High loft nonwoven fabric

Abstract

Provided is a nonwoven fabric comprising a plurality of crimped bicomponent fibers, the crimped bicomponent fibers having a first component comprising a first polymeric material and a second component comprising a second polymeric material. The first polymeric material comprises a first polymer or a first polymer blend, wherein the second polymeric material comprises a second polymer blend of (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibilizing agent comprising or consisting of at least one polypropylene-polyethylene copolymer.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 256,796, filed October 18, 2021, pursuant to 35 USC §119(e), the entire disclosure of which is expressly incorporated herein by reference. Technical Field

[0003] Embodiments of the present invention generally relate to nonwoven fabrics having a plurality of crimped bicomponent fibers having a first component comprising a first polymer material and a second component comprising a second polymer material, the first polymer material comprising a first polymer or a first polymer blend, wherein the second polymer material comprises a second polymer blend of: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer and (iii) at least one compatibilizer comprising or consisting of at least one polypropylene-polyethylene copolymer. Background Technology

[0004] In nonwoven fabrics, the fibers forming the nonwoven fabric are typically oriented in the xy plane of the fiber web. This results in a relatively thin nonwoven fabric with a lack of bulk or significant thickness in the z-direction. The bulk or thickness of nonwoven fabrics suitable for hygiene-related products (e.g., personal care absorbent articles) improves user comfort (softness), flow handling, and facilitates fluid distribution to adjacent components of the article. In this regard, high-bulk, low-density nonwoven fabrics are used in a variety of end-use applications, such as for hygiene-related products (e.g., sanitary pads and napkins, disposable diapers, incontinence pads, etc.). For example, high-bulk, low-density nonwoven fabrics can be used in products such as towels, industrial wipes, incontinence products, baby care products (e.g., diapers), absorbent feminine care products, and professional healthcare products. Summary of the Invention

[0005] One or more embodiments of the present invention can solve one or more of the above-mentioned problems. Some embodiments of the present invention provide a nonwoven fabric comprising a plurality of crimped bicomponent fibers having a first component comprising a first polymer material and a second component comprising a second polymer material, the first polymer material comprising a first polymer or a first polymer blend, wherein the second polymer material comprises a second polymer blend comprising: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer and (iii) at least one compatibilizer comprising or consisting of at least one polypropylene-polyethylene copolymer.

[0006] In another aspect, the present invention provides a method for manufacturing a nonwoven fabric. The method may include the following steps: (a) forming a first polymer melt comprising a first polymer or a blend of a first polymer; (b) forming a second polymer melt comprising a second polymer blend of: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibilizer comprising a polypropylene-polyethylene copolymer; (c) melt-spinning the first and second polymer melts through a two-component spinneret assembly to form a plurality of bicomponent fibers; (d) crimping the plurality of bicomponent fibers before or during deposition on a collection surface, or subjecting the plurality of bicomponent fibers to a crimping operation to provide a plurality of crimped bicomponent fibers; and (e) consolidating the plurality of crimped bicomponent fibers to form a nonwoven fabric.

[0007] In another aspect, the present invention provides a method for manufacturing a nonwoven fabric. The method may include the following steps: (a) forming a first polymer melt comprising a first polymer or a blend of a first polymer; (b) forming a second polymer melt comprising a second polymer blend of: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibilizer comprising a polypropylene-polyethylene copolymer; (c) melt-spinning the first and second polymer melts through a two-component spinneret assembly to form a plurality of bicomponent fibers; (d) consolidating the plurality of bicomponent fibers to form an intermediate nonwoven fabric; and (e) subjecting the plurality of bicomponent fibers of the intermediate nonwoven fabric to a crimping operation to provide a nonwoven fabric.

[0008] In another aspect, the present invention provides an article comprising one or more nonwoven fabrics as described and disclosed herein. This article may include adult diapers, baby diapers, pull-ups, and feminine hygiene pads.

[0009] According to certain embodiments of the invention, the article may include a top sheet comprising a nonwoven fabric as described and disclosed herein. Attached Figure Description

[0010] Various embodiments of the invention will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, of the embodiments of the invention. In fact, these inventions can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable this disclosure to meet applicable legal requirements. The same numerals always denote the same elements, and wherein:

[0011] Figure 1 Crimped bicomponent fibers according to certain embodiments of the present invention are shown; and

[0012] Figure 2A-2H Examples of exemplary bicomponent fibers are shown in cross-sectional views according to certain embodiments of the present invention. Detailed Implementation

[0013] Various embodiments of the invention will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, of the embodiments of the invention. In fact, these inventions can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable this disclosure to meet applicable legal requirements. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise.

[0014] The terms “basically” or “substantially” may cover the total amount specified in certain embodiments of the invention, or, in other embodiments of the invention, largely but not the specified total amount (e.g., 95%, 96%, 97%, 98%, or 99% of the specified total amount).

[0015] The term "polymer" or "polymerized," as used interchangeably herein, may include homopolymers, copolymers such as block, graft, random and alternating copolymers, terpolymers, etc., and their blends and modifications. Furthermore, unless specifically limited otherwise, the term "polymer" or "polymerized" shall include all possible structural isomers; stereoisomers, including but not limited to geometric isomers, optical isomers, or enantiomers; and / or any chiral molecular configuration of such polymer or polymeric material. These configurations include, but are not limited to, isotactic, syndiotactic, and atactic configurations of such polymer or polymeric material. The term "polymer" or "polymerized" shall also include polymers made from various catalyst systems, including but not limited to Ziegler-Natta catalyst systems and metallocene / single-center catalyst systems. According to certain embodiments of the invention, the term "polymer" or "polymerized" shall also include polymers produced by fermentation methods or of biological origin.

[0016] As used herein, the terms "nonwoven" and "nonwoven fiber web" can include fiber webs having a structure of single fibers, filaments, and / or threads interwoven in an interlaced manner but not in a repeating manner as identifiable in knitted or woven fabrics. According to certain embodiments of the invention, nonwoven fabrics or fiber webs can be formed by any method conventionally known in the art, such as meltblown, spunbond, needle punching, hydraulic entanglement, air-laid web formation, and bonded carding. As used herein, a "nonwoven fiber web" can include multiple individual fibers that have not undergone a consolidation process.

[0017] As used herein, the terms “fabric” and “nonwoven fabric” can include fiber webs in which multiple fibers are mechanically entangled or interconnected, fused together and / or chemically bonded together. For example, a bonding or consolidation process can be applied to a nonwoven fiber web of individually laid fibers to bond at least a portion of the individual fibers together to form a bonded (e.g., cohesive) fiber web of interconnected fibers.

[0018] As used herein, the terms "consolidated" and "consolidated" can include bringing together at least a portion of the fibers of a nonwoven fiber web to bring them closer together or attach them therebetween (e.g., thermally fused together, chemically bonded together, and / or mechanically entangled together) to form one or more bonded sites that, compared to an unconsolidated fiber web, increase resistance to external forces (e.g., abrasion and tension). For example, one or more bonded sites can include discrete or localized regions of the fiber web material that have been softened or melted and optionally subsequently or simultaneously compressed to create discrete or localized deformations within the fiber web material. Furthermore, the term "consolidated" can include the entire nonwoven fiber web that has been processed such that at least a portion of the fibers are brought closer together or attached therebetween (e.g., thermally fused together, chemically bonded together, and / or mechanically entangled together), such as by thermal bonding or mechanical entanglement (e.g., hydraulic entanglement), as are just a few examples. According to certain embodiments of the invention, such a fiber web can be considered a "consolidated nonwoven material," a "nonwoven fabric," or simply a "fabric."

[0019] As used herein, the term "short fiber" can include fibers cut from filaments. According to some embodiments, any type of filament material can be used to form short fibers. For example, short fibers can be formed from polymer fibers and / or elastomer fibers. Non-limiting examples of materials may include polyolefins (e.g., polypropylene or polypropylene-containing copolymers), polyethylene terephthalate, and polyamides. By way of example only, the average length of short fibers can range from about 2 cm to about 15 cm.

[0020] As used herein, the term "spunbond" can include fibers formed by extruding molten thermoplastic material as a filament from a plurality of fine, typically circular capillaries of a spinneret, followed by a rapid reduction in the diameter of the extruded filament. According to embodiments of the invention, spunbond fibers are generally non-sticky upon deposition onto a collection surface and can be substantially continuous as disclosed and described herein. It should be noted that spunbond materials used in certain composites of the invention can include those described in the literature. Nonwoven materials. Spunbond fibers may include, for example, continuous fibers.

[0021] As used herein, the term "continuous fiber" refers to a fiber that is not cut from its original length before being formed into a nonwoven fiber web or nonwoven fabric. The average length of a continuous fiber can be greater than about 15 centimeters to greater than one meter, and can be up to the length of the resulting fiber web or fabric. For example, the continuous fiber used herein may include fibers in which the fiber length is at least 1,000 times greater than the average fiber diameter, such as at least about 5,000, 10,000, 50,000, or 100,000 times greater than the average fiber diameter.

[0022] According to certain embodiments of the invention, the term "meltblown" as used herein may include fibers formed by extruding molten thermoplastic material as melt wires or filaments through multiple fine-die capillary tubes into a converging high-speed (typically hot) gas (e.g., air) stream, which thins the molten thermoplastic material filaments to reduce their diameter, which may be the diameter of microfibers. According to embodiments of the invention, the die capillary tubes may be circular. The meltblown fibers are then carried by the high-speed gas flow and deposited on a collection surface to form a fiber web of randomly distributed meltblown fibers. The meltblown fibers may include microfibers, which may be continuous or discontinuous, and are typically tacky when deposited on the collection surface. However, the length of meltblown fibers is shorter than that of spunbond fibers.

[0023] As used herein, the term “layer” may include a generally identifiable combination of similar material types and / or functions present in the XY plane.

[0024] As used herein, the term "multicomponent fiber" can include fibers formed from at least two different polymeric materials (e.g., two or more), said polymeric materials being extruded from separate extruders but spun together to form a single fiber. The term "bicomponent fiber" as used herein can include fibers formed from two different polymeric materials, said polymeric materials being extruded from separate extruders but spun together to form a single fiber. The polymeric materials or polymers are arranged in substantially constant positions in different regions of the cross-section of the multicomponent fiber and extend continuously along the length of the multicomponent fiber. The configuration of such a multicomponent fiber can be, for example, a core-sheath configuration, in which one polymer is surrounded by another polymer; an eccentric core-sheath configuration, including a sheath component and a core component, wherein the core component defines at least a portion of the outer surface of the bicomponent fiber having an eccentric core-sheath configuration; or it can be a side-by-side arrangement, a disc arrangement, or an "island" arrangement, each as multicomponent, including those known in the field of bicomponent fibers.

[0025] As used herein, the term "monocomponent fiber" can include fibers formed from a single polymer or a polymer blend (e.g., a blend or mixture of two or more polymers) extruded from a single extruder. For example, a single polymer or polymer blend may define a polymer matrix in which one or more additives (e.g., fillers) can be dispersed.

[0026] As used herein, the term "high bulk" includes materials that can typically have a z-direction thickness exceeding about 0.3 mm and a relatively low bulk density. The thickness of "high bulk" nonwovens and / or layers can be greater than 0.3 mm (e.g., greater than 0.4 mm, greater than 0.5 mm, greater than 0.6 mm, greater than 0.8 mm, or greater than 1 mm), such as using ProGage Thickness, available from Thwig-Albert Instrument Co. (West Berlin, NJ 08091). The tester (model 89-2009) measures the material using a 2″ diameter foot with a force of 1.45 kPa applied during the measurement. According to certain embodiments of the invention, the thickness of the "high-bulk" nonwoven fabric and / or layer can be at most about any one of the following: 3, 2.75, 2.5, 2.25, 2, 1.75, 1.5, 1.25, 1.0, 0.75, and 0.5 mm and / or at least about any one of the following: 0.3, 0.4, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, and 2.0 mm. As used herein, the "high-bulk" nonwoven fabric and / or layer can additionally have a relatively low density (e.g., bulk density—weight / unit volume), for example, less than about 60 kg / m³. 3 For example, at most approximately any of the following: 70, 60, 55, 50, 45, 40, 35, 30, and 25 kg / m 3 And / or at least about any one of the following: 10, 15, 20, 25, 30, 35, 40, 45, 50 and 55 kg / m 3 .

[0027] As used herein, the term "longitudinal" or "MD" refers to the direction in which the fabric is produced or conveyed. The term "transverse" or "CD" as used herein refers to the direction in which the fabric is substantially perpendicular to the MD.

[0028] As used herein, the term "aspect ratio" refers to the ratio of the length of the major axis to the length of the minor axis of the fiber cross section.

[0029] All integer endpoints that can generate smaller ranges within the given ranges disclosed herein are within the scope of certain embodiments of the invention. For example, the disclosed ranges of about 10 to about 15 include intermediate ranges, such as about 10 to about 11; about 10 to about 12; about 13 to about 15; about 14 to about 15; and so on. Furthermore, all individual decimal endpoints (e.g., reporting to the nearest tenth of a digit) that can generate smaller ranges within the given ranges disclosed herein are within the scope of certain embodiments of the invention. For example, the disclosed ranges of about 1.5 to about 2.0 include intermediate ranges, such as about 1.5 to about 1.6; about 1.5 to about 1.7; about 1.7 to about 1.8; and so on.

[0030] In one aspect, the present invention provides a nonwoven fabric comprising a plurality of crimped bicomponent fibers having a first component comprising a first polymer material and a second component comprising a second polymer material, the first polymer material comprising a first polymer or a blend of first polymers, wherein the second polymer material comprises a blend of second polymers containing: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibilizer comprising or consisting of at least one polypropylene-polyethylene copolymer. According to certain embodiments of the invention, the nonwoven fabric comprises a high-loft nonwoven fabric wherein the plurality of crimped bicomponent fibers impart a desired loft (e.g., thickness in the z-direction perpendicular to the transverse and longitudinal directions of the nonwoven fabric).

[0031] For example, Figure 1 A crimped bicomponent fiber 50 according to certain embodiments of the present invention is shown, wherein the crimped bicomponent fiber 50 comprises a plurality of three-dimensional crimped or helical crimped portions. Although Figure 1 The crimped bicomponent fiber 50 shows multiple three-dimensional coiled or helical coiled portions, but the crimped bicomponent fiber may additionally or alternatively include at least one discrete zigzag coiled portion, at least one discrete helical coiled portion, or a combination thereof.

[0032] According to certain embodiments of the invention, the plurality of crimped bicomponent fibers may comprise an average free crimp percentage of about 30% to about 300%, for example, up to about any one of the following: 300, 275, 250, 225, 200, 175, 150, 125, 100, and 75% and / or at least about any one of the following: 20, 30, 40, 50, 75, 100, 125, 150, 175, and 200%. Additionally or alternatively, the plurality of crimped bicomponent fibers comprise an average free crimp length of about 10 mm to about 50 mm, for example, at least about any one of the following: 10, 12, 14, 15, 16, 18, 20, 22, 24, and 25 mm, and / or up to about any one of the following: 50, 45, 40, 38, 35, 32, 30, 28, and 25 mm. The average free crimp percentage can be determined by measuring the free crimp length of the fiber in question using an Instron 5565 equipped with a 2.5N load sensor. In this process, a free or unstretched fiber bundle can be placed in the machine's clamps. The free crimp length can be measured at the point where the load on the fiber bundle (e.g., the 2.5N load sensor) becomes constant. The free crimp length is determined using the following parameters: (i) recording the approximate weight of the free fiber bundle in grams (e.g., xxx g ± 0.002 g); (ii) recording the unstretched bundle length in inches; (iii) setting the Instron gauge length (i.e., the distance or gap between the clamps holding the fiber bundle) to 1 inch; and (iv) setting the crosshead speed to 2.4 inches / minute. The free crimp length of the fiber can then be determined by recording the fiber extension length at the point where the load becomes constant (i.e., the fiber is fully extended). The average free crimp percentage can be calculated from the free crimp length of the fiber in question and the unstretched fiber bundle length (e.g., gauge length). For example, when using a 1-inch (25.4 mm) gauge length as described above, a measured free crimp length of 32 mm will provide approximately 126% of the average free crimp percentage. This method of determining the average free crimp percentage may be particularly advantageous when evaluating continuous fibers with helical crimp. For instance, conventional textile fibers are mechanically crimped and can be measured optically, but continuous fibers with helical crimp portions introduce errors when attempting to optically count the "creases" in such fibers.

[0033] According to certain embodiments of the invention, a plurality of crimped bicomponent fibers may include a plurality of three-dimensional crimped portions with an average diameter (e.g., based on an average of the longest lengths defining individual crimped portions) of about 0.5 mm to about 5 mm, for example, up to about any one of the following: 5, 4.75, 4.5, 4.25, 4, 3.75, 3.5, 3.25, 3, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2, 1.9, 1.8, 1.7, 1.6 and 1.5 mm and / or at least about any one of the following: 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 and 2 mm. According to certain embodiments of the present invention, the average diameter of multiple three-dimensional crimped portions can be determined by observing a multi-component fiber sample using a digital optical microscope (manufactured by HiRox, Japan, KH-7700) and obtaining a digital measurement of the loop diameter of the three-dimensional crimped portions of the SMF. Typically, a magnification range of 20x to 40x can be used to easily evaluate the loop diameter formed by the three-dimensional crimping of multi-component fibers.

[0034] According to certain embodiments of the invention, a plurality of crimped bicomponent fibers may comprise a plurality of three-dimensional crimped portions with an average diameter (e.g., based on an average of the longest lengths defining individual crimped portions) of about 10 mm to about 40 mm, for example, up to about any of the following: 40, 38, 35, 32, 30, 28, and 25 mm and / or at least about any of the following: 10, 12, 15, 18, 20, 22, and 25 mm. According to certain embodiments of the invention, the average diameter of the plurality of three-dimensional crimped portions can be determined by observing the multicomponent fiber sample using a digital optical microscope (manufactured by HiRox, Japan, KH-7700) and obtaining a digital measurement of the loop diameter of the three-dimensional crimped portions of the SMF. Typically, a magnification range of 20x to 40x can be used to readily evaluate the loop diameter formed by the three-dimensional crimping of the multicomponent fibers.

[0035] According to certain embodiments of the present invention, the first polymer material may include a polyolefin, such as one or more polypropylenes, one or more polyethylenes, or any combination thereof. For example, the first polymer material may include the total polymer content attributable to a single polymer or a first polymer blend, the first polymer blend including, for example, a first polypropylene having a first melt flow rate (MFR) and a second polypropylene having a second MFR, wherein the second MFR is equal to or greater than the first MFR. According to certain embodiments of the invention, the first MFR ratio between the second MFR and the first MFR is at least about 1:1, for example at least about any of the following: 1:1, 1.2:1, 1.4:1, 1.5:1, 1.6:1, 1.8:1, 2:1, 4:1, 5:1, 6:1, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, 22:1, 24:1 and 25:1, and / or at most about any of the following: 60:1, 55:1, 50:1, 48:1, 46:1, 45:1, 44:1, 42:1, 40:1, 38:1, 36:1, 35:1, 34:1, 32:1, 30:1, 28:1, 26:1 and 25:1.

[0036] According to certain embodiments of the invention, the first polymer material may comprise about 70 wt% to about 99 wt% of a first polypropylene, for example at least about any one of the following: 70 wt%, 75 wt%, 80 wt%, 85 wt%, and 90 wt%, and / or at most about any one of the following: 99, 98, 97, 96, 95, 94, 93, 92, 91, and 90 wt%. Additionally or alternatively, the first polymer material may comprise about 1 wt% to about 10 wt% of a second polypropylene, for example at least about any one of the following: 1, 2, 3, 4, and 5 wt%, and / or at most about any one of the following: 10, 9, 8, 7, 6, and 5 wt%.

[0037] According to certain embodiments of the invention, the MFR (i.e., the first MFR) of the first polypropylene of the first polymer material is about 10 g / 10 min to about 100 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), for example at least about any one of the following: 10, 15, 20, 22, 25, 28, 30, 32, 35, 38 and 40 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), and / or at most about any one of the following: 100, 90, 80, 70, 60, 50 and 40 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg). Alternatively or concurrently, the MFR (i.e., the second MFR) of the second polypropylene of the first polymer material may be from about 500 g / 10 min to about 2500 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), for example at least about any one of the following: 500, 550, 600, 700, 800, 900, 1000, 1200, 1500 and 1800 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), and / or at most about any one of the following: 2500, 2400, 2300, 2200, 2100, 2000, 1900 and 1800 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg).

[0038] According to certain embodiments of the invention, the second polymer blend may comprise about 60 wt% to about 90 wt% of at least one polypropylene polymer (e.g., a single polypropylene polymer or a combination of polypropylene polymers), for example at least about any one of the following: 60, 62, 64, 65, 66, 68, 70, 72, 74, 77, 78, and 80 wt% of at least one polypropylene polymer, and / or at most about any one of the following: 90, 88, 86, 85, 84, 83, 82, 81, and 80 wt% of at least one polypropylene polymer. For example, the at least one polypropylene polymer may be a first polypropylene polymer, which may be the same as or different from the first polypropylene used in the first polymer blend, and / or a second polypropylene polymer, which may be the same as or different from the second polypropylene used in the first polymer blend. According to certain embodiments of the invention, at least one polypropylene polymer (e.g., a single polypropylene polymer or a combination of polypropylene polymers) of the second polymer blend may have a melt flow rate (MFR) of about 10 to about 150 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), for example at least about any of the following: 10, 12, 14, 16, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48 and 50 g / 10 min, and / or at most about any of the following: 150, 140, 130, 120, 110, 100, 95, 90, 85, 80, 75, 70, 65, 60, 58, 56, 55, 54, 52 and 50 g / 10 min. For example, the second polymer blend may include a variety of different polypropylene polymers, and the weight-average MFR of the combination of the various different polypropylene polymers may be within any of the above ranges.

[0039] According to certain embodiments of the invention, the second polymer blend may comprise about 5 to about 30 wt% of at least one polyethylene polymer, for example, at least about any one of the following: 5, 6, 8, 10, 12, 14, and 15 wt% of at least one polyethylene polymer, and / or at most about any one of the following: 30, 28, 26, 25, 24, 22, 20, 18, 16, and 15 wt% of at least one polyethylene polymer. For example, the at least one polyethylene polymer may be the first polyethylene polymer. According to certain embodiments of the invention, the at least one polyethylene polymer may have a melt flow rate (MFR) of about 1 to about 40 g / 10 min, as determined by ASTM D1238 (190°C / 2.16 kg), for example, at least about any one of the following: 1, 2, 4, 5, 6, 8, 10, 12, 14, and 15 g / 10 min, and / or at most about any one of the following: 40, 35, 30, 25, 20, 18, 16, and 15 g / 10 min.

[0040] According to certain embodiments of the invention, the second polymer blend may comprise about 1 wt% to about 10 wt% of at least one polypropylene-polyethylene copolymer (e.g., a compatibilizer), for example at least about any one of the following: 1, 2, 3, 4, and 5 wt% of at least one polypropylene-polyethylene copolymer, and / or at most about any one of the following: 10, 9, 8, 7, 6, and 5 wt% of at least one polypropylene-polyethylene copolymer. The at least one polypropylene-polyethylene copolymer may, for example, be a first polypropylene-polyethylene copolymer (e.g., a monopolypropylene-polyethylene copolymer). The first polypropylene-polyethylene copolymer may comprise a first block copolymer or a first random copolymer. According to certain embodiments of the invention, the first polypropylene-polyethylene copolymer is an EP-iPP diblock polymer.

[0041] According to certain embodiments of the invention, the first polypropylene-polyethylene copolymer may have an ethylene monomer content of about 5 to about 60 wt%, for example at least about any one of the following: 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 26, 38, 40, 42, 44 and 45 wt%, and / or at most about any one of the following: 60, 58, 56, 55, 54, 52, 50, 48, 46 and 45 wt%. Alternatively or concurrently, at least one polypropylene-polyethylene copolymer (e.g., a first polypropylene-polyethylene copolymer) may have a melt flow rate (MFR) of about 0.5 g / 10 min to about 20 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), for example at least about any one of the following: 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 and 10 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), and / or at most about any one of the following: 20, 19, 18, 17, 16, 15, 14, 13, 12, 11 and 10 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg). According to certain embodiments of the invention, in the second polymer material, the second MFR ratio between the third MFR (as determined by ASTM D1238 (230°C / 2.16kg) of at least one polypropylene polymer and the fourth MFR (as determined by ASTM D1238 (230°C / 2.16kg)) of at least one polyethylene polymer can be from about 5:1 to about 20:1, for example, at least about any of the following: 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1 and 12:1, and / or at most about any of the following: 20:1, 19:1, 18:1, 17:1, 16:1, 15:1, 14:1, 13:1 and 12:1.Alternatively, the MFR of the second polymer blend may be about 20 to about 120 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), for example at least about any one of the following: 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38 and 40 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg), and / or at most about any one of the following: 120, 110, 100, 90, 80, 70, 60, 59, 58, 56, 55, 54, 52, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41 and 40 g / 10 min, as determined by ASTM D1238 (230°C / 2.16 kg).

[0042] Recent advances in single-center catalysts (e.g., metallocene catalysts) have enabled the production of a variety of polymer structures that were previously difficult or impossible to produce economically. In this regard, first polypropylene-polyethylene copolymers can comprise copolymers formed by single-center catalysts, such as metallocene-catalyzed copolymers. For example, polypropylene-based polymers with significant amounts of ethylene content can be produced in a variety of configurations (e.g., well-defined blocks) to further enhance the copolymer's ability to bridge typically immiscible polymers. Examples of such materials include Vistamaxx. TM (e.g., Vistamaxx) TM 6202), which is a polypropylene-based elastomer comprising a copolymer of propylene and ethylene. These propylene-based elastomers, for example, comprise isotactic polypropylene microcrystalline regions and random amorphous regions (e.g., ethylene). Such olefin copolymers may include hard blocks and soft blocks, wherein the hard blocks are primarily propylene and the soft blocks are primarily ethylene. In this respect, the hard blocks (e.g., propylene) may constitute 10-90 wt% of the copolymer, while the soft blocks may constitute 90-10 wt% of the copolymer. In this respect, these copolymers include randomly distributed ethylene throughout the copolymer. TM (e.g., Vistamaxxx) TM The 6202 copolymer is commercially available from ExxonMobil. Vistamaxx TM 6202 has a density of 0.862 g / cc, an MI (190℃ / 2.16 kg) of 9.1, an MFR (230℃ / 2.16 kg load) of 20, and an ethylene content of 15% by weight. Other examples include olefin diblock copolymers, including EP-iPP diblock polymers such as Intune. TMThis is a polypropylene-based block copolymer comprising ethylene monomers. According to certain embodiments of the invention, the first polypropylene-polyethylene copolymer disclosed herein can be prepared, for example, by contacting an addition-polymerizable monomer or a mixture of monomers under addition polymerization conditions with a composition comprising at least one addition catalyst, a co-catalyst, and a chain shuttle (“CSA”), wherein the method is characterized by forming at least some grown polymer chains under different process conditions in two or more reactors operating under steady-state polymerization conditions or in two or more zones of a reactor operating under plug flow polymerization conditions. According to certain embodiments of the invention, the first polypropylene-polyethylene copolymer may comprise an olefin block copolymer formed by a single-center catalyst or other catalyst system. That is, according to certain embodiments of the invention, the first polypropylene-polyethylene copolymer may not be prepared by a single-center catalyst. According to certain embodiments of the invention, the first polypropylene-polyethylene copolymer does not contain anhydride functional groups, such as maleic anhydride functional groups.

[0043] According to certain embodiments of the invention, copolymers formed from the single-center catalyst described above can be distinguished from conventional random copolymers, physical blends of polymers, and block copolymers prepared by sequential monomer addition. These copolymers differ from random copolymers in characteristics such as higher melting temperatures for a considerable number of comonomers and a block complexation index, as described below; from physical blends in characteristics such as a block complexation index, better tensile strength, improved breaking strength, finer morphology, improved optical properties, and greater impact strength at lower temperatures; and from block copolymers prepared by continuous monomer addition in molecular weight distribution, rheology, shear thinning, rheological ratio, and the presence of block polydispersity.

[0044] As a further example, the first polypropylene-polyethylene copolymer may include an EP-iPP diblock polymer having an ethylene content of 43 to 48 wt%, or 43.5 to 47 wt%, or 44 to 47 wt%, based on the weight of the diblock copolymer. In an exemplary embodiment, the propylene content of the EP-iPP diblock polymer may be 57 to 52 wt%, or 56.5 to 53 wt%, or 56 to 53 wt%, based on the weight of the EP-iPP diblock polymer.

[0045] According to certain embodiments of the invention, the plurality of crimped bicomponent fibers have an average diameter (e.g., fiber diameter) of about 10 to about 30 micrometers, for example at least about any one of the following: 10, 12, 14, 15, 16, 18, and 20 micrometers, and / or at most about any one of the following: 30, 28, 26, 25, 24, 22, and 20 micrometers. Alternatively or additionally, the plurality of crimped bicomponent fibers may comprise continuous fibers, such as spunbond fibers, staple fibers, or combinations thereof.

[0046] According to certain embodiments of the invention, a plurality of crimped bicomponent fibers may include side-by-side configurations (e.g., circular or non-circular cross-sections), core-sheath configurations, disc configurations, island configurations, multi-leaf configurations, or any combination thereof. For example, a core-sheath configuration may include an eccentric core-sheath configuration comprising a sheath component and a core component, wherein the core component defines at least a portion of the outer surface of the plurality of bicomponent fibers having an eccentric core-sheath configuration.

[0047] Figure 2A-2H Examples of cross-sectional views of some non-limiting examples of multiple crimped bicomponent fibers according to certain embodiments of the present invention are shown. Figure 2A-2H As shown, a plurality of crimped bicomponent fibers 50 may include, for example, a first polymer component 52 of a first polymer composition A disclosed and described herein, and a second polymer component 54 of, for example, a second polymer composition B disclosed and described herein. The first and second components 52 and 54 may be arranged in substantially different regions within the cross-section of the plurality of bicomponent fibers, said regions extending substantially continuously along the length of the bicomponent fibers. The first and second components 52 and 54 can be arranged in a side-by-side manner, as shown in... Figure 2A The fibers shown in the circular cross-section, or arranged as shown in the diagram... Figure 2G and 2H In the strip-shaped (e.g., non-circular) cross-sectional fibers shown. Additionally or alternatively, the first and second components 52 and 54 can be arranged in a sheath / core configuration, for example... Figure 2B and 2C The eccentric skin / core arrangement is shown. Figure 2B In the eccentric skin / core type bicomponent fiber shown, one component completely encloses or surrounds another component, but is asymmetrically located within the multicomponent fiber to cause the fiber to curl (e.g., first component 52 surrounds component 54). Figure 2C The illustrated eccentric skin / core configuration includes a first component 52 (e.g., a skin component) that substantially surrounds a second component 54 (e.g., a core component), but the surround is incomplete, as a portion of the second component may be exposed and form part of the outermost surface of the fiber 50. As another example, bicomponent fibers may include, for instance... Figure 2D and 2E Hollow fibers as shown or such Figure 2F The multi-bladed fiber is shown. However, it should be noted that many other cross-sectional configurations and / or fiber shapes may be suitable according to certain embodiments of the invention.

[0048] In several bicomponent fibers, according to certain embodiments of the invention, the polymer components can be present in a ratio of about 85:15 to about 15:85 (by volume or mass). According to certain embodiments of the invention, a ratio of about 50:50 (by volume or mass) may be ideal; however, the specific ratio used can vary as needed, for example, up to about any of the following: 85:15, 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, and 50:50 by volume or mass, and / or at least about any of the following: 50:50, 45:55, 40:60, 35:65, 30:70, 25:75, 20:80, and 15:85 by volume or mass. Alternatively or concurrently, the first polymeric material may comprise about 20 wt% to about 80 wt% of a plurality of crimped bicomponent fibers, for example, at least about any one of the following: 20, 25, 30, 35, 40, 45, 50, and 55 wt%, and / or at most about any one of the following: 80, 75, 70, 65, 60, and 55 wt%. Alternatively or concurrently, the second polymeric material may comprise about 20 wt% to about 80 wt% of a plurality of crimped bicomponent fibers, for example, at least about any one of the following: 20, 25, 30, 35, 40, 45, 50, and 55 wt%, and / or at most about any one of the following: 80, 75, 70, 65, 60, and 55 wt%.

[0049] According to certain embodiments of the invention, the first polymer blend, the second polymer blend, or both may contain less than about 10 wt% of a total polypropylene-polyethylene copolymer, for example at least about any one of the following: 0, 0.5, 1, 2, 3, 4, and 5 wt%, and / or at most about any one of the following: 10, 9, 8, 7, 6, and 5 wt%. In this respect, the bicomponent fiber may contain a total polymer component having less than about 10 wt% of a total polypropylene-polyethylene copolymer, for example at least about any one of the following: 0, 0.5, 1, 2, 3, 4, and 5 wt%, and / or at most about any one of the following: 10, 9, 8, 7, 6, and 5 wt%.

[0050] According to certain embodiments of the present invention, the second polymer material may optionally further include a compatibilizer containing anhydride functional groups, such as maleic anhydride or a maleic anhydride-modified polymer. Alternatively or additionally, the first polymer material, the second polymer material, or both may also contain one or more fillers, such as one or more organic fillers and / or one or more inorganic fillers (e.g., particles of calcium carbonate, pigments, etc.). According to certain embodiments of the present invention, the first polymer material, the second polymer material, or both may further contain one or more slip agents, such as amides. These slip agents may, for example, contain primary amides, secondary amides, tertiary amides, diamides, or any combination thereof. According to certain embodiments of the present invention, the slip agent may contain one or more primary amides. For example, according to certain embodiments of the present invention, suitable primary amides as slip agents may include erucamide, oleamide, stearamide, behenamide, or any combination thereof. Alternatively or additionally, certain embodiments of the present invention may contain one or more slip agents containing one or more secondary amides. For example, according to certain embodiments of the present invention, suitable secondary amides as slip agents include oleyl palmitamide, stearyl erucamide, or any combination thereof. Alternatively or additionally, certain embodiments of the invention may include one or more slip agents comprising one or more bisamides, such as ethylenebisamide. For example, according to certain embodiments of the invention, suitable bisamides as slip agents include ethylene bis-stearamide, ethylene bis-oleamide, or any combination thereof. According to certain embodiments of the invention, the slip agent may comprise an amide (e.g., primary amide, secondary amide, tertiary amide, bisamide, etc.) comprising one or more saturated or unsaturated aliphatic chains. According to certain embodiments of the invention, each of the one or more aliphatic chains may independently comprise about 1 to about 30 carbon atoms (e.g., about 5 to about 30 carbon atoms). For example, secondary amides and bisamides may comprise two saturated and / or unsaturated carbon chains, each of which may independently comprise about 1 to about 30 carbon atoms (e.g., about 5 to about 30 carbon atoms). By way of example only, one or more aliphatic chains may each independently contain at least about any of the following: 1, 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 carbon atoms and / or at most about 30, 29, 28, 27, 26, 25, 20, and 15 carbon atoms (e.g., about 15 to about 25 carbon atoms, about 20 to 30 carbon atoms, etc.). According to certain embodiments of the invention, the slip agent may comprise an amide comprising an unsaturated aliphatic chain having one or more unsaturated elements or degrees of unsaturation. An unsaturated unit corresponds to two fewer hydrogen atoms than a saturated unit. For example, a single double bond occupies one unsaturated unit, while a triple bond occupies two unsaturated units. According to certain embodiments of the invention, the slip agent comprises an unsaturated aliphatic chain containing about 1 to about 10 unsaturated elements (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 saturated elements).

[0051] As described above, the plurality of crimped bicomponent fibers may include a circular cross-section, a non-circular cross-section, or both. For example, a non-circular cross-section may include a pie-shaped cross-section, a multi-leaf-shaped cross-section, or a strip-shaped cross-section. According to certain embodiments of the invention, the plurality of crimped bicomponent fibers include a non-circular cross-section with an aspect ratio of at least about 1.5:1, for example, about 1.5:1 to about 10:1.

[0052] According to certain embodiments of the invention, the plurality of crimped bicomponent fibers may comprise about 0 to about 100 wt% of fibers with a circular cross-section, for example, at least about any one of the following: 0, 5, 10, 20, 30, 40, and 50 wt%, and / or at most about any one of the following: 100, 95, 90, 80, 70, 60, and 50 wt%. Alternatively or additionally, the plurality of crimped bicomponent fibers may comprise about 0 to about 100 wt% of fibers with a non-circular cross-section, for example, at least about any one of the following: 0, 5, 10, 20, 30, 40, and 50 wt%, and / or at most about any one of the following: 100, 95, 90, 80, 70, 60, and 50 wt%.

[0053] According to certain embodiments of the invention, a plurality of crimped bicomponent fibers define a first nonwoven layer, and the nonwoven fabric further includes one or more additional nonwoven layers, such as at least a second nonwoven layer. In this respect, the nonwoven fabric may comprise a multilayer nonwoven fabric. The one or more additional layers may, for example, comprise a spunbond layer, a meltblown layer, a carded layer, a hydroentangled layer, a cellulose layer, or a combination thereof. According to certain embodiments of the invention, the nonwoven fabric includes one or more cellulose layers located directly or indirectly between the first and second nonwoven layers, wherein the second nonwoven layer comprises a second spunbond layer or a spunbond-meltblown-spunbond layer.

[0054] According to certain embodiments of the invention, the nonwoven fabric may have a basis weight of at least about 14 g / m² (gsm), for example at least about any of the following: 14, 16, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, 42, 45, 48, 50, 52, 55, 58 and 60 gsm, and / or at most about any of the following: 100, 95, 90, 85, 80, 75, 70, 65 and 60 gsm.

[0055] In another aspect, the present invention provides a method for manufacturing a nonwoven fabric. The method may include the following steps: (a) forming a first polymer melt comprising a first polymer or a blend of a first polymer; (b) forming a second polymer melt comprising a second polymer blend of: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibilizer comprising a polypropylene-polyethylene copolymer; (c) melt-spinning the first and second polymer melts through a two-component spinneret assembly to form a plurality of bicomponent fibers; (d) crimping the plurality of bicomponent fibers before or during deposition on a collection surface, or subjecting the plurality of bicomponent fibers to a crimping operation to provide a plurality of crimped bicomponent fibers; and (e) consolidating the plurality of crimped bicomponent fibers to form a nonwoven fabric. Alternatively, the method may include the following steps: (a) forming a first polymer melt comprising a first polymer or a blend of a first polymer; (b) forming a second polymer melt comprising a second polymer blend of: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibilizer comprising a polypropylene-polyethylene copolymer; (c) melt-spinning the first and second polymer melts through a bicomponent spinneret assembly to form a plurality of bicomponent fibers; (d) consolidating the plurality of bicomponent fibers to form an intermediate nonwoven fabric; and (e) subjecting the plurality of bicomponent fibers of the intermediate nonwoven fabric to a crimping operation to provide a nonwoven fabric. According to certain embodiments of the invention, the bicomponent spinneret assembly includes an orifice through which a plurality of bicomponent fibers are extruded.

[0056] According to certain embodiments of the invention, the step of forming the second polymer melt includes selecting and blending at an elevated temperature at at least one polypropylene polymer, at least one polyethylene polymer, and at least one polypropylene-polyethylene copolymer, wherein the MFR of the at least one polyethylene polymer is less than the MFR of the at least one polypropylene polymer at the elevated temperature, and the difference between the MFR of the at least one polypropylene polymer and the MFR of the at least one polyethylene polymer is less than about 35. For example, the difference between the MFR of the at least one polypropylene polymer and the MFR of the at least one polyethylene polymer can be from about 1 to about 35, for example, at least about any one of the following: 1, 3, 5, 8, 10, 12, 15, 18, and 20, and / or at most about any one of the following: 35, 32, 20, 28, 26, 25, 24, 22, and 20. In some embodiments of the invention, the elevated temperature can be from about 190°C to about 250°C, for example, at least about any one of the following: 190, 200, 210, and 215°C, and / or at most about any one of the following: 250, 245, 240, 235, 230, 225, 220, and 215°C. In some embodiments of the invention, the first polymer blend and the second polymer blend can be extruded and / or melt-spun at one or more of the elevated temperatures or temperature ranges mentioned above. In some embodiments of the invention, the first polymer blend and the second polymer blend can be extruded and melt-spun at the same elevated temperature.

[0057] According to certain embodiments of the invention, the step of consolidating multiple bicomponent fibers or multiple crimped bicomponent fibers may include thermal bonding, ultrasonic bonding, mechanical bonding, adhesive bonding, or any combination thereof. The consolidation step may, for example, include forming multiple individual bonding points by thermal bonding or ultrasonic bonding. In this respect, the multiple individual bonding sites define a bonding area. For example, the bonding area may comprise from about 3% to about 30% of the nonwoven fabric, for example at least about any one of the following: 3, 4, 5, 6, 8, 10, 12, 14, and 15%, and / or at most about any one of the following: 30, 28, 26, 25, 24, 22, 20, 18, 16, and 15%. Alternatively, the step of forming multiple individual adhesive portions may be performed at a temperature of about 120°C to about 170°C, for example at least about any of the following: 120, 122, 124, 125, 126, 128, 130, 132, 134 and 135°C, and / or at most about any of the following: 170, 160, 150, 148, 146, 145, 144, 142, 140, 138, 136 and 135°C.

[0058] In another aspect, the present invention provides an article comprising one or more nonwoven fabrics as described and disclosed herein. This article may include adult diapers, baby diapers, pull-ups, and feminine hygiene pads. According to certain embodiments of the invention, the article may include a top sheet comprising a nonwoven fabric as described and disclosed herein.

[0059] Example

[0060] This disclosure is further illustrated by the following embodiments and should in no way be construed as limiting. That is, the specific features described in the following embodiments are merely illustrative and not limiting.

[0061] Instance Group 1

[0062] Nine (9) different crimped bicomponent fibers (i.e., samples 1-9) were prepared, and their mean free crimp lengths were measured. Each bicomponent fiber was a side-by-side bicomponent fiber, wherein the first polymer material accounted for 60 wt% of the bicomponent fiber, and the second polymer material accounted for 40 wt% of the bicomponent fiber. The mean free crimp length of each different crimped bicomponent fiber was measured. The results are summarized in Table 1 below.

[0063] Sample 1 is a control sample. All polymer materials consist of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). For Sample 2, the first polymer material consists of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymer material consists of 100 wt% polypropylene copolymer, purchased as SV956 from LyondellBasell.

[0064] For Sample 3, the first polymer material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) which had an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymer material consists of a blend of the following substances: (i) 80 wt% of polypropylene homopolymer (i.e., PP3155E5, purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg); (ii) 15 wt% of linear low-density polyethylene (i.e., PE-Dowlex 2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (190°C / 2.16 kg); and (iii) 5 wt% of EP-iPP diblock polymer (i.e., IntuneTM–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg).

[0065] For sample 4, the first polymer material consists of a blend of the following substances: (i) 97 wt% of polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg) and (ii) 3 wt% of meltblown polypropylene having an MFR of 500 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg). The second polymer material consists of a blend of the following substances: (i) 80 wt% of polypropylene homopolymer (i.e., PP3155E5, purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg); (ii) 15 wt% of linear low-density polyethylene (i.e., PE-Dowlex2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (190°C / 2.16 kg); and (iii) 5 wt% of EP-iPP diblock polymer (i.e., IntuneTM–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg).

[0066] For Sample 5, the first polymer material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymer material consisted of 100 wt% polypropylene random copolymer, which was commercially available as RP448S from LyondellBasell.

[0067] For Sample 6, the first polymer material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymer material consisted of 100 wt% polypropylene copolymer, purchased from LyondellBasell as Pro-Fax SDS242.

[0068] For Sample 7, the first polymer material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymer material consisted of 97 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) and 3 wt% Dowlex polyethylene, which also had an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg).

[0069] For Sample 8, the first polymer material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymer material consisted of: (i) 92 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg); (ii) 6 wt% Dowlex polyethylene; and (iii) 2 wt% EP-iPP diblock polymer (i.e., Intune™–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg).

[0070] For Sample 9, the first polymeric material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymeric material consisted of: (i) 86.5 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg); (ii) 10 wt% Dowlex polyethylene; and (iii) 3.5 wt% EP-iPP diblock polymer (i.e., Intune™–Dow D5545) having an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg).

[0071] As shown in Table 1, Sample 3 provides a mean free crimp length when using a blend of polypropylene, polyethylene, and a small amount of compatibilizer. In this respect, the improved mean free crimp achieved by Sample 3 is realized when using a significantly smaller amount of polypropylene copolymer. Details regarding the specific composition of the first and second polymer materials for each sample are summarized more concisely in Table 2.

[0072] Instance Group 2

[0073] Thirteen (13) additional different crimped bicomponent fibers (i.e., samples 10-22) were prepared, and their mean free crimp lengths were measured. For these samples, each bicomponent fiber was a side-by-side bicomponent fiber, but the respective weight percentages of the first and second polymer materials of the bicomponent fibers varied as shown in Table 2. The mean free crimp length of each different crimped bicomponent fiber was measured. The results are summarized in Table 1 below.

[0074] For Sample 10, the first polymer material consisted of 100% by weight of polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymer material consists of: 80 wt% polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), 15 wt% Dowlex polyethylene (i.e., PE-Dowlex2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), and 5 wt% EP-iPP diblock polymer (i.e., IntuneTM–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The first polymer material constitutes 70 wt% of the bicomponent fiber, while the second polymer material constitutes 30 wt% of the bicomponent fiber.

[0075] For sample 11, the first and second polymer materials are the same as those in sample 10. However, for sample 11, the first polymer material accounts for 50 wt% of the bicomponent fiber, while the second polymer material accounts for 50 wt% of the bicomponent fiber.

[0076] For sample 12, the first and second polymer materials are the same as those in sample 10. However, for sample 12, the first polymer material accounts for 30 wt% of the bicomponent fiber, while the second polymer material accounts for 70 wt% of the bicomponent fiber.

[0077] For Sample 13, the first polymer material consists of a blend of the following: (i) 97 wt% of polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg), and (ii) 3 wt% of meltblown polypropylene having an MFR of 1800 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg). The second polymer material consists of a blend of the following substances: (i) 80 wt% of polypropylene homopolymer (i.e., PP3155E5, purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg); (ii) 15 wt% of linear low-density polyethylene (i.e., PE-Dowlex2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (190°C / 2.16 kg); and (iii) 5 wt% of EP-iPP diblock polymer (i.e., IntuneTM–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The first polymer material constitutes 70 wt% of the bicomponent fiber, while the second polymer material constitutes 30 wt% of the bicomponent fiber.

[0078] For sample 14, the first and second polymer materials are the same as those in sample 13. However, for sample 14, the first polymer material accounts for 50 wt% of the bicomponent fiber, while the second polymer material accounts for 50 wt% of the bicomponent fiber.

[0079] For sample 15, the first and second polymer materials are the same as those in sample 13. However, for sample 15, the first polymer material accounts for 30 wt% of the bicomponent fiber, while the second polymer material accounts for 70 wt% of the bicomponent fiber.

[0080] For Sample 16, the first polymeric material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymeric material consisted of a blend of the following: (i) 77 wt% polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg); (ii) 15 wt% linear low-density polyethylene (i.e., PE-Dowlex 2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (190°C / 2.16 kg); and (iii) 5 wt% EP-iPP diblock polymer (i.e., Intune™–Dow). (d5545) has an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg) and (iv) 3 wt% meltblown polypropylene having an MFR of 1800 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The first polymer material constitutes 70 wt% of the bicomponent fiber, while the second polymer material constitutes 30 wt% of the bicomponent fiber.

[0081] For sample 17, the first and second polymer materials are the same as those in sample 16. However, for sample 16, the first polymer material accounts for 50 wt% of the bicomponent fiber, while the second polymer material accounts for 50 wt% of the bicomponent fiber.

[0082] For sample 18, the first and second polymer materials are the same as those in sample 16. However, for sample 18, the first polymer material accounts for 30 wt% of the bicomponent fiber, while the second polymer material accounts for 70 wt% of the bicomponent fiber.

[0083] For Sample 19, the first polymer material consists of a blend of the following: (i) 99 wt% of polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg), and (ii) 1 wt% of meltblown polypropylene having an MFR of 1800 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg). The second polymer material consists of a blend of the following substances: (i) 80 wt% polypropylene homopolymer (i.e., PP3155E5, purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), (ii) 15 wt% Dowlex polyethylene (i.e., PE-Dowlex 2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), and (iii) 5 wt% EP-iPP diblock polymer (i.e., IntuneTM–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The first polymer material constitutes 50 wt% of the bicomponent fiber, and the second polymer material constitutes 50 wt% of the bicomponent fiber.

[0084] For sample 20, the first polymer material consists of a blend of the following: (i) 98 wt% of polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg), and (ii) 2 wt% of meltblown polypropylene having an MFR of 1800 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg). The second polymer material consists of a blend of the following substances: (i) 80 wt% polypropylene homopolymer (i.e., PP3155E5, purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), (ii) 15 wt% Dowlex polyethylene (i.e., PE-Dowlex 2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), and (iii) 5 wt% EP-iPP diblock polymer (i.e., IntuneTM–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The first polymer material constitutes 50 wt% of the bicomponent fiber, and the second polymer material constitutes 50 wt% of the bicomponent fiber.

[0085] For sample 21, the first polymer material consists of a blend of the following: (i) 97 wt% of polypropylene homopolymer (i.e., PP3155E5 purchased from Exxon) having an MFR of 36 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg), and (ii) 3 wt% of meltblown polypropylene having an MFR of 1800 g / 10 min according to ASTM D1238 (230 °C / 2.16 kg). The second polymer material consists of a blend of the following substances: (i) 82 wt% polypropylene homopolymer (i.e., PP3155E5, purchased from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), (ii) 15 wt% Dowlex polyethylene (i.e., PE-Dowlex 2036.01G, purchased from Dow) with an MFR of 2.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg), and (iii) 3 wt% EP-iPP diblock polymer (i.e., IntuneTM–Dow D5545) with an MFR of 9.5 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The first polymer material constitutes 50 wt% of the bicomponent fiber, and the second polymer material constitutes 50 wt% of the bicomponent fiber.

[0086] For Sample 22, the first polymeric material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The second polymeric material consisted of 100 wt% polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM D1238 (230°C / 2.16 kg). The first polymeric material comprised 50 wt% of the bicomponent fiber, and the second polymeric material comprised 50 wt% of the bicomponent fiber.

[0087]

[0088] Table 1

[0089]

[0090]

[0091] These and other modifications and variations can be made to the invention by those skilled in the art without departing from the spirit and scope of the invention, which is more specifically set forth in the appended claims. Furthermore, it should be understood that aspects of the various embodiments can be interchanged, in whole or in part. Moreover, those skilled in the art will understand that the foregoing description is merely exemplary and is not intended to limit the invention as further described in these appended claims. Therefore, the spirit and scope of the appended claims should not be limited to the exemplary descriptions of the versions contained herein.

Claims

1. A high-loft nonwoven fabric comprising a plurality of crimped bicomponent fibers having a first component comprising a first polymer material and a second component comprising a second polymer material, the first polymer material comprising a first polymer or a first polymer blend, wherein the second polymer material comprises a second polymer blend of: (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer having an MFR of 1 to 15 g / 10 min as determined by ASTM D1238 (190°C / 2.16 kg), and (iii) at least one compatibilizer comprising at least one polypropylene-polyethylene copolymer.

2. The high-loft nonwoven fabric according to claim 1, wherein, The first polymer material includes polyolefins.

3. The high-loft nonwoven fabric according to claim 1, wherein, The first polymer material includes one or more polypropylenes, one or more polyethylenes, or any combination thereof.

4. The high-loft nonwoven fabric according to claim 1, wherein, The first polymer material comprises a first polypropylene having a first MFR and a second polypropylene having a second MFR; wherein the second MFR is equal to or greater than the first MFR.

5. The high-loft nonwoven fabric according to claim 4, wherein, The ratio between the second MFR and the first MFR is at least any one of the following: 1:1, 1.2:1, 1.4:1, 1.5:1, 1.6:1, 1.8:1, 2:1, 4:1, 5:1, 6:1, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, 22:1, 24:1 and 25:1, or at most any one of the following: 60:1, 55:1, 50:1, 48:1, 46:1, 45:1, 44:1, 42:1, 40:1, 38:1, 36:1, 35:1, 34:1, 32:1, 30:1, 28:1, 26:1 and 25:

1.

6. The high-loft nonwoven fabric according to claim 4 or 5, wherein, The first polymer material comprises a first polypropylene in a proportion of at least any one of the following: 70, 75, 80, 85 and 90 wt%, or at most any one of the following: 99, 98, 97, 96, 95, 94, 93, 92, 91 and 90 wt%; and wherein the first polymer material comprises a second polypropylene in a proportion of at least any one of the following: 1, 2, 3, 4 and 5 wt%, or at most any one of the following: 10, 9, 8, 7, 6 and 5 wt%.

7. The high-loft nonwoven fabric according to any one of claims 1 to 5, wherein, The second polymer blend comprises 60 to 90 wt% of at least one polypropylene polymer, 5 to 30 wt% of at least one polyethylene polymer, and 1 to 10 wt% of at least one polypropylene-polyethylene copolymer.

8. The high-loft nonwoven fabric according to claim 7, wherein, The at least one polypropylene polymer is a first polypropylene polymer and has an MFR of 10 to 100 g / 10 min as determined by ASTM D1238 (230°C / 2.16 kg), the at least one polyethylene polymer is a first polyethylene polymer and has an MFR of 1 to 40 g / 10 min as determined by ASTM D1238 (190°C / 2.16 kg), and the at least one polypropylene-polyethylene copolymer is a first polypropylene-polyethylene copolymer and has an MFR of 0.5 to 20 g / 10 min as determined by ASTM D1238 (230°C / 2.16 kg).

9. The high-loft nonwoven fabric according to claim 8, wherein, The at least one polypropylene-polyethylene copolymer is an EP-iPP diblock polymer.

10. The high-loft nonwoven fabric according to claim 8, wherein, The first polypropylene-polyethylene copolymer has an ethylene monomer content of at least any one of the following: 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 26, 38, 40, 42, 44 and 45 wt%, or at most any one of the following: 60, 58, 56, 55, 54, 52, 50, 48, 46 and 45 wt%.

11. The high-loft nonwoven fabric according to any one of claims 1 to 5, wherein, The plurality of crimped bicomponent fibers comprise continuous fibers.

12. The high-loft nonwoven fabric according to any one of claims 1 to 5, wherein, The plurality of crimped bicomponent fibers include spunbond fibers, staple fibers, or combinations thereof.

13. The high-loft nonwoven fabric according to any one of claims 1 to 5, wherein, The plurality of crimped bicomponent fibers include side-by-side configurations, sheath / core configurations, disc configurations, island configurations, multileaf configurations, or any combination thereof.

14. The high-loft nonwoven fabric according to any one of claims 1 to 5, wherein, The first polymer material comprises at least any one of the following percentages of the plurality of crimped bicomponent fibers: 20, 25, 30, 35, 40, 45, 50, and 55 wt%, or at most any one of the following percentages: 80, 75, 70, 65, 60, and 55 wt%, and the second polymer material comprises at least any one of the following percentages of the plurality of crimped bicomponent fibers: 20, 25, 30, 35, 40, 45, 50, and 55 wt%, or at most any one of the following percentages: 80, 75, 70, 65, 60, and 55 wt%.

15. The high-loft nonwoven fabric according to any one of claims 1 to 5, wherein, The plurality of crimped bicomponent fibers define a first nonwoven layer, and the high-loft nonwoven fabric further includes one or more additional nonwoven layers, the additional nonwoven layers including at least a second nonwoven layer, and the one or more additional nonwoven layers including a spunbond layer, a meltblown layer, a carded layer, a hydroentangled layer, a cellulose layer, or any combination thereof.

16. The high-loft nonwoven fabric according to claim 15, wherein, The high-loft nonwoven fabric includes one or more cellulose layers located directly or indirectly between the first nonwoven layer and the second nonwoven layer, wherein the second nonwoven layer includes a spunbond layer or a spunbond-meltblown-spunbond layer.

17. The high-loft nonwoven fabric according to claim 1, wherein, The at least one compatibilizer is composed of at least one polypropylene-polyethylene copolymer.

18. A method for manufacturing a high-loft nonwoven fabric, comprising: (a) Forming a first polymer melt comprising a first polymer or a blend of the first polymer; (b) Forming a second polymer melt comprising (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer having an MFR of 1 to 15 g / 10 min as determined by ASTM D1238 (190°C / 2.16 kg), and (iii) at least one second polymer blend comprising a compatibilizer of a polypropylene-polyethylene copolymer. (c) Forming multiple bicomponent fibers by melt spinning the first polymer melt and the second polymer melt using a bicomponent spinneret assembly; (d) Before or during deposition on the collection surface, the plurality of bicomponent fibers are crimped or subjected to a crimping operation to provide a plurality of crimped bicomponent fibers; as well as (e) Consolidate the plurality of crimped bicomponent fibers to form a high-loft nonwoven fabric according to any one of claims 1 to 17.

19. A method for manufacturing a high-loft nonwoven fabric, comprising: (a) Forming a first polymer melt comprising a first polymer or a blend of the first polymer; (b) Forming a second polymer melt comprising (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer having an MFR of 1 to 15 g / 10 min as determined by ASTM D1238 (190°C / 2.16 kg), and (iii) at least one second polymer blend comprising a compatibilizer of a polypropylene-polyethylene copolymer. (c) Forming multiple bicomponent fibers by melt spinning the first polymer melt and the second polymer melt using a bicomponent spinneret assembly; (d) Consolidate the plurality of bicomponent fibers to form an intermediate nonwoven fabric; as well as (e) subjecting the plurality of bicomponent fibers of the intermediate nonwoven fabric to a crimping operation to provide a high-loft nonwoven fabric according to any one of claims 1 to 17.

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