High-loft nonwoven fabric

Abstract

Nonwoven fabric is provided. [Solution] These include a plurality of crimped bicomponent fibers having a first component comprising a first polymer material comprising a first polymer or a first polymer blend and a second component comprising a second polymer material, 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 compatibleizer comprising or consisting of at least one polypropylene-polyethylene copolymer.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63 / 256,796, filed Oct. 18, 2021, which is hereby incorporated by reference in its entirety.

[0002] Embodiments of the invention disclosed herein generally relate to a non - woven fabric having a plurality of crimped bicomponent fibers having a first component including a first polymer material including a first polymer or a first polymer blend and a second component including a second polymer material. In this regard, the second polymer material includes a second polymer blend including (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 Art

[0003] In non - woven fabrics, the fibers forming the non - woven fabric are generally oriented within the x - y plane of the web. Thus, the resulting non - woven fabric is relatively thin and lacks loft or significant thickness in the z - direction. Loft or thickness of non - woven fabrics suitable for use in hygiene - related molded articles (e.g., personal care absorbents) promotes user comfort (softness), management of overflow, and fluid distribution to adjacent components of the molded article. In this regard, high - loft, low - density non - woven fabrics are used for various end - use applications, such as in hygiene - related products (e.g., menstrual pads and napkins, disposable diapers, urine leakage care pads, etc.). High - loft and low - density non - woven fabrics can be used in products such as towels, industrial wipes, urine leakage products, infant care products (e.g., diapers), female absorbent care products, and commercial healthcare molded articles.

Summary of the Invention

[0004] This invention was made to solve the problems of the above-mentioned conventional technology. [Means for solving the problem]

[0005] One or more embodiments of the present invention can address one or more of the aforementioned problems. One embodiment according to the present invention provides a nonwoven fabric comprising a plurality of crimped bicomponent fibers having a first component comprising a first polymer material comprising a first polymer material comprising a first polymer blend comprising a first polymer material comprising a first polymer blend comprising a first polymer material comprising a first polymer blend comprising a first polymer material comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer blend comprising a first polymer material comprising a first polymer blend comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer material comprising a first polymer blend

[0006] In another embodiment, the present invention provides a method for producing a nonwoven fabric. The method may include: (a) forming a first polymer melt comprising a first polymer or a first polymer blend; (b) forming a second polymer melt comprising a second polymer blend comprising (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibleizer comprising a polypropylene-polyethylene copolymer; (c) forming a plurality of bicomponent fibers by melt spinning the first and second polymer melts through a bicomponent spinneret pack; (d) providing a plurality of crimped bicomponent fibers by allowing the plurality of bicomponent fibers to crimp prior to or during deposition on an accumulation surface, or by subjecting the plurality of bicomponent fibers to a crimping process; and (e) consolidating the plurality of crimped bicomponent fibers to form a nonwoven fabric.

[0007] In another embodiment, the present invention provides a method for producing a nonwoven fabric. The method may include: (a) forming a first polymer melt comprising a first polymer or a first polymer blend; (b) forming a second polymer melt comprising a second polymer blend comprising (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibleizer comprising a polypropylene-polyethylene copolymer; (c) forming a plurality of bicomponent fibers by melt spinning the first and second polymer melts through a bicomponent spinneret pack; (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 process to provide a nonwoven fabric.

[0008] In yet another embodiment, the present invention provides a molded article comprising one or more nonwoven fabrics as described and disclosed herein. The molded article may include adult diapers, baby diapers, pull-ups, or feminine hygiene pads. According to certain embodiments of the present invention, the molded article may include a top sheet comprising a nonwoven fabric as described and disclosed herein.

[0009] Hereafter, the present invention will be described in more detail with reference to the accompanying drawings. Here, only a few embodiments of the present invention are shown, not all of them. In fact, the present invention can be carried out in many different forms. It should not be construed as being limited to the embodiments shown herein. Rather, these embodiments are provided so that this disclosure satisfies applicable legal requirements. The class numbers consistently refer to elements of the same class. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 illustrates a crimped bicomponent fiber according to one embodiment of the present invention. [Figure 2]Figures 2A to 2H illustrate examples of cross-sectional images of bicomponent fibers according to certain embodiments of the present invention. [Modes for carrying out the invention]

[0011] Hereafter, the present invention will be described in more detail with reference to the accompanying drawings. In this, only some embodiments of the present invention will be shown, not all of them. In fact, the present invention can be carried out in many different forms. It should not be construed as being limited to the embodiments shown herein. Rather, these embodiments are provided so that this disclosure satisfies applicable legal requirements. The singular forms “a,” “an,” and “the” used herein and in the appended claims encompass multiple subjects unless the context clearly states otherwise.

[0012] The terms “substantial” or “substantially” may include a predetermined total amount according to certain embodiments of the present invention, or, according to other embodiments of the present invention, an approximate amount (e.g., 95%, 96%, 97%, 98%, or 99% of the predetermined total amount).

[0013] The terms "polymer" or "polymeric," as used interchangeably herein, may include homopolymers, copolymers, such as block, graft, random, and alternating copolymers, terpolymers, etc., as well as blends and modifications thereof. Furthermore, unless specifically otherwise limited, the terms "polymer" or "polymeric" encompass all possible structural isomers, without limitation geometric isomers, optical isomers, or stereoisomers including enantiomers, and / or any chiral molecular configuration of such polymers or polymeric materials. These configurations include, but are not limited to, isotactic, syndiotactic, and atactic configurations of such polymers or polymeric materials. The terms "polymer" or "polymeric" also encompass polymers made from various catalyst systems, without limitation, including Ziegler-Natta catalyst systems and metallocene / single-site catalyst systems. The terms "polymer" or "polymeric," according to certain embodiments of the present invention, also include polymers produced by fermentation processes or that are biosourced.

[0014] As used herein, the terms “nonwoven fabric” and “nonwoven web” may include a web having a structure of individual fibers, filaments, and / or yarns that are overlapped with each other in an identifiable, repeating manner, rather than in a knitted or woven fabric. Nonwoven fabrics or webs according to certain embodiments of the present invention may be formed by any process conventionally known in the art, such as, for example, a melt-blown process, a spunbond process, a needle-punching process, a water-flow entanglement process, an air-laid process, and a bonded carding web process. As used herein, a “nonwoven web” may include a plurality of individual fibers that have not been subjected to a consolidation process.

[0015] As used herein, the terms “fabric” and “nonwoven fabric” may include a web of fibers in which multiple fibers are mechanically entangled, connected to each other, fused together, and / or chemically joined together. For example, a nonwoven web of individually layered fibers may be subjected to a joining or consolidation process to join at least some portions of the individual fibers together to form a web of interconnected fibers that are tightly packed together (e.g., integrated).

[0016] As used herein, the terms “consolidated” and “consolidation” may include bringing at least some portions of the fibers of a nonwoven web closer together or attaching them together to form a joint(s) (e.g., heat-sealing, chemically joining, and / or mechanically entanglement). These serve to increase the resistance to external forces (e.g., abrasion and tensile forces) compared to an unconsolidated web. A joint(s) may include, for example, discrete or localized areas of the web material that have been softened or melted and optionally subsequently or simultaneously compressed to form discrete or localized deformations of the web material. Furthermore, the term “consolidation” may include an entire nonwoven web that has been treated, for example, by thermal bonding or mechanical entanglement (e.g., water entanglement), in which at least some portion of the fibers are brought to closer proximity or between them (e.g., heat-sealed together, chemically bonded together, and / or mechanically entangled together). Such a web may be considered, according to certain embodiments of the present invention, a “consolidated nonwoven,” a “nonwoven fabric,” or simply a “fabric.”

[0017] As used herein, the term "staple fiber" may include fibers cut from a filament. According to certain embodiments, any type of filament material may be used to form staple fibers. For example, staple fibers may be formed from polymer fibers and / or elastomer fibers. Examples of materials, not limited to these, may include polyolefins (e.g., polypropylene or polypropylene-containing copolymers), polyethylene terephthalate, and polyamides. The average length of staple fibers may range, for example only, from about 2 centimeters to about 15 centimeters.

[0018] As used herein, the term "spunbond" may include fibers formed by extruding molten thermoplastic material as filaments from multiple thin, usually circular, capillaries of a spinaret, the diameter of which is rapidly reduced. According to certain embodiments of the present invention, spunbond fibers are generally not tacky when they accumulate on an aggregate surface and may generally be continuous as described and disclosed herein. It should be noted that spunbond used in certain types of composites of the present invention may include nonwoven fabrics described in the literature as SPINLACE®. Spunbond fibers may include, for example, continuous fibers.

[0019] As used herein, the term “continuous fibers” refers to fibers that are not cut from their original length prior to being formed into a nonwoven web or nonwoven fabric. Continuous fibers may have an average length ranging from about 15 centimeters to more than 1 meter, up to the length of the web or fabric to be formed. For example, continuous fibers as used herein may include fibers whose length is at least 1,000 times longer than the average diameter of the fibers. For example, the length of the fibers may be at least about 5,000, 10,000, 50,000, or 100,000 times greater than the average diameter of the fibers.

[0020] As used herein, the term “meltblown” may include fibers formed by extruding molten thermoplastic material through a plurality of thin die-capillaries as molten threads or filaments into a convergent, high-speed, usually high-temperature gas (e.g., air) flow that thins the filaments of molten thermoplastic material and reduces their diameter. According to certain embodiments of the present invention, this may be microfiber in diameter. According to certain embodiments of the present invention, the die-capillaries may be circular. The meltblown fibers are then carried by the high-speed gas flow and accumulate on an accumulation surface, forming a web of randomly distributed meltblown fibers. The meltblown fibers may include microfibers that are continuous or discontinuous and are generally sticky when accumulated on an accumulation surface. However, meltblown fibers are shorter in length than spunbond fibers.

[0021] As used herein, the term "layer" may include a generally recognized combination of similar material types and / or functions existing in the XY plane.

[0022] As used herein, the term "multicomponent fiber" can include fibers formed from at least two different polymer materials (e.g., two or more) that are extruded from separate extruders but spun together to form one fiber. As used herein, the term "bicomponent fiber" can include fibers formed from two different polymer materials that are extruded from separate extruders but spun together to form one fiber. The polymer materials or polymers are disposed at substantially fixed positions in distinct zones on the cross-section of the multicomponent fiber and extend continuously along the length of the multicomponent fiber. Such a configuration of the multicomponent fiber can be, for example, a sheath / core configuration where one polymer is surrounded by another, a sheath component and a core component that define at least a portion of the outer surface of a bicomponent fiber having an eccentric sheath-core configuration, an eccentric sheath-core configuration that includes a sheath component and a core component that define at least a portion of the outer surface of a bicomponent fiber having an eccentric sheath-core configuration, or a side-by-side configuration, or a pie configuration, or an "island-in-the-sea" configuration, which are known in the field of multicomponent fibers that each include a bicomponent fiber.

[0023] As used herein, the term "monocomponent fiber" can include fibers formed from a single polymer or polymer blend (e.g., a blend or mixture of two or more polymers) that is extruded from a single extruder. The single polymer or polymer blend can define, for example, a polymer matrix in which one or more additives (e.g., fillers) can be dispersed.

[0024] As used herein, the term "high loft" includes materials that can generally have a z-direction thickness exceeding about 0.3 mm and a relatively low bulk density. The thickness of the "high loft" nonwoven fabric and / or layer 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). It is determined using a ProGage thickness tester (Model 89-2009) available from Thwig-Albert Instrument (West Berlin, New Jersey 08091), which utilizes a 2" diameter foot with an applied force of 1.45 kPa during measurement. According to certain embodiments of the present invention, the thickness of the "high loft" nonwoven fabric and / or layer can be at most about any 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 of the following: 0.3, 0.4, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, and 2.0 mm. Additionally, the "high loft" nonwoven fabric and / or layer used herein has a relatively low density (e.g., the bulk density of the weight per unit volume), e.g., less than about 3 60 kg / m 3 , e.g., at most about any of the following: 70, 60, 55, 50, 45, 40, 35, 30, and 25 kg / m 3 and / or at least about any of the following: 10, 15, 20, 25, 30, 35, 40, 45, 50, and 55 kg / m 3 can have.

[0025] As used herein, the term "machine direction" or "MD" includes the direction in which the fabric is produced or conveyed. As used herein, the term "cross direction" or "CD" includes the direction of the fabric that is substantially perpendicular to the MD.

[0026] As used herein, the term "aspect ratio" includes the ratio of the length of the long axis to the length of the short axis of the cross-section of the fiber in question.

[0027] All integer endpoints disclosed herein that can produce smaller ranges within a given range disclosed herein are within the scope of certain embodiments of the invention. For example, the disclosure of about 10 to about 15 includes disclosures of intermediate ranges, such as about 10 to about 11, about 10 to about 12, about 13 to about 15, about 14 to about 15, etc. Furthermore, all single decimal endpoints (e.g., numbers reported to one decimal place after rounding) that can produce smaller ranges within a given range disclosed herein are within the scope of certain embodiments of the invention. For example, the disclosure of about 1.5 to about 2.0 includes disclosures of 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, etc.

[0028] In one embodiment, the present invention provides a nonwoven fabric comprising a plurality of crimped bicomponent fibers, each comprising a first component comprising a first polymer material comprising a first polymer or a first polymer blend, and a second component comprising a second polymer material, 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 polypropylene-polyethylene copolymer or at least one compatibleizer comprising the same. According to certain embodiments of the present 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 width and flow directions of the nonwoven fabric).

[0029] Figure 1 illustrates, for example, a crimped bicomponent fiber 50 according to a certain embodiment of the present invention. In this, the crimped bicomponent fiber 50 comprises a plurality of three-dimensional coil or helical crimped portions. While the crimped bicomponent fiber 50 in Figure 1 illustrates a plurality of three-dimensional coil or helical crimped portions, the crimped bicomponent fiber may also or alternatively comprise at least one discrete zigzag crimped portion, at least one discrete helical crimped portion, or a combination thereof.

[0030] According to certain embodiments of the present invention, a plurality of crimped bicomponent fibers may include average free-state crimp percentages ranging from about 30% to about 300%, for example, up to about any of the following: 300, 275, 250, 225, 200, 175, 150, 125, 100, and 75%, and / or at least any of the following: 20, 30, 40, 50, 75, 100, 125, 150, 175, and 200%. In addition or alternatively, multiple crimped bicomponent fibers include average free-state crimp lengths ranging from approximately 10 mm to approximately 50 mm, for example, at least approximately one of the following: 10, 12, 14, 15, 16, 18, 20, 22, 24, and 25 mm, and / or at most approximately one of the following: 50, 45, 40, 38, 35, 32, 30, 28, and 25 mm. The average free-state crimp percentage can be determined by determining the free-state crimp length of the fiber in question using an Instron 5565 equipped with a 2.5 N load cell. In this regard, a free-state or unstretched fiber bundle can be mounted in a clamp of the machine. The free-state crimp length can be measured at the point where the load on the fiber bundle (e.g., a 2.5 N load cell) becomes constant. The following parameters are used to determine the free state crimp length: (i) the approximate free state fiber bundle weight is recorded in grams (e.g., xxx g ± 0.002 g), (ii) the unstretched bundle length is recorded in inches, (iii) the Inston gauge length (i.e., the distance or gap between the clamps that grip the fiber bundle) is set to 1 inch, and (iv) the crosshead speed is set to 2.4 inches / min. The free state crimp length of the fiber in question can then be determined by recording the elongated length of the fiber at the point where the load becomes constant (i.e., the fiber is fully extended). The average free state crimp percentage can be calculated from the free state crimp length and the unstretched fiber bundle length (e.g., gauge length) of the fiber in question. For example, a measured free-state crimp length of 32 mm would provide an average free-state crimp percentage of approximately 126% when using the 1-inch (25.4 mm) gauge length discussed above. The aforementioned method for determining the average free-state crimp percentage may be particularly useful when evaluating continuous fibers with helical coil crimp.For example, conventional textile fibers can be mechanically crimped and measured optically, but continuous fibers with helical coil crimping sections will cause errors when attempting to optically count the "crimping" of such fibers.

[0031] According to certain embodiments of the present invention, a plurality of crimped bicomponent fibers may comprise a plurality of three-dimensional crimped portions having an average diameter of about 0.5 mm to about 5 mm (for example, based on the average of the longest lengths defining each individual crimped portion). For example, at most about any 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 of the following: 0.5, 0.6, 0.07, 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 verified by examining a sample of multi-component fiber and using a digital optical microscope (manufactured by Hirox Co., Ltd., Japan, KH-7700) to obtain digital measurements of the loop diameter of the three-dimensional crimped portions of the SMF. Generally, a magnification range of 20 × to 40 × can be used to facilitate evaluation of the loop diameter formed from the three-dimensional crimping of the multi-component fiber.

[0032] According to certain embodiments of the present invention, a plurality of crimped bicomponent fibers may include a plurality of three-dimensional crimped portions having an average diameter of about 10 mm to about 40 mm (for example, based on the average of the longest lengths defining each individual crimped portion). For example, at most 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 present invention, the average diameter of the plurality of three-dimensional crimped portions may be determined by the use of a digital optical microscope (manufactured by Hirox Co., Ltd., Japan, KH-7700) to examine a sample of the multicomponent fiber and obtain a digital measurement of the loop diameter of the three-dimensional crimped portions of the SMF. Generally, a magnification range of 20× to 40× can be used to facilitate the evaluation of loop diameters formed from the three-dimensional crimping of multi-component fibers.

[0033] According to certain embodiments of the present invention, the first polymer material may comprise polyolefins, for example, one or more polypropylenes, one or more polyethylenes, or any combination thereof. For example, the first polymer material may comprise a single polymer or a total polymer content attributable to a first polymer blend comprising, 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 greater than or equal to the first MFR. According to certain embodiments of the present 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.

[0034] According to certain embodiments of the present invention, the first polymer material may comprise about 70 wt.% to about 99 wt.% of a first polypropylene, for example, at least about any of the following: 70, 75, 80, 85, and 90 wt.%, and / or up to about any of the following: 99, 98, 97, 96, 95, 94, 93, 92, 91, and 90 wt.%. In addition 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 of the following: 1, 2, 3, 4, and 5 wt.%, and / or up to about any of the following: 10, 9, 8, 7, 6, and 5 wt.%.

[0035] According to certain embodiments of the present invention, the first polypropylene of the first polymer material may have an MFR (i.e., first MFR) ranging from 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 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 of the following: 100, 90, 80, 70, 60, 50, and 40 g / 10 min as determined by ASTM-D1238 (230 C° / 2.16 kg). In addition or alternatively, the second polypropylene of the first polymer material may have an MFR (i.e., second MFR) ranging 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 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 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).

[0036] According to certain embodiments of the present invention, the second polymer blend may comprise at least one polypropylene polymer (e.g., a single polypropylene polymer or a combination of polypropylene polymers) in an amount ranging from about 60 wt.% to about 90 wt.%, for example, at least one polypropylene polymer in any of the following amounts: 60, 62, 64, 65, 66, 68, 70, 72, 74, 77, 78, and 80 wt.%, and / or at most one polypropylene polymer in any of the following amounts: 90, 88, 86, 85, 84, 83, 82, 81, and 80 wt.%. For example, the at least one polypropylene polymer may be a first polypropylene polymer that is the same as or different from the first polypropylene used in the first polymer blend, and / or a second polypropylene polymer that is the same as or different from the second polypropylene used in the first polymer blend. According to certain embodiments of the present invention, at least one polypropylene polymer (e.g., a single polypropylene polymer or a combination of polypropylene polymers) of the second polymer blend has 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, It may have 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 up to approximately 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 contain several different polypropylene polymers, and the weight-average MFR of a combination of several different polypropylene polymers may fall within any of the aforementioned ranges.

[0037] According to certain embodiments of the present invention, the second polymer blend may comprise at least one polyethylene polymer in about 5 to about 30 wt.% of any one of the following, for example, at least one polyethylene polymer in about any one of the following: 5, 6, 8, 10, 12, 14, and 15 wt.%, and / or at most one polyethylene polymer in about any one of the following: 30, 28, 26, 25, 24, 22, 20, 18, 16, and 15 wt.%, for example, the at least one polyethylene polymer may be the first polyethylene polymer. According to certain embodiments of the present invention, 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 of the following: 1, 2, 4, 5, 6, 8, 10, 12, 14, and 15 g / 10 min, and / or at most about any of the following: 40, 35, 30, 25, 20, 18, 16, and 15 g / 10 min.

[0038] According to certain embodiments of the present invention, the second polymer blend may comprise at least one polypropylene-polyethylene copolymer (e.g., a compatible agent) in about 1 wt.% to about 10 wt.%, for example, at least one polypropylene-polyethylene copolymer in any of the following amounts: 1, 2, 3, 4, and 5 wt.%, and / or at most one polypropylene-polyethylene copolymer in any of the following amounts: 10, 9, 8, 7, 6, and 5 wt.%. The at least one polypropylene-polyethylene copolymer may be, for example, a first polypropylene-polyethylene copolymer (e.g., a single polypropylene-polyethylene copolymer). The first polypropylene-polyethylene copolymer may comprise a first block copolymer or a first random copolymer. According to certain embodiments of the present invention, the first polypropylene-polyethylene copolymer is an EP-iPP diblock polymer.

[0039] A first polypropylene-polyethylene copolymer according to certain embodiments of the present invention may have an ethylene monomer content of about 5 to about 60% by weight, for example, at least about any 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% by weight, and / or up to about any of the following: 60, 58, 56, 55, 54, 52, 50, 48, 46, and 45% by weight. In addition or alternatively, at least one polypropylene-polyethylene copolymer (e.g., the first polypropylene-polyethylene copolymer) has 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 one of the following: ASTM-D1238 (230 C° / 2.16 It may have 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 (kg), and / or at most about any 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 present invention, the second MFR ratio between a third MFR of at least one polypropylene polymer determined by ASTM-D1238 (230°C / 2.16kg) and a fourth MFR of at least one polyethylene polymer determined by ASTM-D1238 (230°C / 2.16kg) may be about 5:1 to about 20:1 in the second polymer material, 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.In addition or alternatively, the second polymer blend may be an MFR of approximately 20 to approximately 120 g / 10 min as determined by ASTM-D1238 (230°C / 2.16 kg), for example, at least approximately one of the following: 20, 22, 24, 25, 26, 28, 30, 32, 34, 35 as determined by ASTM-D1238 (230°C / 2.16 kg) , 36, 38, and 40 g / 10 min, and / or up to approximately any 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).

[0040] In this regard, recent advances in single-site catalysts (e.g., metallocene catalysts) have enabled the creation of various polymer structures that were previously difficult or impossible to produce economically. In this regard, the first polypropylene-polyethylene copolymer may include copolymers formed from single-site catalysts, such as those derived from metallocene catalysts. For example, polymers based on polypropylene with a significant ethylene content can be produced in various configurations (e.g., distinct blocks) to further enhance the copolymer's ability to bridge generally immiscible polymers. Examples of such materials include polypropylene-based elastomers containing propylene and ethylene copolymers, such as Vistamaxx® (e.g., Vistamaxx® 6202). These propylene-based elastomers include, for example, isotactic polypropylene microcrystalline regions and random amorphous regions (e.g., ethylene). Such olefin copolymers may contain hard blocks and soft blocks, where the hard blocks are mainly propylene and the soft blocks are mainly ethylene. In this respect, the hard blocks (e.g., propylene) may constitute 10 to 90% by weight of the copolymer, and the soft blocks may constitute 90 to 10% by weight of the copolymer. In this respect, these copolymers contain a random ethylene distribution on the copolymer. Vistamaxx® copolymer (e.g., Vistamaxx® 6202) is commercially available from ExxonMobil. Vistamaxx® 6202 has a density of 0.862 g / cc, an MI of 9.1 (190°C / 2.16 kg), an MFR of 20 (230°C / 2.16 kg load), and an ethylene content of 15% by weight. Additional examples include olefin diblock copolymers, such as EP-iPP diblock polymers like Intune®. These are polypropylene-based block copolymers containing ethylene monomer.According to certain embodiments of the present invention, the first polypropylene-polyethylene copolymer disclosed herein may be prepared by a process comprising contacting, for example, an addition polymerizable monomer or mixture of monomers with a composition comprising at least one addition polymerization catalyst, a co-catalyst, and a chain shuttle agent ("CSA") under addition polymerization conditions. The process is characterized by the formation of at least some growing polymer chains by two or more reactors operating under steady-state polymerization conditions under distinct process conditions or by two or more zones of a reactor operating under plug-flow polymerization conditions. According to certain embodiments of the present invention, the first polypropylene-polyethylene copolymer may include an olefin block copolymer formed from a single-site catalyst or other catalyst system. In other words, according to certain embodiments of the present invention, the first polypropylene-polyethylene copolymer may not be produced from a single-site catalyst. According to certain embodiments of the present invention, the first polypropylene-polyethylene copolymer lacks acid anhydride functionality, such as maleic anhydride functionality.

[0041] According to certain embodiments of the present invention, copolymers formed from the single-site catalysts discussed above can be distinguished from conventional random copolymers, physical blends of polymers, and block copolymers prepared by sequential monomer addition. These copolymers can be distinguished from random copolymers by features such as a higher melting temperature for an equivalent amount of comonomer and the block composite index described below; from physical blends by features such as a block composite index, better tensile strength, improved fracture strength, finer morphology, improved optics, and greater impact strength at lower temperatures; and from block copolymers prepared by sequential monomer addition by having a molecular weight distribution, rheology, shear thinning, rheological ratio, and block polydispersity.

[0042] As a further example, the first polypropylene-polyethylene copolymer may include an EP-iPP diblock polymer having an ethylene content of 43 to 48% by weight, or 43.5 to 47% by weight, or 44 to 47% by weight, based on the weight of the diblock copolymer. In the example embodiment, the EP-iPP diblock polymer may have a propylene content of 57 to 52% by weight, or 56.5 to 53% by weight, or 56 to 53% by weight, based on the weight of the EP-iPP diblock polymer.

[0043] According to certain embodiments of the present invention, the plurality of crimped bicomponent fibers have an average diameter (e.g., fiber diameter) of about 10 to about 30 microns, for example, at least about any of the following: 10, 12, 14, 15, 16, 18, and 20 microns, and / or at most about any of the following: 30, 28, 26, 25, 24, 22, and 20 microns. In addition or alternatively, the plurality of crimped bicomponent fibers may include continuous fibers, such as spunbond fibers, staple fibers, or a combination thereof.

[0044] According to certain embodiments of the present invention, the plurality of crimped bicomponent fibers may include side-by-side configurations (e.g., circular or non-circular cross-sections), sheath-core configurations, pi configurations, sea-island configurations, multi-lobed configurations, or any combination thereof. For example, a sheath-core configuration may include an eccentric sheath-core configuration encompassing 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 the eccentric sheath-core configuration.

[0045] Figures 2A–2H illustrate examples of cross-sectional views of several non-limiting examples of multiple crimped bicomponent fibers according to certain embodiments of the present invention. As illustrated in Figures 2A–2H, the multiple crimped bicomponent fibers 50 may include, for example, a first polymer component 52 of a first polymer composition A disclosed and described herein, and, for example, a second polymer component 54 of a second polymer composition B disclosed and described herein. The first and second components 52 and 54 may be arranged in substantially specific zones within the cross-section of the multiple crimped bicomponent fibers, extending substantially continuously along the length of the bicomponent fiber. The first and second components 52 and 54 may be arranged side-by-side in fibers with a circular cross-section as shown in Figure 2A, or in fibers with a ribbon-shaped (e.g., non-circular) cross-section as shown in Figures 2G and 2H. In addition or alternatively, the first and second components 52 and 54 may be arranged in a sheath / core configuration, for example, in an eccentric sheath / core configuration illustrated in Figures 2B and 2C. In the eccentric sheath / core bicomponent fiber illustrated in Figure 2B, one component completely encloses or surrounds the other, but is asymmetrically located in the multicomponent fiber, allowing for fiber crimping (e.g., the first component 52 surrounds component 54). The eccentric sheath / core configuration illustrated by Figure 2C includes a first component 52 (e.g., sheath component) that substantially encloses but not completely surrounds the second component 54 (e.g., core component), because some portion of the second component may be exposed and may form part of the outermost surface of the fiber 50. As additional examples, bicomponent fibers may include hollow fibers shown in Figures 2D and 2E, or multi-lobed fibers shown in Figure 2F. However, it should be noted that numerous other cross-sectional configurations and / or fiber shapes may be suitable according to certain embodiments of the present invention.

[0046] In multiple crimped bicomponent fibers, according to certain embodiments of the present invention, each polymer component may exist in a ratio (by volume or mass (my)) from about 85:15 to about 15:85. A ratio of approximately 50:50 (by volume or mass) may be desirable according to certain embodiments of the present invention. However, the specific ratio adopted may vary as desired. For example, at most 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. In addition or alternatively, the first polymer material may constitute about 20 wt.% to about 80 wt.% of a plurality of crimped bicomponent fibers, for example, at least about any of the following: 20, 25, 30, 35, 40, 45, 50, and 55 wt.%, and / or up to about any of the following: 80, 75, 70, 65, 60, and 55 wt.%. In addition or alternatively, the second polymer material may constitute about 20 wt.% to about 80 wt.% of a plurality of crimped bicomponent fibers, for example, at least about any of the following: 20, 25, 30, 35, 40, 45, 50, and 55 wt.%, and / or up to about any of the following: 80, 75, 70, 65, 60, and 55 wt.%.

[0047] In a certain embodiment of the present invention, the first polymer blend, the second polymer blend, or both may contain less than about 10% by weight of a total polypropylene-polyethylene copolymer. For example, at least any of the following: 0, 0.5, 1, 2, 3, 4, and 5% by weight, and / or up to any of the following: 10, 9, 8, 7, 6, and 5% by weight. In this regard, the bicomponent fiber may contain a total polymer component having less than about 10% by weight of a total polypropylene-polyethylene copolymer. For example, at least any of the following: 0, 0.5, 1, 2, 3, 4, and 5% by weight, and / or up to any of the following: 10, 9, 8, 7, 6, and 5% by weight.

[0048] According to certain embodiments of the present invention, the second polymer material may optionally further include a compatible agent containing acid anhydride functionality, such as maleic anhydride or a maleic anhydride-modified polymer. In addition or alternatively, the first polymer material, the second polymer material, or both may further include one or more fillers, such as one or more organic fillers and / or one or more inorganic fillers (e.g., fine 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 include one or more slip agents, such as amides. One or more slip agents may include, for example, primary amides, secondary amides, tertiary amides, bisamides, or any combination thereof. According to certain embodiments of the present invention, one or more slip agents may include one or more primary amides. For example, suitable primary amides as slip agents according to certain embodiments of the present invention may include erucamide, oleamide, strearamide, behenamide, or any combination thereof. Alternatively or in addition, certain embodiments of the present invention may include one or more slip agents comprising one or more secondary amides. For example, suitable secondary amides as slip agents according to certain embodiments of the present invention include oleyl palmitamide, stearyl erucamide, or any combination thereof. Alternatively or in addition, certain embodiments of the present invention may include one or more slip agents comprising one or more bisamides, such as ethylenebisamide. For example, suitable bisamides as slip agents according to certain embodiments of the present invention include ethylenebisstrearamide, ethylenebisoleamide, or any combination thereof. Slip agents according to certain embodiments of the present invention may include amides (e.g., primary amides, secondary amides, tertiary amides, bisamides, etc.) comprising one or more saturated or unsaturated aliphatic chains. According to certain embodiments of the present invention, one or more aliphatic chains may each independently contain about 1 to about 30 carbon atoms (e.g., about 5 to about 30 carbon atoms). For example, secondary amides and bisamides may contain two saturated and / or unsaturated carbon chains, each independently containing about 1 to about 30 carbon atoms (e.g., about 5 to about 30 carbon atoms).For example, one or more aliphatic chains may each independently contain at least one of the following: 1, 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 carbon atoms, and / or up to about 30, 29, 28, 27, 26, 25, 20, and 15 carbon atoms (e.g., about 15 to about 25 carbon atoms, about 20 to about 30 carbon atoms, etc.). According to certain embodiments of the present invention, the slip agent may contain an amide comprising an unsaturated aliphatic chain having one or more unsaturated elements. An unsaturated element corresponds to two fewer hydrogen atoms than in a saturated formula. For example, a single double bond would correspond to one unsaturated element, and a triple bond would correspond to two unsaturated elements. According to certain embodiments of the present 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).

[0049] As noted above, the multiple crimped bicomponent fibers may include circular cross-sections, non-circular cross-sections, or both. For example, non-circular cross-sections may include pie-shaped, multi-lobed, or ribbon-shaped cross-sections. According to certain embodiments of the present invention, the multiple crimped bicomponent fibers include non-circular cross-sections having an aspect ratio of at least about 1.5:1, for example, from about 1.5:1 to about 10:1.

[0050] According to certain embodiments of the present invention, the plurality of crimped bicomponent fibers may include fibers with a circular cross-section ranging from about 0 to about 100 wt.%, for example, at least about any of the following: 0, 5, 10, 20, 30, 40, and 50 wt.%, and / or up to about any of the following: 100, 95, 90, 80, 70, 60, and 50 wt.%. In addition or alternatively, the plurality of crimped bicomponent fibers may include fibers with a non-circular cross-section ranging from about 0 to about 100 wt.%, for example, at least about any of the following: 0, 5, 10, 20, 30, 40, and 50 wt.%, and / or up to about any of the following: 100, 95, 90, 80, 70, 60, and 50 wt.%.

[0051] According to certain embodiments of the present invention, a plurality of crimped bicomponent fibers define a first nonwoven layer, and the nonwoven fabric further includes one or more additional nonwoven layers, for example, comprising at least a second nonwoven layer. In this respect, the nonwoven fabric may include a multilayer nonwoven fabric. The one or more additional layers may include, for example, a spunbond layer, a meltblown layer, a carding layer, a water-entangled layer, a cellulose layer, or any combination thereof. According to certain embodiments of the present invention, the nonwoven fabric includes one or more cellulose layers located directly or indirectly between the first nonwoven layer and the second nonwoven layer, where the second nonwoven layer includes a second spunbond layer or a spunbond-meltblown-spunbond layer.

[0052] According to certain embodiments of the present invention, the nonwoven fabric may have a basis weight of at least about 14 grams per square meter (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 up to about any of the following: 100, 95, 90, 85, 80, 75, 70, 65, and 60 gsm.

[0053] In another embodiment, the present invention provides a method for producing a nonwoven fabric. The method may include: (a) forming a first polymer melt comprising a first polymer or a first polymer blend; (b) forming a second polymer melt comprising a second polymer blend comprising (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibleizer comprising a polypropylene-polyethylene copolymer; (c) forming a plurality of bicomponent fibers by melt spinning the first and second polymer melts through a bicomponent spinneret pack; (d) providing a plurality of crimped bicomponent fibers by allowing the plurality of bicomponent fibers to crimp prior to or during deposition on an aggregate surface, or by subjecting the plurality of bicomponent fibers to a crimping process; and (e) consolidating the plurality of crimped bicomponent fibers to form a nonwoven fabric. Alternatively, the method may include: (a) forming a first polymer melt comprising a first polymer or a first polymer blend; (b) forming a second polymer melt comprising a second polymer blend comprising (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibleizer comprising a polypropylene-polyethylene copolymer; (c) forming a plurality of bicomponent fibers by melt spinning the first and second polymer melts through a bicomponent spinneret pack; (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 process to provide a nonwoven fabric. According to one embodiment of the present invention, the bicomponent spinneret pack comprises an orifice through which the plurality of bicomponent fibers are extruded.

[0054] According to certain embodiments of the present invention, the step of forming a second polymer melt comprises selecting and blending at least one polypropylene polymer, at least one polyethylene polymer, and at least one polypropylene-polyethylene copolymer at an elevated temperature, 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 may be from about 1 to about 35, for example, at least about any of the following: 1, 3, 5, 8, 10, 12, 15, 18, and 20, and / or at most about any of the following: 35, 32, 20, 28, 26, 25, 24, 22, and 20. According to certain embodiments of the present invention, the elevated temperature may range from about 190°C to about 250°C, for example, at least about any of the following: 190, 200, 210, and 215°C, and / or at most about any of the following: 250, 245, 240, 235, 230, 225, 220, and 215°C. According to certain embodiments of the present invention, the first polymer blend and the second polymer blend may be extruded and / or melt-spun at one or more of the elevated temperatures or temperature ranges referenced above. According to certain embodiments of the present invention, the first polymer blend and the second polymer blend may be extruded and melt-spun at the same elevated temperature.

[0055] According to certain embodiments of the present invention, the step of consolidating a plurality of bicomponent fibers or a plurality of crimped bicomponent fibers may include a thermal bonding step, an ultrasonic bonding step, a mechanical bonding step, an adhesive bonding step, or any combination thereof. The consolidation step may include, for example, forming a plurality of individual bonded areas by a thermal bonding step or an ultrasonic step. In this respect, the plurality of individual bonded areas define a bonded area. The bonded area may consist of, for example, about 3% to about 30% of the nonwoven fabric, for example, at least about any of the following: 3, 4, 5, 6, 8, 10, 12, 14, and 15%, and / or at most about any of the following: 30, 28, 26, 25, 24, 22, 20, 18, 16, and 15%. In addition, or alternatively, the step of forming multiple individual joints may be carried out at temperatures ranging from 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.

[0056] In yet another embodiment, the present invention provides a molded article comprising one or more nonwoven fabrics as described and disclosed herein. The molded article may include adult diapers, baby diapers, pull-ups, or feminine hygiene pads. According to certain embodiments of the present invention, the molded article may include a top sheet comprising a nonwoven fabric as described and disclosed herein. [Examples]

[0057] This disclosure is further illustrated by the following examples. These should not be interpreted as limiting. In other words, the specific features described in the following examples are merely illustrative and not limiting.

[0058] Example Set 1 Nine different crimped bicomponent fibers (i.e., samples 1-9) were produced, and their average free-state crimp length was measured. Each bicomponent fiber was a side-by-side bicomponent fiber, where 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 average free-state crimp length was measured for each of the different crimped bicomponent fibers. The results are summarized in Table 1 below.

[0059] Sample 1 was a control sample. All polymer materials consisted of 100% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg). In Sample 2, the first polymer material consisted of 100% by weight 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 100% by weight polypropylene copolymer commercially available as SV956 from LyondellBasell.

[0060] In Sample 3, the first polymer material consisted of 100% by weight 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 a blend of (i) 80% by weight polypropylene homopolymer with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg) (i.e., PP3155E5 from Exxon), (ii) 15% by weight linear low-density polyethylene with an MFR of 2.5 g / 10 min according to ASTM-D1238 (190°C / 2.16 kg) (i.e., PE-Dowlex2036.01G from Dow), and (iii) 5% by weight EP-iPP diblock polymer with an MFR of 9.5 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg) (i.e., Intune®-Dow D5545).

[0061] In Sample 4, the first polymer material consisted of (1) a blend of 97% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (ii) a blend of 3% by weight meltblown polypropylene with an MFR of 500 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg). The second polymer material consisted of a blend of (i) 80% by weight polypropylene homopolymer with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg) (i.e., PP3155E5 from Exxon), (ii) 15% by weight linear low-density polyethylene with an MFR of 2.5 g / 10 min according to ASTM-D1238 (190°C / 2.16 kg) (i.e., PE-Dowlex2036.01G from Dow), and (iii) 5% by weight EP-iPP diblock polymer with an MFR of 9.5 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg) (i.e., Intune®-Dow D5545).

[0062] In Sample 5, the first polymer material consisted of 100% by weight 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 100% by weight polypropylene random copolymer, commercially available as RP448S from LyondellBasell.

[0063] In Sample 6, the first polymer material consisted of 100% by weight 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 100% by weight polypropylene copolymer commercially available from LyondellBasell as Pro-Fax-SDS242.

[0064] In Sample 7, the first polymer material consisted of 100% by weight 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 97% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg) and 3% by weight Dowlex polyethylene.

[0065] In Sample 8, the first polymer material consisted of 100% by weight 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% by weight 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% by weight Dowlex polyethylene, and (iii) 2% by weight 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).

[0066] In Sample 9, the first polymer material consisted of 100% by weight 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) 86.5% by weight 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) 10% by weight Dowlex polyethylene, and (iii) 3.5% by weight 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).

[0067] As shown in Table 1, Sample 3 was able to provide an average free-state crimp length using a blend of polypropylene, polyethylene, and a small amount of compatibleizer. In this respect, the improved average free-state crimp achieved by Sample 3 was achieved using significantly less polypropylene copolymer. Details regarding the specific compositions of the first and second polymer materials of each sample are summarized more concisely in Table 2.

[0068] Example Set 2 Thirteen additional (13) different crimped bicomponent fibers (i.e., samples 10-22) were produced, and their average free-state crimp length was measured. In these samples, each bicomponent fiber was a side-by-side bicomponent fiber, but the weight percentages of the first polymer material and the second polymer material of the bicomponent fiber were varied as shown in Table 2. The average free-state crimp length was measured for each of the different crimped bicomponent fibers. The results are summarized in Table 1 below.

[0069] In Sample 10, the first polymer material consisted of 100% by weight 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 80% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), 15% by weight Dowlex polyethylene (i.e., PE-Dowlex2036.01G from Dow) with an MFR of 2.5 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and 5% by weight 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). The first polymer material constituted 70% by weight of the bicomponent fiber, and the second polymer material constituted 30% by weight of the bicomponent fiber.

[0070] In Sample 11, the first and second polymer materials were identical to those in Sample 10. However, in Sample 11, the first polymer material constituted 50% by weight of the bicomponent fiber, and the second polymer material constituted 50% by weight of the bicomponent fiber.

[0071] In Sample 12, the first and second polymer materials were identical to those in Sample 10. However, in Sample 12, the first polymer material constituted 30% by weight of the bicomponent fiber, and the second polymer material constituted 70% by weight of the bicomponent fiber.

[0072] In Sample 13, the first polymer material consisted of a blend of (i) 97% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (ii) 3% by weight meltblown polypropylene with an MFR of 1800 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg). The second polymer material consisted of a blend of (i) 80% by weight polypropylene homopolymer with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg) (i.e., PP3155E5 from Exxon), (ii) 15% by weight linear low-density polyethylene with an MFR of 2.5 g / 10 min according to ASTM-D1238 (190°C / 2.16 kg) (i.e., PE-Dowlex2036.01G from Dow), and (iii) 5% by weight EP-iPP diblock polymer with an MFR of 9.5 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg) (i.e., Intune®-Dow D5545). The first polymer material constituted 70% by weight of the bicomponent fiber, and the second polymer material constituted 30% by weight of the bicomponent fiber.

[0073] In Sample 14, the first and second polymer materials were identical to those in Sample 13. However, in Sample 14, the first polymer material constituted 50% by weight of the bicomponent fiber, and the second polymer material constituted 50% by weight of the bicomponent fiber.

[0074] In sample 15, the first and second polymer materials were identical to those in sample 13. However, in sample 15, the first polymer material amounted to 30% by weight of the bicomponent fiber, and the second polymer material amounted to 70% by weight of the bicomponent fiber.

[0075] In Sample 16, the first polymer material consisted of 100% by weight 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) 77% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (ii) 15% by weight linear low-density polyethylene (i.e., PE-Dow from Dow) with an MFR of 2.5 g / 10 min according to ASTM-D1238 (190°C / 2.16 kg). (iii) a blend of 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), and (iv) a blend of 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 constituted 70 wt% of the bicomponent fibers, and the second polymer material constituted 30 wt% of the bicomponent fibers.

[0076] In Sample 17, the first and second polymer materials were identical to those in Sample 16. However, in Sample 16, the first polymer material constituted 50% by weight of the bicomponent fiber, and the second polymer material constituted 50% by weight of the bicomponent fiber.

[0077] In Sample 18, the first and second polymer materials were identical to those in Sample 16. However, in Sample 18, the first polymer material constituted 30% by weight of the bicomponent fiber, and the second polymer material constituted 70% by weight of the bicomponent fiber.

[0078] In Sample 19, the first polymer material consisted of a blend of (i) 99% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (ii) 1% by weight meltblown polypropylene with an MFR of 1800 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg). The second polymer material consisted of a blend of (i) 80% by weight 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) 15% by weight Dowlex polyethylene (i.e., PE-Dowlex2036.01G from Dow) with an MFR of 2.5 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (iii) 5% by weight 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). The first polymer material constituted 50% by weight of the bicomponent fiber, and the second polymer material constituted 50% by weight of the bicomponent fiber.

[0079] In Sample 20, the first polymer material consisted of a blend of (i) 98% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (ii) 2% by weight meltblown polypropylene with an MFR of 1800 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg). The second polymer material consisted of a blend of (i) 80% by weight 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) 15% by weight Dowlex polyethylene (i.e., PE-Dowlex2036.01G from Dow) with an MFR of 2.5 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (iii) 5% by weight 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). The first polymer material constituted 50% by weight of the bicomponent fiber, and the second polymer material constituted 50% by weight of the bicomponent fiber.

[0080] In Sample 21, the first polymer material consisted of a blend of (i) 97% by weight polypropylene homopolymer (i.e., PP3155E5 from Exxon) with an MFR of 36 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (ii) 3% by weight meltblown polypropylene with an MFR of 1800 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg). The second polymer material consisted of a blend of (i) 82% by weight 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) 15% by weight Dowlex polyethylene (i.e., PE-Dowlex2036.01G from Dow) with an MFR of 2.5 g / 10 min according to ASTM-D1238 (230°C / 2.16 kg), and (iii) 3% by weight 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). The first polymer material constituted 50% by weight of the bicomponent fiber, and the second polymer material constituted 50% by weight of the bicomponent fiber.

[0081] In Sample 22, the first polymer material consisted of 100% by weight 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 100% by weight 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 polymer material corresponded to 50% by weight of the bicomponent fiber, and the second polymer material corresponded to 50% by weight of the bicomponent fiber.

[0082] [Table 1]

[0083] [Table 2A] [Table 2B]

[0084] These and other modifications and variations of the present invention can be carried out by those skilled in the art without departing from the spirit and scope of the invention as more specifically defined in the appended claims. In addition, it should be understood that the various embodiments may be interchangeable in whole or in part. Furthermore, those skilled in the art will understand that the foregoing descriptions are illustrative only and are not intended to limit the invention as further described in such appended claims. Accordingly, the spirit and scope of the appended claims should not be limited to the exemplary descriptions of the variations contained herein. [Explanation of Symbols]

[0085] A First polymer composition B. Second polymer composition 50 crimped bicomponent fibers 52 First polymer component 54. Second polymer component

Claims

1. A nonwoven fabric comprising a plurality of crimped bicomponent fibers having a first component comprising a first polymer material comprising a first polymer or a first polymer blend and a second component comprising a second polymer material, 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 compatibleizer comprising or consisting of at least one polypropylene-polyethylene copolymer.

2. The nonwoven fabric according to claim 1, wherein the first polymer material comprises polyolefins, for example, one or more polypropylenes, one or more polyethylenes, or any combination thereof.

3. The nonwoven fabric according to claim 1, wherein the first polymer material comprises a first polypropylene having a first melt flow rate (MFR) and a second polypropylene having a second MFR, wherein the second MFR is greater than or equal to the first MFR.

4. 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. The nonwoven fabric according to claim 3, wherein the ratios are 34:1, 32:1, 30:1, 28:1, 26:1, and 25:

1.

5. The nonwoven fabric according to claims 3 to 4, wherein the first polymer material comprises about 70 wt.% to about 99 wt.% of the first polypropylene, for example at least about any of the following: 70, 75, 80, 85, and 90 wt.%, and / or up to any of the following: 99, 98, 97, 96, 95, 94, 93, 92, 91, and 90 wt.%, and the first polymer material comprises about 1 wt.% to about 10 wt.% of the second polypropylene, for example at least about any of the following: 1, 2, 3, 4, and 5 wt.%, and / or up to any of the following: 10, 9, 8, 7, 6, and 5 wt.%.

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

7. The nonwoven fabric according to claim 6, wherein the at least one polypropylene polymer is a first polypropylene polymer having a melt flow rate (MFR) of about 10 to about 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 having an MFR of about 1 to about 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, for example EP-iPP diblock polymer, having an MFR of about 0.5 to about 20 g / 10 min as determined by ASTM-D1238 (230°C / 2.16 kg).

8. The nonwoven fabric according to claim 7, wherein the first polypropylene-polyethylene copolymer has an ethylene monomer content of about 5 to about 60% by weight, for example, at least about any 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% by weight, and / or at most about any of the following: 60, 58, 56, 55, 54, 52, 50, 48, 46, and 45% by weight.

9. The nonwoven fabric according to claims 1 to 8, wherein the plurality of crimped bicomponent fibers include continuous fibers, such as spunbond fibers, staple fibers, or a combination thereof.

10. The nonwoven fabric according to claims 1 to 9, wherein the plurality of crimped bicomponent fibers include a side-by-side configuration, a sheath-core configuration, a pie configuration, a sea-island configuration, a multi-lobed configuration, or any combination thereof.

11. The nonwoven fabric according to claims 1 to 10, wherein the first polymer material constitutes about 20 wt.% to about 80 wt.% of the plurality of crimped bicomponent fibers, for example, at least about any of the following: 20, 25, 30, 35, 40, 45, 50, and 55 wt.%, and / or up to any of the following: 80, 75, 70, 65, 60, and 55 wt.%, and the second polymer material constitutes about 20 wt.% to about 80 wt.% of the plurality of crimped bicomponent fibers, for example, at least about any of the following: 20, 25, 30, 35, 40, 45, 50, and 55 wt.%, and / or up to any of the following: 80, 75, 70, 65, 60, and 55 wt.%.

12. The nonwoven fabric according to claims 1 to 11, wherein the plurality of crimped bicomponent fibers define a first nonwoven fabric layer, and the nonwoven fabric further comprises one or more additional nonwoven fabric layers comprising at least a second nonwoven fabric layer, the one or more additional layers comprising a spunbond layer, a meltblown layer, a carding layer, a water-entangled layer, a cellulose layer, or any combination thereof.

13. The nonwoven fabric according to claim 12, wherein the 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.

14. How to make nonwoven fabric, including the following: (a) Forming a first polymer melt comprising a first polymer or a first polymer blend, (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 compatibleizer comprising a polypropylene-polyethylene copolymer. (c) Forming a plurality of bicomponent fibers by melt spinning the first polymer melt and the second polymer melt through a bicomponent spinneret pack. (d) Allowing the plurality of bicomponent fibers to crimp prior to or during their deposition on the accumulation surface, or subjecting the plurality of bicomponent fibers to a crimping process to provide a plurality of crimped bicomponent fibers, and (e) Consolidating the plurality of crimped bicomponent fibers to form a nonwoven fabric according to any one of claims 1 to 42.

15. How to make nonwoven fabric, including the following: (a) Forming a first polymer melt comprising a first polymer or a first polymer blend, (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 compatibleizer comprising a polypropylene-polyethylene copolymer. (c) Forming a plurality of bicomponent fibers by melt spinning the first polymer melt and the second polymer melt through a bicomponent spinneret pack. (d) Consolidating the plurality of bicomponent fibers to form an intermediate nonwoven fabric, and (e) To provide the nonwoven fabric according to any one of claims 1 to 42 by subjecting the plurality of bicomponent fibers of the intermediate nonwoven fabric to a crimping process.

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