydrocarbyl)-boron compounds; tri((Ci-Cio)alkyl)aluminum, tri((C 6 -Ci 8 )aryl)boron compounds; and halogenated (including perhalogenated) derivatives thereof.
  • Group 13 metal compounds are tris(fluoro-substituted phenyl)boranes, tris(pentafluorophenyl)borane.
  • An activating co-catalyst can be a tris((Ci-C2o)hydrocarbyl borate (e.g. trityl tetrafluoroborate) or a tri((Ci-C2o)hydrocarbyl)ammonium tetra((Ci-C2o)hydrocarbyl)borane (e.g. bis(octadecyl)methylammonium tetrakis(pentafluorophenyl)borane).
  • ammonium means a nitrogen cation that is a ((Ci-C2o)hydrocarbyl)4N + , a ((Ci- C2o)hydrocarbyl)3N(H) + , a ((Ci-C2o)hydrocarbyl)2N(H)2 + , (Ci-C2o)hydrocarbylN(H)3 + , or N(H)4 + , wherein each (Ci-C2o)hydrocarbyl, when two or more are present, may be the same or different.
  • Combinations of neutral Lewis acid activators include mixtures comprising a combination of a tri((Ci-C4)alkyl)aluminum and a halogenated tri((C 6 -Ci 8 )aryl)boron compound, especially a tris(pentafluorophenyl)borane; or combinations of such neutral Lewis acid mixtures with a polymeric or oligomeric alumoxane, and combinations of a single neutral Lewis acid, especially tris(pentafluorophenyl)borane with a polymeric or oligomeric alumoxane.
  • Ratios of numbers of moles of (metal-ligand complex): (tris(pentafluoro-phenylborane): (alumoxane) are from 1:1:1 to 1:10:30, or from 1:1:1.5 to 1:5:10.
  • 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 co-catalysts, for example, a cation forming co-catalyst, a strong Lewis acid, or combinations thereof.
  • co-catalysts for example, a cation forming co-catalyst, a strong Lewis acid, or combinations thereof.
  • Suitable activating co-catalysts include polymeric or oligomeric aluminoxanes, especially methyl aluminoxane, as well as inert, compatible, noncoordinating, ion forming compounds.
  • Suitable co-catalysts include, but are not limited to: modified methyl aluminoxane (MMAO), bis (hydrogenated tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate(l _ ) amine, and combinations thereof.
  • MMAO modified methyl aluminoxane
  • bis (hydrogenated tallow alkyl)methyl bis (hydrogenated tallow alkyl)methyl
  • tetrakis(pentafluorophenyl)borate(l _ ) amine and combinations thereof.
  • One or more of the foregoing activating co-catalysts can be used in combination with each other.
  • One preferred combination is a mixture of a tri((Ci-C4)hydrocarbyl)aluminum, tri((Ci-C4)hydrocarbyl)borane, or an ammonium borate with an oligomeric or polymeric alumoxane compound.
  • the ratio of total number of moles of one or more metal-ligand complexes of formula (I) to total number of moles of one or more of the activating co-catalysts is from 1:10,000 to 100:1.
  • the ratio can be at least 1:5000, or, at least 1:1000; and can be no more than 10:1 or no more than 1:1.
  • the number of moles of the alumoxane that are employed can be at least 100 times the number of moles of the metal-ligand complex of formula (I).
  • the ratio of the number of moles of the tris(pentafluorophenyl)borane that are employed to the total number of moles of one or more metal-ligand complexes of formula (I) can be from 0.5: 1 to 10:1, from 1:1 to 6:1, or from 1:1 to 5:1.
  • the remaining activating co-catalysts are generally employed in approximately mole quantities equal to the total mole quantities of one or more metal-ligand complexes of formula (I).
  • Density is measured in accordance with ASTM D792, and expressed in grams/cm 3 (g/cm 3 ).
  • the amount of curvature is measured via optical microscopy.
  • the amount of curvature is 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 projection of the helix formed by the fiber on a surface perpendicular to it. Average value of at least 5 measurements is reported. Measurements are reported in units of 1/millimeter (mm 1 ).
  • Fibers were embedded in epoxy and polished under cryogenic conditions using a Leica UCT/FCS microtome operated at -140°C for AFM analysis. Topography and phase images were captured at ambient temperature by using a Bruker Icon AFM system with a MikroMasch probe. The probe has a spring constant of 40 N/m and a resonant frequency in the vicinity of 170 kHz. An imaging frequency of 0.5-2 Hz is used with a set point ratio of approximately 0.8. The diameter of a fiber’s cross section is measured using a single cord, and this measurement is divided in half to mark a mid-point as the fiber centroid (Cf).
  • Cf fiber centroid
  • the core region of the bicomponent fiber is divided with two cords at 90° to visually create four quadrants of equal areas, and the intersection of the two cords defines the centroid of the core region (Cr2).
  • the distance between the fiber centroid (Cf) and the centroid of the core region (Cr2) is measured, and then is divided by the radius of the fiber to calculate the fiber centroid offset (Pr2/r).
  • GPC gel permeation chromatography
  • the IR5 detector (“measurement channel”) is used as a concentration detector.
  • GPCOne software (PolymerChar, Spain) is used to calculate weight-average (Mw), and number- average (Mn) molecular weight of the polymer and to determine molecular weight distribution (Mw/Mn).
  • the method uses three 10 micron PL gel mixed B columns (Agilent Technologies, column dimension 100 X 7.6 mm) or four 20 micron PL gel mixed A columns (Agilent Technologies, column dimension 100 X 7.6 mm) operating at a system temperature of 150 °C.
  • Samples are prepared at a 2 mg/mL concentration in 1,2,4- trichlorobenzene solvent containing 200 part per million of antioxidant butylated hydroxytoluene (BHT) for 3 hours at 160 °C with a gentle shaking by autosampler (PolymerChar, Spain).
  • BHT antioxidant butylated hydroxytoluene
  • the flow rate is 1.0 mL/min, the injection size is 200 microliters.
  • GPCOne software is used to calculate the plate count.
  • the chromatographic system must have a minimum of 22,000 plates.
  • the GPC column set is calibrated by running at least 20 narrow molecular weight distribution polystyrene standards.
  • the calibration uses a third order fit for the system with three 10 micron PL gel mixed B columns or a fifth order fit for the system with four 20 micron PL gel mixed A columns.
  • the molecular weight (MW) of the standards range from 580 g/mol to 8,400,000 g/mol, and the standards are contained in 6 “cocktail” mixtures. Each standard mixture has approximately a decade of separation between individual molecular weights.
  • the standard mixtures are purchased from Agilent Technologies.
  • the polystyrene standards are prepared at “0.025 g in 50 mL of solvent” for molecular weights equal to, or greater than, 1,000,000 g/mol, and at “0.05 g in 50 mL of solvent” for molecular weights less than 1,000,000 g/mol.
  • the polystyrene standards are dissolved at 80°C, with gentle agitation, for 30 minutes.
  • the narrow standards mixtures are run first, and in order of decreasing highest molecular weight component, to minimize degradation.
  • the polystyrene standard peak molecular weights are converted to polyethylene molecular weights using Equation (1) (as described in Williams and Ward, J. Polym. Sci., Polym. Letters, 6, 621 (1968)):
  • MW PE A x (MW ps ) B (Eq. 1) where MW is the molecular weight of polyethylene (PE) or polystyrene (PS) as marked, and B is equal to 1.0. It is known to those of ordinary skill in the art that A may be in a range of about 0.38 to about 0.44 such that the A value yields 52,000 MWPE for Standard Reference Materials (SRM) 1475a.
  • SRM Standard Reference Materials
  • M n,cc , M w,cc , and M z,cc are the number-, weight-, and z-average molecular weight obtained from the conventional calibration, respectively.
  • Wi is the weight fraction of the polyethylene molecules eluted at retention volume Vi.
  • M cc,i is the molecular weight (in g/mole) of the polyethylene molecules eluted at retention volume Vi obtained using the conventional calibration (see Equation (1)).
  • the chromatographic peaks should be set to include area marking a significant visible departure from baseline when the chromatogram is viewed at 20 percent peak height.
  • the baseline should not be integrated to less than 100 polyethylene-equivalent molecular weight and care must be used to account for anti-oxidant mismatch from the prepared sample and the chromatographic mobile phase.
  • w (wt. fraction greater than 10 5 g/mole) is calculated according the MWD curve (wi versus log obtained from GPCOne software according to Equation (5)
  • DSC is used to measure the melting temperature (Tm) and crystallization temperature (Tc) behavior of a polymer over a wide range of temperatures.
  • Tm melting temperature
  • Tc crystallization temperature
  • the TA Instruments Q1000 DSC equipped with an RCS (refrigerated cooling system) and an autosampler is used to perform this analysis.
  • RCS refrigerated cooling system
  • a nitrogen purge gas flow of 50 ml/min is used.
  • Each sample is melt pressed into a thin film at about 175 °C; the melted sample is then air-cooled to room temperature (approx. 25°C).
  • the film sample is formed by pressing a “0.1 to 0.2 gram” sample at 175°C at 1,500 psi, and 30 seconds, to form a “0.1 to 0.2 mil thick” film.
  • a 3-10 mg, 6 mm diameter specimen is extracted from the cooled polymer, weighed, placed in a light aluminum pan (ca 50 mg), and crimped shut. Analysis is then performed to determine its thermal properties.
  • the thermal behavior of the sample is determined by ramping the sample temperature up and down to create a heat flow versus temperature profile. First, the sample is rapidly heated to 180°C, and held isothermal for five minutes, in order to remove its thermal history. Next, the sample is cooled to -40°C, at a 10°C/minute cooling rate, and held isothermal at -40°C for five minutes. The sample is then heated to 150°C (this is the “second heat” ramp) at a 10°C/minute heating rate. The cooling and second heating curves are recorded.
  • the cool curve is analyzed by setting baseline endpoints from the beginning of crystallization to -20°C.
  • the heat curve is analyzed by setting baseline endpoints from -20°C to the end of melt.
  • the heat of fusion (H f ) and the melting temperature (Tm) are reported from the second heat curve.
  • the crystallization temperature (Tc) is determined from the cooling curve.
  • Raman microscopy and multivariate calibration is used to measure the % crystallinity of individual polyethylene regions of the bicomponent fibers, in situ.
  • Raman microscopy a type of vibrational spectroscopic technique, is sensitive to vibrations of the polymer backbone and can provide information on both the amorphous and crystalline phases of a polymer and polyethylene compositions.
  • Raman can use visible or near-infrared radiation and when coupled with an optical microscope provides a lateral spatial resolution of approximately 0.8 to 1.2 micrometers (depending on the excitation laser and microscope objective used).
  • a Partial Least Square (PLS) model is built to correlate Raman data with the annealed base resin density and percent (%) crystallinity calculated from the annealed polyethylene composition density.
  • Annealed density is measured in accordance with ASTM D792. Percent (%) crystallinity is calculated from the measured annealed density using the following equation (Equation 6):
  • Depolarized Raman spectra are acquired using equivalent Thermo Scientific DXR2 micro-Raman instruments. Raman spectra are acquired using a 900 grooves/mm grating. Spectral range covered a Raman shift from 50 to 3500 cm 1 , with a data spacing of 0.964 cm 1 . Other data acquisition parameters are as follows. Acquisition time: 3 - 10 sec; Number of acquisitions: 3 to 6; dark current subtraction, cosmic ray filter and white light correction: turned ON. Calibration data were recorded with an Olympus M PlanN 20x (0.40 NA) objective using a 25 micrometer slit and an Olympus M PlanN lOOx (0.90 NA) objective using a 50 micrometer pinhole.
  • a longitudinal (parallel to the draw direction) cross section of each bicomponent fiber example is prepared.
  • the cross section is oriented on the sample stage such that the draw direction of the fiber is oriented in the East-West direction on the sample stage.
  • Depolarized Raman spectra are acquired in three different locations of each region of the bicomponent fiber example using a lOOx (0.9NA) objective and 25 micrometer pinhole. The resulting Raman spectra from each region are averaged and the average spectrum is used to measure the region % crystallinity using the PLS model.
  • Resin 1 “Resin 2”, “Resin 3”, and “Resin 4” are prepared according to the following process and tables.
  • All raw materials (monomer and comonomer) and the process solvent (a narrow boiling range high-purity isoparaffinic solvent, Isopar-E) are purified with molecular sieves before introduction into the reaction environment. Hydrogen is supplied pressurized as a high purity grade and is not further purified.
  • the reactor monomer feed stream is pressurized via a mechanical compressor to above reaction pressure.
  • the solvent and comonomer (if present) feed is pressurized via a pump to above reaction pressure.
  • the individual catalyst components are manually batch diluted with purified solvent and pressured to above reaction pressure. All reaction feed flows are measured with mass flow meters and independently controlled with computer automated valve control systems.
  • Reactor configuration is either single reactor operation or dual series reactor operation as specified in Table 2.
  • Each reactor is a continuous solution polymerization reactor consisting of a liquid full, non- adiabatic, isothermal, circulating, loop reactor which mimics a continuously stirred tank reactor (CSTR) with heat removal.
  • CSTR continuously stirred tank reactor
  • Independent control of all fresh solvent, monomer, comonomer (if present), hydrogen, and catalyst component feeds is possible.
  • the total fresh feed stream to each reactor (solvent, monomer, comonomer [if present], and hydrogen) is temperature controlled typically between 15-50°C to maintain a single solution phase by passing the feed stream through a heat exchanger.
  • the total fresh feed to each polymerization reactor is injected into the reactor at two locations with approximately equal reactor volumes between each injection location.
  • the fresh feed is controlled with each injector receiving half of the total fresh feed mass flow.
  • the catalyst components are injected into the polymerization reactor through injection nozzles to introduce the components into the center of the reactor flow.
  • the primary catalyst component feed is computer controlled to maintain the reactor monomer conversion at the specified values.
  • the cocatalyst component(s) is/are fed based on calculated specified molar ratios to the primary catalyst component.
  • the feed streams are mixed with the circulating polymerization reactor contents with static mixing elements.
  • the contents of each reactor are continuously circulated through heat exchangers responsible for removing much of the heat of reaction and with the temperature of the coolant side responsible for maintaining an isothermal reaction environment at the specified temperature. Circulation around each reactor loop is provided by a pump. [0076] In 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.
  • the final reactor effluent (second reactor effluent for dual series or the single reactor effluent) enters a zone where it is deactivated with the addition of and reaction with a suitable reagent (water). At this same reactor exit location other additives are added for polymer stabilization.
  • the reactor effluent enters a devolatization system where the polymer is removed from the non-polymer stream.
  • the isolated polymer melt is pelletized and collected.
  • the non-polymer stream passes through various pieces of equipment which separate most of the ethylene which is removed from the system.
  • Most of the solvent and unreacted comonomer (if present) is recycled back to the reactor after passing through a purification system. A small amount of solvent and comonomer (if present) is purged from the process.
  • Table 1 - Catalyst Components 4,612,300 by sequentially adding to a volume of ISOPAR E, a slurry of anhydrous magnesium chloride in ISOPAR E, a solution of EtAlCh in heptane, and a solution of Ti(0-iPr) 4 in heptane, to yield a composition containing a magnesium concentration of 0.20M and a ratio of Mg/Al/Ti of 40/12.5/3. An aliquot of this composition was further diluted with ISOPAR-E to yield a final concentration of 500 ppm Ti in the slurry. An aliquot of this composition can be further diluted with ISOPAR-E if required.
  • the catalyst premix was contacted with a dilute solution of EuAl, in the molar A1 to Ti ratio specified in
  • Co-catalyst A bis(hydrogenated tallow alkyl)methylammonium tetrakis(pentafluoro phenyl)borate(l-) amine
  • Polymer 1 (Poly. 1) is Resin 1 described above.
  • Polymer 2 (Poly. 2) is ASPUNTM 6835, a polyethylene composition and linear low density polyethylene fiber resin commercially available from The Dow Chemical Company (Midland, MI).
  • Polymer 3 (Poly. 3) is Resin 2 described above.
  • Polymer 4 (Poly. 4) is Resin 3 described above.
  • Polymer 5 (Poly. 5) is Resin 4 described above.
  • Polymer 6 (Poly. 6) is ELITETM 5860, a polyethylene composition and an enhanced polyethylene resin commercially available from The Dow Chemical Company (Midland, MI).
  • Poly. 1 to Poly. 6 have a density, melt index (12), molecular weight distribution (Mw/Mn), crystallization temperature (Tc), and melting temperature (Tm), as reported in Table 3 below. [0088] Table 3 - Properties of Poly. 1 to Poly. 6
  • Fibers are spun on a Hills Bicomponent Continuous Filament Fiber Spinning Line.
  • Bicomponent fibers having an eccentric core sheath configuration are made.
  • the fibers are spun on the Hills Line according to the following conditions. Extruder profiles are adjusted to achieve a melt temperature of 240°C. Throughput rate of each hole is 0.5 ghm (grams per hour per minute).
  • a Hills Bicomponent die is used and operated at a 40/60 core/sheath ratio (in weight) with the first region comprising an example in one extruder and second region comprising another example in the other extruder, in accordance with Table 4 below, to form Inventive Examples 1, 2, 3, and 4, and Comparative Examples 1, 2, 3, 4, 5 and 6.
  • the Hills Line pressure is set at 40 psi.
  • the die consists of 144 holes, with a hole diameter of 0.6 mm and a length/diameter (L/D) of 4/1. Quench air temperature and flow rate are set at 15-18 °C, and 520cfm (cubic fit per minute), respectively. After the quenching zone, a draw tension is applied on the 144 filaments by pneumatically entraining the filaments in a slot unit with an air stream. Velocity of the air stream is controlled by the slot aspirator pressure.
  • Table 5 provides the difference in melting temperature (DTih), difference in crystallization temperature (ATc), and difference in density (ADensity) between the first region minus the second region for Inventive Examples 1 and 2 and Comparative Examples 1 and 2, examples which have a polyethylene composition in the first region with a molecular weight distribution (Mw/Mn) of less than 3.
  • Table 6 provides the difference in melting temperature (ATm), difference in crystallization temperature (ATc), and difference in density (ADensity) between the first region minus the second region for Inventive Examples 3 and 4 and Comparative Examples 3, 4, and 5, examples which have a polyethylene composition in the first region with a molecular weight distribution (Mw/Mn) of greater than 3.
  • Table 8 shows the amount of curvature related to the Examples. Inventive Example 1 to 4 have significantly higher curvature than the Comparative Examples, which have no curvature.
  • Table 9 provides the centroid off-set and radius of fiber data for certain examples.

Abstract

L'invention concerne des fibres à deux composants présentant une courbure améliorée. La fibre à deux composants comprend une première région et une seconde région. La première région comprend une première composition de polyéthylène et la seconde région comprend une seconde composition de polyéthylène, la première composition de polyéthylène ayant une température de cristallisation (Tc) supérieure à une température de cristallisation (Tc) de la seconde composition de polyéthylène. La fibre à deux composants peut être utilisée pour former un non-tissé.
PCT/US2021/030904 2020-05-08 2021-05-05 Fibres à deux composants présentant une courbure améliorée WO2021226246A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US17/997,615 US20230272567A1 (en) 2020-05-08 2021-05-05 Bicomponent fibers with improved curvature
JP2022564105A JP2023524202A (ja) 2020-05-08 2021-05-05 改善された曲率を有する二成分繊維
KR1020227042285A KR20230009911A (ko) 2020-05-08 2021-05-05 곡률이 개선된 이성분 섬유
EP21728706.9A EP4146853A1 (fr) 2020-05-08 2021-05-05 Fibres à deux composants présentant une courbure améliorée
BR112022022436A BR112022022436A2 (pt) 2020-05-08 2021-05-05 Fibra bicomponente, e, não tecido de fiação contínua
CN202180033534.2A CN115516144A (zh) 2020-05-08 2021-05-05 具有改进的曲率的双组分纤维

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202063021784P 2020-05-08 2020-05-08
US63/021,784 2020-05-08

Publications (1)

Publication Number Publication Date
WO2021226246A1 true WO2021226246A1 (fr) 2021-11-11

Family

ID=76181230

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2021/030904 WO2021226246A1 (fr) 2020-05-08 2021-05-05 Fibres à deux composants présentant une courbure améliorée

Country Status (8)

Country Link
US (1) US20230272567A1 (fr)
EP (1) EP4146853A1 (fr)
JP (1) JP2023524202A (fr)
KR (1) KR20230009911A (fr)
CN (1) CN115516144A (fr)
AR (1) AR121943A1 (fr)
BR (1) BR112022022436A2 (fr)
WO (1) WO2021226246A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4209629A1 (fr) * 2022-01-05 2023-07-12 Borealis AG Utilisation de composition polymère pour la fabrication de tissus non tissés doux
WO2023131591A1 (fr) * 2022-01-05 2023-07-13 Fibertex Personal Care A/S Matériau non tissé comprenant des fibres multicomposants frisées

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0522995A2 (fr) * 1991-07-05 1993-01-13 Danaklon A/S Fibres de polyéthylène à deux composants
US6303220B1 (en) * 1998-11-30 2001-10-16 Chisso Corporation Polyethylene fiber and a non-woven fabric using the same
WO2009111185A2 (fr) * 2008-02-29 2009-09-11 Dow Global Technologies Inc. Fibres et tissus fabriqués à partir d’interpolymères éthylène/α-oléfine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0522995A2 (fr) * 1991-07-05 1993-01-13 Danaklon A/S Fibres de polyéthylène à deux composants
US6303220B1 (en) * 1998-11-30 2001-10-16 Chisso Corporation Polyethylene fiber and a non-woven fabric using the same
WO2009111185A2 (fr) * 2008-02-29 2009-09-11 Dow Global Technologies Inc. Fibres et tissus fabriqués à partir d’interpolymères éthylène/α-oléfine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WILLIAMSWARD, J. POLYM. SCI., POLYM. LETTERS, vol. 6, 1968, pages 621

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4209629A1 (fr) * 2022-01-05 2023-07-12 Borealis AG Utilisation de composition polymère pour la fabrication de tissus non tissés doux
WO2023131531A1 (fr) * 2022-01-05 2023-07-13 Borealis Ag Utilisation d'une composition polymère pour la fabrication de non tissés mous
WO2023131591A1 (fr) * 2022-01-05 2023-07-13 Fibertex Personal Care A/S Matériau non tissé comprenant des fibres multicomposants frisées

Also Published As

Publication number Publication date
EP4146853A1 (fr) 2023-03-15
AR121943A1 (es) 2022-07-27
BR112022022436A2 (pt) 2022-12-20
KR20230009911A (ko) 2023-01-17
US20230272567A1 (en) 2023-08-31
CN115516144A (zh) 2022-12-23
JP2023524202A (ja) 2023-06-09

Similar Documents

Publication Publication Date Title
EP2245221B1 (fr) Fibres et non tissés dotés de propriétés mécaniques améliorées
CN102105528B (zh) 可拉伸聚丙烯-基无纺布
KR101260112B1 (ko) 결합 특성이 향상된 섬유 및 부직포
US20230272567A1 (en) Bicomponent fibers with improved curvature
EP3884095B1 (fr) Tissu non tissé ayant des fibres de polymère d'éthylène/alpha-oléfine
US20220228297A1 (en) Method of manufacture of curly fibers
US20230248585A1 (en) Reusable outer cover formed from a nonwoven
US20220049377A1 (en) Crimped multi-component fibers
US20230257919A1 (en) Bicomponent fibers including ethylene/alpha-olefin interpolymers
WO2023039337A1 (fr) Fibres courbées à deux composants
US20240130901A1 (en) Feminine hygiene articles and film with improved softness and hand feel
EP4353208A1 (fr) Articles d'hygiène féminine et film présentant une souplesse et une sensation de main améliorées
EP3956512B1 (fr) Bandes non tissées et leurs procédés de fabrication

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21728706

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022564105

Country of ref document: JP

Kind code of ref document: A

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112022022436

Country of ref document: BR

ENP Entry into the national phase

Ref document number: 20227042285

Country of ref document: KR

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 2021728706

Country of ref document: EP

Effective date: 20221208

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 112022022436

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20221104