Nonwoven fabric suitable for medical applications

Abstract

A nonwoven fabric includes a first spunbond layer including a first plurality of crimped continuous fibers, a second spunbond layer including a second plurality of crimped continuous fibers, and a third spunbond layer including a third plurality of crimped continuous fibers, wherein the second spunbond layer is directly or indirectly between the first spunbond layer and the third spunbond layer. The nonwoven fabric can have a thickness (e.g., loft) of at least about 0.3 mm and a hydrostatic pressure of at least about 15 mbar. Methods of making the nonwoven fabric and a protective article are also provided.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Patent Application No. 63 / 197,063, filed June 4, 2021, pursuant to 35 USC §119(e), the entire disclosure of which is expressly incorporated herein by reference. Technical Field

[0003] This invention generally relates to nonwoven fabrics that provide ideal barrier properties for a variety of medical applications, while also providing the user with the desired level of bulkiness and / or softness. The invention also provides methods for manufacturing such nonwoven fabrics, and protective articles (e.g., clothing) comprising such nonwoven fabrics. Background Technology

[0004] Cleanroom gowns are typically used to minimize the spread of infectious agents to patients, surgical sites, and equipment by preventing, for example, the dissemination of bacteria-carrying scales from operating room staff. Therefore, cleanroom gowns help prevent surgical site infections after surgery. In summary, cleanroom gowns have been shown to help reduce the risk of infection.

[0005] According to BS EN 13795:2019 Part 2, most cleanroom garments utilize at least one layer of meltblown fiber, such as a spunbond-meltblown-spunbond (SMS) structure, because they provide sufficient barrier properties and tensile strength. However, these structures have not been well accepted by the market due to their plastic feel.

[0006] Reusable cotton fabrics have also been used in the production of cleanroom garments due to their comfort (cotton feel). However, these materials often fail to meet the required barrier properties, such as the ability to block dry microbial penetration according to EN ISO 22612, which is defined as a critical property in EN 13795:2019 Part 2.

[0007] Therefore, there is still a need for a nonwoven fabric that provides a soft and / or cotton-like feel while also offering sufficient barrier properties for a variety of medical applications, such as cleanroom garments. Summary of the Invention

[0008] One or more embodiments of the present invention can solve one or more of the above-mentioned problems. Certain embodiments of the present invention provide a nonwoven fabric comprising a plurality of spunbond layers. According to certain embodiments of the present invention, the nonwoven fabric comprises a first spunbond layer comprising a first plurality of crimped continuous fibers, a second spunbond layer comprising a second plurality of crimped continuous fibers, and a third spunbond layer comprising a third plurality of crimped continuous fibers, wherein the second spunbond layer is located directly or indirectly between the first and third spunbond layers. According to certain embodiments of the present invention, the nonwoven fabric has a thickness (e.g., bulk) of at least about 0.3 mm (at a pressure of 0.2 kPa) and a hydrostatic pressure of at least about 15 mbar, according to EN ISO 811.

[0009] In another aspect, the present invention provides a method for forming a nonwoven fabric, such as those described and disclosed herein. The method may include providing or forming a first spunbond layer comprising a first plurality of crimped continuous fibers, providing or forming a second spunbond layer comprising a second plurality of crimped continuous fibers, and providing or forming a third spunbond layer comprising a third plurality of crimped continuous fibers. The method may further include positioning the second spunbond layer directly or indirectly between the first and third spunbond layers. The method may also include one or more steps of bonding the first, second, and third spunbond layers together to form a nonwoven fabric, wherein the nonwoven fabric has a thickness of at least about 0.3 mm and a hydrostatic pressure of at least about 15 mbar.

[0010] On the other hand, the present invention provides a protective article comprising a nonwoven fabric as described and disclosed herein, wherein the entire protective article or at least a portion thereof is formed of the nonwoven fabric. For example, the protective article includes a drape, garment (e.g., a cleanroom garment), or part of a clothing (e.g., a cleanroom garment). According to certain embodiments of the invention, the nonwoven fabric and / or protective article (e.g., a cleanroom garment) may have a barrier against microbial penetration of less than 100 CFU, such as less than 50 CFU or less than 20 CFU, as per EN ISO 22612. 8 The challenge concentration (CFU / gram talc) and the vibration time (30 minutes) were determined. Attached Figure Description

[0011] 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 may 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:

[0012] Figure 1The illustration shows continuous crimped fibers (e.g., continuous fibers comprising multiple crimped portions) according to certain embodiments of the present invention; and

[0013] Figure 2A-2H Examples of cross-sectional views of some exemplary multicomponent fibers according to certain embodiments of the present invention are shown. Detailed Implementation

[0014] 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 may 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.

[0015] According to certain embodiments, the present invention provides a nonwoven fabric comprising multiple spunbond layers, each of which comprises multiple crimped continuous fibers (e.g., continuous spunbond fibers having multiple crimped portions). According to certain embodiments of the invention, the nonwoven fabric can provide a soft and / or cotton-like feel while also providing sufficient barrier properties for various medical applications, such as cleanroom garments. For example, the thickness (e.g., bulk and / or looseness) of the nonwoven fabric at 0.2 kPa can be at least 0.3 mm, a thickness level per unit basis weight and / or per layer that conventional melt-spun materials cannot achieve. Additionally, the nonwoven fabric according to certain embodiments of the invention can provide improved hydrostatic pressure, which can be greater than 15 mbar, typically unattainable by conventional spunbond materials (e.g., at the same basis weight). According to certain embodiments of the invention, the nonwoven fabric can have a dry-state microbial penetration resistance of less than about 20 CFU (e.g., less than 100 CFU, according to EN 13795:2019 Part 2) (EN ISO 22612). According to certain embodiments of the invention, combinations of various crimped spunbond fibers and their fine denier produce special spunbond materials (e.g., nonwoven fabrics with outstanding bulk and barrier properties), which may be particularly desirable for use in cleanroom garment applications. For example, nonwoven fabrics according to certain embodiments of the invention meet BS EN 13795-2 2019 – Surgical garments and drapes – Cleanroom garments. To meet this standard, nonwoven fabrics typically require at least one meltblown layer (e.g., an SMS structure). According to certain embodiments of the invention, nonwoven fabrics may be free of meltblown fibers and / or submicron fibers.

[0016] 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).

[0017] 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.

[0018] 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 identifiable as in knitted or woven fabrics. According to certain embodiments of the invention, nonwoven 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.

[0019] As used herein, the term "nonwoven fabric" can include a fiber web 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 performed on a nonwoven fiber web of individually laid fibers to mechanically entangle, thermally bond, or otherwise bond at least a portion of the individual fibers together to form a bonded (e.g., cohesive) fiber web of interconnected fibers.

[0020] As used herein, the terms “consolidated” and “consolidated” can include bringing together at least a portion of the fibers of a nonwoven fiber web or multiple nonwoven fiber webs 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, serve to 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 form discrete or localized deformations in the fiber web material. Furthermore, the term “consolidated” can include an 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 just a few examples. According to certain embodiments of the invention, this fiber web may be considered as a “consolidated nonwoven material,” a “nonwoven fabric,” or simply a “fabric.”

[0021] According to certain embodiments of the invention, consolidation can be achieved by applying heat and / or pressure to a fiber web (e.g., a nonwoven fiber web) via one or more embossing rollers or using a flow of hot fluid (e.g., hot air bonding). A non-limiting and exemplary method includes thermal bonding. Thermal bonding can be achieved by passing the fiber web (e.g., a nonwoven fiber web) through a pressure roll gap formed by two rollers, one of which includes an embossing roller that can be heated and has a plurality of raised protrusions on its surface having one or more geometries (e.g., dots, rhombuses, circles, ellipses, dogbone shapes, etc.), which impart or form corresponding discrete thermal bonding sites on the fiber web (e.g., the nonwoven fiber web). This operational step may be referred to, for example, as “calendering” or “embossing,” wherein the nonwoven fiber web is stretched between an embossing roller having an embossed pattern and a second roller (e.g., an anvil roller), the embossing pattern allowing only a portion of the fiber web to be exposed to heat and pressure. The degree or extent of consolidation can be expressed as a percentage of the total surface area of ​​the consolidated or consolidated fiber web, and can be referred to as a “bonded area” or “consolidated area.” In other words, the terms “bonded area” and “consolidated area,” as used interchangeably herein, can include the area per unit area occupied by local portions formed by bonding fibers to the bonded sites, and can be expressed as a percentage of the total unit area of ​​the consolidated nonwoven material. For example, consolidated nonwoven material (e.g., thermally bonded by embossing rollers) can include multiple discrete, spaced-apart bonded sites or points (e.g., peripheral and internal bonded sites or points) formed by bonding only the fibers of the nonwoven fiber web in the local energy input region. Fibers or fiber portions away from the local energy input remain substantially unbonded to adjacent fibers.

[0022] As used herein, the term "continuous fiber" may include filaments having a high length-to-diameter ratio (i.e., length:diameter), for example, exceeding about 500,000:1, exceeding about 750,000:1, or exceeding about 1,000,000:1. According to certain embodiments of the invention, the term "continuous fiber" may include filaments that are substantially loop-shaped in length.

[0023] 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. It should be noted that spunbond materials used in certain composites of the invention can include those described in the literature. Nonwoven materials.

[0024] 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 are microfibers, which may be continuous or discontinuous, and are typically sticky when deposited on the collection surface.

[0025] 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. Short fibers can be monocomponent or multicomponent fibers.

[0026] As used herein, the term "layer" may include a generally identifiable combination of similar material types and / or functions present in the XY plane.

[0027] As used herein, the term "multicomponent fiber" can include fibers formed from at least two different polymeric materials or compositions (e.g., two or more), extruded from separate extruders but woven together to form a single fiber. The term "bicomponent fiber" as used herein can include fibers formed from two different polymeric materials or compositions, extruded from separate extruders but woven 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 skin / core arrangement in which one polymer is surrounded by another, an eccentric skin / core arrangement, a side-by-side arrangement, a disc arrangement, or an "island" arrangement, each of which is a multicomponent fiber, including those known in the field of bicomponent fibers.

[0028] 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.

[0029] As used herein, the term "crimp" or "crimped" includes three-dimensional crimping or bending, such as folded or compressed portions having an "L" configuration, wavy portions having a "Z" configuration, or crimped portions such as helical configurations. According to certain embodiments of the invention, the term "crimp" or "crimped" does not include random two-dimensional ripples or undulations in the fiber, such as those associated with the normal laying of fibers in a melt-spinning process.

[0030] As used herein, the term "high-loft" includes materials having a z-direction thickness typically exceeding about 0.3 mm and a relatively low bulk density. The thickness of "high-loft" nonwoven fabrics 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, or greater than 0.7 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. As used herein, “high bulk” nonwoven fabrics and / or layers may additionally have a relatively low density (e.g., bulk density – weight per unit volume), for example less than about 60 kg / m³, for example up to about any of the following: 70, 60, 55, 50, 45, 40, 35, 30, and 25 kg / m³ and / or at least about any of the following: 10.15, 20, 25, 30, 35, 40, 45, 50, and 55 kg / m³.

[0031] As used in this article, the term "colony forming unit" (CFU) refers to a unit that expresses the number of culturable microorganisms, where culturable number is the number of microorganisms, single cells, or aggregates that are capable of forming colonies on a solid nutrient medium.

[0032] As used herein, the term "cleanroom garment" refers to wearable clothing, such as workwear used in medical applications, designed and proven to minimize contamination of operating room air by skin flakes originating from the skin of the person wearing it. For example, cleanroom garments may include or consist of a jumpsuit, a shirt, or trousers.

[0033] As used herein, the term "scrub suit" refers to workwear used by operating room staff that does not need to meet the requirements of cleanroom garments. The scrub suit is not primarily designed to prevent airborne transmission from staff and can be designed and treated as the manufacturer deems appropriate.

[0034] As used herein, the term “barrier-free microbial penetration” refers to the ability of a material to resist microbial penetration from one side of the material (e.g., a nonwoven fabric) to the other.

[0035] As used in this article, the term "dry penetration" refers to the effect of the combination of air movement and vibratory mechanical action on microbial penetration under dry conditions.

[0036] When this article refers to melt flow rate (MFR), the MFR value is determined according to the standard procedure ASTM D1238 (2.16 kg, 230 °C).

[0037] 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.

[0038] Some embodiments of the present invention provide nonwoven fabrics comprising multiple spunbond layers. According to some embodiments of the present invention, the nonwoven fabric includes a first spunbond layer comprising a first plurality of crimped continuous fibers, a second spunbond layer comprising a second plurality of crimped continuous fibers, and a third spunbond layer comprising a third plurality of crimped continuous fibers, wherein the second spunbond layer is located directly or indirectly between the first and third spunbond layers. According to some embodiments of the present invention, the nonwoven fabric has a thickness (e.g., bulk) of at least about 0.3 mm and a hydrostatic pressure of at least about 15 mbar. For example, Figure 1 A continuous crimped fiber 50 (e.g., a continuous spunbond fiber comprising a plurality of crimped portions) according to certain embodiments of the present invention is shown, wherein the continuous crimped fiber 50 comprises a plurality of three-dimensional crimped or spiral-shaped crimped portions.

[0039] According to certain embodiments of the invention, the first spunbond layer may contain a basis weight of about 10 to about 30 g / m², for example, at least about any of the following: 10, 12, 15, 18, and 20 gsm, and / or at most about any of the following: 30, 28, 25, 22, 20, 18, and 15 gsm. Additionally or alternatively, the second spunbond layer may contain a basis weight of about 10 to about 30 g / m², for example, at least about any of the following: 10, 12, 15, 18, and 20 gsm, and / or at most about any of the following: 30, 28, 25, 22, 20, 18, and 15 gsm. Additionally or alternatively, the third spunbond layer may contain a basis weight of about 10 to about 30 gsm, for example at least about any of the following: 10, 12, 15, 18 and 20 gsm, and / or at most about any of the following: 30, 28, 25, 22, 20, 18 and 15 gsm.

[0040] According to certain embodiments of the invention, the nonwoven fabric may include a basis weight of about 40 to about 100 gsm, such as at least about any of the following: 40, 45, 50, 60 and 70 gsm, and / or at most about any of the following: 100, 90, 80, 70 and 60 gsm.

[0041] According to certain embodiments of the invention, the first plurality of crimped continuous fibers may have an average diameter of about 8 to about 30 micrometers, for example at least about any one of the following: 8, 10, 12, 14, 15, 16, 18, and 20 micrometers, and / or at most about any one of the following: 30, 28, 26, 25, 24, 23, 22, 21, and 20 micrometers (e.g., 12-20 micrometers). Additionally or alternatively, the second plurality of crimped continuous fibers may have an average diameter of about 8 to about 30 micrometers, for example at least about any one of the following: 8, 10, 12, 14, 15, 16, 18, and 20 micrometers, and / or at most about any one of the following: 30, 28, 26, 25, 24, 23, 22, 21, and 20 micrometers (e.g., 12-20 micrometers). Additionally or alternatively, the third plurality of crimped continuous fibers may have an average diameter of about 8 to about 30 micrometers, for example at least about any one of the following: 8, 10, 12, 14, 15, 16, 18, and 20 micrometers, and / or at most about any one of the following: 30, 28, 26, 25, 24, 23, 22, 21, and 20 micrometers (e.g., 12-20 micrometers).

[0042] According to certain embodiments of the invention, the first plurality of crimped continuous fibers may have an average denier of about 0.6 to about 3, for example at least about any of the following: 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8 and 2, and / or at most about any of the following: 3, 2.8, 2.6, 2.5, 2.4, 2.2 and 2 (e.g., 1-2 denier). Additionally or alternatively, the second plurality of crimped continuous fibers may have an average denier of about 0.6 to about 3, for example at least about any of the following: 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8 and 2, and / or at most about any of the following: 3, 2.8, 2.6, 2.5, 2.4, 2.2 and 2 (e.g., 1-2 denier). Additionally or alternatively, the third plurality of crimped continuous fibers may have an average denier of about 0.6 to about 3, for example at least about any one of the following: 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8 and 2, and / or at most about any one of the following: 3, 2.8, 2.6, 2.5, 2.4, 2.2 and 2 (e.g., 1-2 denier).

[0043] According to certain embodiments of the present invention, the first plurality of crimped continuous fibers may comprise a first plurality of monocomponent fibers or a combination of a first plurality of monocomponent fibers and a first plurality of multicomponent fibers. Additionally or alternatively, the second plurality of crimped continuous fibers may comprise a second plurality of monocomponent fibers or a combination of a second plurality of monocomponent fibers and a second plurality of multicomponent fibers. Additionally or alternatively, the third plurality of crimped continuous fibers may comprise a third plurality of monocomponent fibers or a combination of a third plurality of monocomponent fibers and a third plurality of multicomponent fibers. According to certain embodiments of the present invention, the first plurality of crimped continuous fibers, the second plurality of continuous fibers, and the third plurality of crimped continuous fibers may independently comprise about 0 to about 100% of monocomponent fibers, for example, at least about any one of the following: 0, 10, 20, 30, 40, and 50% of monocomponent fibers and / or at most about any one of the following: 100, 90, 80, 70, 60, and 50% of monocomponent fibers. Additionally or alternatively, the first plurality of crimped continuous fibers, the second plurality of continuous fibers, and the third plurality of crimped continuous fibers may independently comprise about 0 to about 100% of multicomponent fibers, for example at least about any one of the following: 0, 10, 20, 30, 40, and 50% of multicomponent fibers, and / or at most about any one of the following: 100, 90, 80, 70, 60, and 50% of multicomponent fibers.

[0044] According to certain embodiments of the invention, the first plurality of single-component fibers, the second plurality of single-component fibers, and the third plurality of single-component fibers independently comprise a polymeric material comprising a synthetic polymer, such as a polyolefin, a polyester, a polyamide, or any combination thereof. For example, the synthetic polymer may comprise a polyolefin, such as polypropylene, a copolymer comprising propylene units, polyethylene, or a copolymer comprising ethylene units. According to certain embodiments of the invention, for example, the polymeric material may comprise about 10 to about 100 wt% of a polyolefin, for example, at least about any one of the following: 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 wt%, and / or at most about any one of the following: 100, 95, 90, 85, 80, 75, 70, 65, and 60 wt%. Additionally or alternatively, the polymeric material may comprise about 10 to about 100 wt% of a polyolefin-containing copolymer, for example at least about any one of the following: 10, 15, 20, 25, 30, 35, 40, 45, and 50 wt%, and / or at most about any one of the following: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, and 50 wt%. According to certain embodiments of the invention, for example, the polymeric composition may comprise a blend of a polyolefin and a polyolefin-containing copolymer.

[0045] According to certain embodiments of the present invention, the first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, and the third plurality of crimped continuous fibers may independently comprise a plurality of multicomponent fibers (e.g., the first plurality of multicomponent fibers, the second plurality of multicomponent fibers, and the third plurality of multicomponent fibers). For example, the first plurality of multicomponent fibers, the second plurality of multicomponent fibers, the third plurality of multicomponent fibers, or any combination thereof may independently comprise at least a first component and a second component. According to certain embodiments of the present invention, for example, the first component may comprise a first polymer material, and the second component may comprise a second polymer material, wherein the first polymer material is different from the second polymer material. The first polymer material may, for example, comprise a first polyolefin composition, and the second polymer material may comprise a second polyolefin composition. The first polyolefin composition may, for example, comprise a first polypropylene, and the second polyolefin composition may, for example, comprise a second polypropylene and / or a second polyethylene.

[0046] According to certain embodiments of the present invention, the first polyolefin composition may comprise a blend of polyolefin fraction A and polyolefin fraction B, wherein polyolefin fraction A accounts for more than 50% by weight of the first polyolefin composition and has a polyolefin fraction A-MFR that is less than the polyolefin fraction B-MFR of polyolefin fraction B. According to certain embodiments of the present invention, the first polyolefin composition may have an MFR ratio between polyolefin fraction B-MFR and polyolefin fraction A-MFR of about 15:1 to about 100:1, for example, at least about any of the following: 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 and 50:1, and / or at most about any of the following: 100:1, 95:1, 90:1, 85:1, 80:1, 75:1, 70:1, 65:1, 60:1, 55:1 and 50:1. Additionally or alternatively, polyolefin fraction B may comprise about 0.5 wt% to about 20 wt% of the first polyolefin composition.

[0047] According to certain embodiments of the present invention, a first plurality of multicomponent fibers, a second plurality of multicomponent fibers, a third plurality of multicomponent fibers, or any combination thereof may independently comprise a plurality of bicomponent fibers. According to certain embodiments of the present invention, bicomponent fibers may comprise a sheath / core configuration, a side-by-side configuration, a disc configuration, an island configuration, a multileaf configuration, or any combination thereof. According to certain embodiments of the present invention, a sheath / core configuration may comprise an eccentric sheath / core configuration (e.g., a bicomponent fiber) comprising a sheath component and a core component not concentrically located within the sheath component. For example, according to certain embodiments of the present invention, the core component may define at least a portion of the outer surface of a bicomponent fiber having an eccentric sheath / core configuration.

[0048] Figure 2A-2H Examples of cross-sectional views of some non-limiting examples of multi-component fibers according to certain embodiments of the present invention are shown. Figure 2A-2H As shown, the multicomponent fiber 50 may include a first polymer component 52 of a first polymer composition A and a second polymer component 54 of a second polymer composition B. The first and second components 52 and 54 may be arranged in substantially different regions within the cross-section of the multicomponent fiber, said regions extending substantially continuously along the length of the multicomponent fiber. The first and second components 52 and 54 may be arranged in a side-by-side manner, as shown in the diagram. 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 may 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 multicomponent fiber shown, one component completely encloses or surrounds another component, but is located asymmetrically within the multicomponent fiber to cause the fiber to curl (e.g., first component 52 surrounds component 54). Figure 2C The eccentric skin / core configuration shown includes a first component 52 (e.g., a skin component) that substantially surrounds a second component 54 (e.g., a core component), but not entirely because a portion of the second component can be exposed and form part of the outermost surface of the fiber 50. As another example, multicomponent 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. In the multi-component fiber, according to certain embodiments of the invention, the polymer components may 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 may 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.

[0049] As described above, a multicomponent fiber may include a first component comprising a first polymer composition and a second component comprising a second polymer composition, wherein the first polymer composition differs from the second polymer composition. For example, the first polymer composition may comprise a first polyolefin composition, and the second polymer composition may comprise a second polyolefin composition. According to certain embodiments of the invention, the first polyolefin composition may comprise a first polypropylene or a blend of polypropylene, and the second polyolefin composition may comprise a second polypropylene and / or a second polyethylene, wherein the first polypropylene or the blend of polypropylene has a melt flow rate, for example, less than 50 g / 10 min. Additionally or alternatively, the first polypropylene or the blend of polypropylene may have a lower crystallinity than the second polypropylene and / or the second polyethylene.

[0050] According to certain embodiments of the invention, a first polymer composition and a second polymer composition may be selected such that the multicomponent fibers form one or more crimps therein without additional heat being applied at stages such as after the relaxation of tensile force in the diffusion section after the stretching unit but before layup, and / or post-processing, such as after fiber layup and web formation. Thus, the polymer compositions may contain polymers that are different from each other because they have different stress or elastic recovery properties, crystallization rates, and / or melt viscosities. According to certain embodiments of the invention, the polymer compositions are selected to self-crimp by means of the melt flow rates of the first and second polymer compositions as described and disclosed herein. According to certain embodiments of the invention, the multicomponent fibers may, for example, be formed or have crimped fiber portions having helical crimps in a single continuous direction. For example, a polymer composition may be substantially continuous on the inside of a helix formed by the crimped nature of the fibers.

[0051] According to certain embodiments of the invention, for example, the first polymer composition of the first component may contain a first MFR of about 10 g / 10 min to less than 150 g / 10 min, for example, up to about any one of the following: 150, 125, 100, 80, 60, 50, 48, 46, 44, 42, 40, 38, 36, 35, 34, 32 and 30 g / 10 min and / or at least about any one of the following: 10, 12, 15, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34 and 35 g / 10 min. According to certain embodiments of the present invention, the second polymer composition of the second component may contain a second MFR of about 20 g / 10 min to about 150 g / 10 min, for example, up to about any one of the following: 150, 125, 100, 80, 60, 50, 48, 46, 44, 42, 40, 38, 36, 35, 34, 32 and 30 g / 10 min and / or at least about any one of the following: 20, 22, 24, 25, 26, 28, 30, 32, 34 and 35 g / 10 min. According to certain embodiments of the present invention, the difference in MFR between the first polymer composition and the second polymer composition may include about 8 g / 10 min to about 100 g / 10 min, for example, up to about any one of the following: 100, 80, 60, 50, 40, 30, 28, 26, 25, 24, 22, 20, 18, 16, 15, 14, 12, 10 and 8 g / 10 min and / or at least about any one of the following: 8, 10, 12, 14, 15 and 20 g / 10 min.

[0052] As described above, the first polyolefin composition may comprise a blend of polyolefin fractions or components (e.g., polypropylene fraction A and different polypropylene fractions or copolymer fractions containing propylene units B, blended to provide a polypropylene-based blend). For example, the first polyolefin composition may comprise a blend of polyolefin fraction A and a copolymer of polyolefin fraction A or a copolymer containing propylene unit portions B, wherein polyolefin fraction A accounts for more than 50% by weight of the first polyolefin composition and has a lower polyolefin fraction A-MFR than polyolefin fraction B-MFR (e.g., a lower MFR relative to polyolefin fraction B). According to certain embodiments of the invention, for example, the first polyolefin composition has an MFR ratio between the polyolefin fraction B-MFR (e.g., the higher MFR material of both) and the polyolefin fraction A-MFR (e.g., the lower MFR material of both) of about 15:1 to about 100:1, for example, at most about any one of the following: 100:1, 90:1, 80:1, 75:1, 70:1, 65:1, 60:1, 55:1, 50:1, 45:1 and 40:1 and / or at least about any one of the following: 15:1, 18:1, 20:1, 22:1, 24:1, 25:1, 26:1, 28:1, 30:1, 32:1, 34:1, 35:1 and 40:1. According to certain embodiments of the invention, polyolefin fraction B (e.g., the higher MFR material of both) comprises about 0.5% by weight to about 20% by weight of the first polyolefin composition, for example, up to about any one of the following: 20, 18, 16, 15, 14, 12, 10, 8, and 6% by weight of the first polyolefin composition and / or at least about any one of the following: 0.5, 0.75, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10% by weight of the first polyolefin composition. For example, certain embodiments of the invention may include multicomponent fibers, wherein the first and second components are formed from the same base polymer material (e.g., the same polypropylene-low MFR polypropylene), the only difference being the addition of a high MFR polymer or a copolymer containing propylene units (e.g., the high MFR polypropylene or copolymer disclosed herein) to the first component, such that the MFR of the first component is greater than the MFR of the second component. In this respect, the high MFR polymer (e.g., the high MFR polypropylene disclosed herein) may comprise polyolefin fraction B, and the base layer having a significantly lower MFR may comprise polyolefin fraction A. According to this embodiment of the invention, for example, the first component may be formed from a blend of polyolefin fraction A and polyolefin fraction B, while the second component may be formed from polyolefin fraction B. According to some embodiments of the invention, the only difference between the first and second components may be the addition of polyolefin fraction B to the first component. According to some other embodiments of the invention, the first component may be formed from a blend of polyolefin fraction A and polyolefin fraction B, while the second component may be formed from polyethylene or polypropylene in "pure" or unmodified form.

[0053] Additionally or alternatively, multi-component fibers according to certain embodiments of the invention may include a mass or volume ratio between the first and second components of about 85:15 to about 15:85 (by volume or mass), such as up to about any one 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 one of the following: 50:50, 45:55, 40:60, 35:65, 30:70, 25:75, 20:80 and 15:85 by volume or mass.

[0054] According to certain embodiments of the invention, multicomponent fibers may include an average free crimp percentage of about 30% to about 300% (e.g., 30%-100%), 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%. According to certain embodiments of the invention, multicomponent fibers may include a plurality of discrete zigzag crimp portions, a plurality of discrete or continuously coiled or helical crimp portions, or combinations thereof. 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 regard, free or unstretched fiber bundles 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., a 2.5N load cell) becomes constant. The free crimp length is determined using the following parameters: (i) recording the approximate free fiber bundle weight in grams (e.g., xxx g ± 0.002 g); (ii) recording the unstretched bundle length in inches; (iii) setting the Inston 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. The method described above for determining the average free crimp percentage may be particularly advantageous when evaluating continuous fibers with helical crimp. For example, 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.

[0055] According to certain embodiments of the invention, the multicomponent fiber 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.

[0056] According to certain embodiments of the invention, the first spunbond layer, the second spunbond layer, the third spunbond layer, or any combination thereof may contain a slip agent. In this respect, the plurality of fibers forming any layer of the nonwoven fabric may include one or more slip agents, which are incorporated into the body of the fibers (e.g., in the melt spun to form the fibers) and / or applied locally to the outer surface of the fibers. For example, the slip agent may be dispersed in at least a portion of the body portion of the first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, the third plurality of crimped continuous fibers, or any combination thereof. Additionally or alternatively, the slip agent may be locally located on at least a portion of the outer surface of the first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, the third plurality of crimped continuous fibers, or any combination thereof.

[0057] According to certain embodiments of the present invention, the slip agent may include amides. For example, the slip agent may include primary amides, secondary amides, tertiary amides, diamides, or any combination thereof. According to certain embodiments of the present invention, the slip agent may include one or more primary amides, including erucamide, oleamide, chain amide, behenamide, or any combination thereof. Additionally or alternatively, the slip agent may contain one or more diamides comprising ethylenediamides.

[0058] According to certain embodiments of the invention, the slip agent comprises one or more amides, wherein the one or more amides comprise unsaturated aliphatic chains, saturated aliphatic chains, or combinations thereof. According to certain embodiments of the invention, the one or more aliphatic chains may each independently comprise about 1 to about 30 carbon atoms (e.g., about 5 to about 30 carbon atoms). For example, secondary amides and diamides may comprise two saturated and / or unsaturated carbon chains, each of which may each independently comprise about 1 to about 30 carbon atoms (e.g., about 5 to about 30 carbon atoms). By way of example only, the one or more aliphatic chains may each independently comprise at least about any one 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, said 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).

[0059] According to certain embodiments of the invention, the lubricant may comprise, for example, a combination of a larger amount of stearamide and a smaller amount of, for example, erucamide. For instance, the combination of a larger amount of stearamide and a smaller amount of erucamide may comprise about 25 to about 40% by weight of erucamide and about 60 to about 75% by weight of stearamide.

[0060] According to certain embodiments of the invention, the first plurality of crimped continuous fibers may contain 0 to about 5 wt% of a slip agent, for example at least about any one of the following: 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8 and 2 wt%, and / or at most about any one of the following: 5, 4.8, 4.5, 4.2, 4, 3.8, 3.5, 3.2, 3, 2.8, 2.5, 2.2 and 2 wt%. Additionally or alternatively, the second plurality of crimped continuous fibers may contain 0 to about 5 wt% of a slip agent, such as at least about any one of the following: 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8 and 2 wt%, and / or at most about any one of the following: 5, 4.8, 4.5, 4.2, 4, 3.8, 3.5, 3.2, 3, 2.8, 2.5, 2.2 and 2 wt%. Additionally or alternatively, the third plurality of crimped continuous fibers may contain 0 to about 5 wt% of a slip agent, such as at least about any one of the following: 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8 and 2 wt%, and / or at most about any one of the following: 5, 4.8, 4.5, 4.2, 4, 3.8, 3.5, 3.2, 3, 2.8, 2.5, 2.2 and 2 wt%.

[0061] According to certain embodiments of the invention, the first spunbond layer, the second spunbond layer, the third spunbond layer, or any combination thereof may contain hydrophilic additives and / or antistatic additives. In this regard, the plurality of fibers forming any layer of the nonwoven fabric may include one or more hydrophilic additives and / or one or more antistatic additives incorporated into the fiber body (e.g., in the melt spun to form the fiber) and / or locally applied to the outer surface of the fiber. For example, the hydrophilic additives and / or antistatic additives may be dispersed in at least a portion of the body portion of the first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, the third plurality of crimped continuous fibers, or any combination thereof. Additionally or alternatively, the hydrophilic additives and / or antistatic additives may be locally located on at least a portion of the outer surface of the first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, the third plurality of crimped continuous fibers, or any combination thereof.

[0062] According to certain embodiments of the invention, the first spunbond layer, the second spunbond layer, the third spunbond layer, or any combination thereof may include an antistatic treatment. For example, some fabrics may require an antistatic treatment to prevent the generation of sparks or dust particles on the fabric surface. According to certain embodiments of the invention, an antistatic additive may be blended and extruded with a polymer (thermally melted) forming a plurality of fibers, said plurality of fibers forming the first spunbond layer, the second spunbond layer, the third spunbond layer, or any combination thereof. The antistatic additive may include a topical surfactant applied to at least one surface of the fabric. The antistatic additive is not necessarily limited, but may include nonionic (polyethylene glycol fatty acid esters, fatty acid diethanolamides), anionic (alcohol sulfate salts), cationic (quaternary ammonium compounds), and amphoteric surfactants.

[0063] According to certain embodiments of the invention, the first spunbond layer may contain about 0 to about 5 wt% of an antistatic additive, for example, at least about any one of the following: 0, 0.1, 0.3, 0.5, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, and 2.6 wt% of an antistatic additive, and / or at most about any one of the following: 5, 4.5, 4, 3.5, 3, and 2.6 wt% of an antistatic additive. Additionally or alternatively, the second spunbond layer may contain about 0 to about 5 wt% of an antistatic additive, for example, at least about any one of the following: 0, 0.1, 0.3, 0.5, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, and 2.6 wt% of an antistatic additive, and / or at most about any one of the following: 5, 4.5, 4, 3.5, 3, and 2.6 wt% of an antistatic additive. Additionally or alternatively, the third spunbond layer may contain about 0 to about 5 wt% of antistatic additives, for example at least about any one of the following: 0, 0.1, 0.3, 0.5, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, and 2.6 wt% of antistatic additives, and / or at most about any one of the following: 5, 4.5, 4, 3.5, 3, and 2.6 wt% of antistatic additives. According to certain embodiments of the invention, the first spunbond layer may include a larger amount of antistatic additives than the third spunbond layer.

[0064] According to certain embodiments of the invention, the nonwoven fabric may be formed entirely of a plurality of spunbond layers, for example, about 2 to about 10 spunbond layers (e.g., 3, 4, 5, 6, 7, 8 and 9 spunbond layers). As described above, for example, the nonwoven fabric may be free of meltblown fibers and / or submicron fibers.

[0065] According to certain embodiments of the invention, the nonwoven fabric may have a longitudinal (MD) tensile strength of about 50 to about 150 N / 5 cm, for example at least about any of the following: 50, 55, 60, 65, 70, 75, 80, 85 and 90 N / 5 cm, and / or at most about any of the following: 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95 and 90 N / 5 cm. Additionally or alternatively, the nonwoven fabric may have a transverse (CD) tensile strength of about 25 to about 85 N / 5 cm, for example at least about any of the following: 25, 30, 32, 35, 38, 40, 42, 45, 48 and 50 N / 5 cm, and / or at most about any of the following: 85, 80, 75, 70, 65, 60, 55 and 50 N / 5 cm.

[0066] According to certain embodiments of the invention, the nonwoven fabric may have an MD elongation of about 20 to about 180%, for example at least about any one of the following: 20, 30, 40, 50, 60, 70, 75, 80, 85 and 90%, and / or at most about any one of the following: 180, 175, 170, 165, 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95 and 90%. Additionally or alternatively, the nonwoven fabric may have a CD elongation of about 20% to about 180%, for example at least about any one of the following: 20, 30, 40, 50, 60, 70, 75, 80, 90, 100, 110 and 115%, and / or at most about any one of the following: 180, 170, 160, 150, 140, 130, 125, 120 and 115%.

[0067] According to certain embodiments of the invention, the nonwoven fabric may have a thickness in the z direction perpendicular to the CD and MD of the nonwoven fabric, wherein the thickness may be from about 0.3 to about 3 mm at 0.2 kPa, for example at least about any of the following: 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 mm at 0.2 kPa, and / or at most about 3, 2.8, 2.6, 2.5, 2.2, 2, 1.8, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1, 0.9 and 0.8 mm at 0.2 kPa (e.g. 0.3 to 1.5 mm at 0.2 kPa). Additionally or alternatively, the nonwoven fabric may have a breathability of about 40 to about 600 cfm, for example, at least about any of the following: 40, 60, 80, 100, 120, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 and 250 and / or at most about 600, 570, 540, 510, 480, 450, 420, 400, 390, 380, 360, 350, 330, 320, 300, 290, 280, 270, 260 and 250 cfm. Additionally or alternatively, the nonwoven fabric may have a hydrostatic pressure of about 15 bar to about 30 mbar as determined according to AATCC 127, for example at least about any of the following: 15, 16, 18, 20, 22 and 25 mbar, and / or at most about any of the following: 30, 28, 26, 25 mbar. Additionally or alternatively, the nonwoven fabric may have a hydrostatic pressure to basis weight ratio of about 0.3 to about 0.7 (mbar / gsm), for example at least about any of the following: 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48 and 0.5 (mbar / gsm), and / or at most about any of the following: 0.7, 0.68, 0.66, 0.64, 0.62, 0.6, 0.58, 0.56, 0.54, 0.52 and 0.5 (mbar / gsm), wherein the hydrostatic pressure is determined according to AATCC 127.

[0068] According to certain embodiments of the present invention, the average compression stiffness (CAR) of the nonwoven fabric can be from about 300 to about 650 gf / cm². 2 (gf / cm) / mm, for example, at least approximately any of the following: 300, 320, 350, 380, 400, 420, 440, 460, 480, 500, 520 and 540 (gf / cm) 2 ) / mm, and / or at most about any one of the following: 650, 640, 620, 600, 580, 560, and 540 (gf / cm) 2) / mm. Additionally or alternatively, nonwoven fabrics may have approximately 500 to approximately 1200 (gf / cm²). 2 The recovered mean stiffness (RAR) is approximately 500, 520, 550, 580, 600, 620, 650, 680, 700, 720, 740, 760, 780, 800, 820, 840, 860, 880 and 900 (gf / cm²). 2 ) / mm, and / or at most about any one of the following: 1200, 1150, 1100, 1050, 1000, 950, and 900 (gf / cm) 2 ) / mm. Additionally or alternatively, nonwoven fabrics may have a first CAR (gf / cm²) of about 55 to about 90. 2 ) / mm and RAR(gf / cm) 2 The ratio of ) / mm, for example, about 55, 58, 60, 62, 64, 65, 68 and 70, and / or at most about any one of the following: 90, 88, 85, 82, 80, 78, 75, 72 and 70.

[0069] According to certain embodiments of the invention, the nonwoven fabric has a bending average stiffness (BARCD) in the CD direction of about 10 to about 50 gf*mm / rad, for example at least about any of the following: 10, 12, 15, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36 and 38 gf*mm / rad, and / or at most about any of the following: 50, 48, 46, 45, 44, 42, 40 and 38 gf*mm / rad. Additionally or alternatively, the nonwoven fabric may have a bending average stiffness (BARMD) of about 30 to about 110 gf*mm / rad, for example, at least about any one of the following: 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 and 85 gf*mm / rad, and / or at most about any one of the following: 110, 105, 100, 95, 90 and 85 gf*mm / rad. Additionally or alternatively, the nonwoven fabric may have a bending average stiffness factor per basis weight (BRAF) of about 0.8 gf*mm / rad / gsm to about 1.5 gf*mm / rad / gsm as determined by formula (1):

[0070] Equation (1): [(BARCD+BARMD) / 2] / BW,

[0071] BARCD and BARMD are defined as above, and BW is the basis weight of the nonwoven fabric. According to certain embodiments of the invention, for example, BRAF can be from about 0.8 to about 1.5 gf*mm / rad / gsm, for example, at least about any of the following: 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, and 1.3 gf*mm / rad / gsm, and / or at most about any of the following: 1.5, 1.45, 1.4, 1.35, and 1.3 gf*mm / rad / gsm.

[0072] According to certain embodiments of the invention, the nonwoven fabric may optionally include one or more layers of short fibers and / or cellulose fibers (e.g., rayon, pulp, cotton, etc.). According to certain embodiments of the invention, the nonwoven fabric may be free of short fibers, cellulose fibers, or both.

[0073] In another aspect, the present invention provides a method for forming a nonwoven fabric, such as those described and disclosed herein. The method may include providing or forming a first spunbond layer comprising a first plurality of crimped continuous fibers, providing or forming a second spunbond layer comprising a second plurality of crimped continuous fibers, and providing or forming a third spunbond layer comprising a third plurality of crimped continuous fibers. The method may further include positioning the second spunbond layer directly or indirectly between the first and third spunbond layers. The method may also include one or more steps of bonding or consolidating the first, second, and third spunbond layers together to form a nonwoven fabric, wherein the nonwoven fabric has a thickness of at least about 0.3 mm and a hydrostatic pressure of at least about 15 mbar.

[0074] One or more steps of bonding or consolidating the first, second, and third spunbond layers together to form a nonwoven fabric may include one or more consolidation methods, such as those described herein. For example, bonding or consolidation methods for forming a nonwoven fabric may include thermal bonding methods, mechanical bonding methods, chemical bonding methods, air bonding methods, or any combination thereof. According to certain embodiments of the invention, the bonding or consolidation step may include a thermal bonding process, which includes ultrasonic bonding operations and / or hot calendering operations. For example, the thermal bonding process may define a bonding pattern comprising a plurality of individual and separate bonding sites. In this respect, the plurality of individual and separate bonding sites may define a bonding area. According to certain embodiments of the invention, the bonding area may comprise from about 1 to about 30%, for example at least about any one of the following: 1.2, 3, 5, 8, 10, 12, 15, 18, and 20%, and / or at most about any one of the following: 30, 28, 25, 22, and 20%.

[0075] According to certain embodiments of the present invention, the method may include treating a first spunbond layer, a second spunbond layer, a third spunbond layer, or any combination thereof with one or more slip agents and / or one or more antistatic additives as disclosed above. For example, the method may include forming a first polymer melt comprising a first antistatic additive and / or a first slip agent, and melt-spinning a first plurality of crimped continuous fibers, wherein the first plurality of crimped continuous fibers may be self-crimping or crimpable by a post-deposition crimping operation (e.g., thermally induced crimping and / or mechanically formed crimping). Additionally or alternatively, the method may include forming a second polymer melt comprising a second antistatic additive and / or a second slip agent, and melt-spinning a second plurality of crimped continuous fibers, wherein the second plurality of crimped continuous fibers may be self-crimping or crimpable by a post-deposition crimping operation. Additionally or alternatively, the method may include forming a third polymer melt comprising a third antistatic additive and / or a third slip agent, and melt-spinning a third plurality of crimped continuous fibers, wherein the third plurality of crimped continuous fibers may be self-crimping or crimpable by post-deposition crimping operations (e.g., thermally induced crimping and / or mechanically formed crimping).

[0076] According to certain embodiments of the present invention, the step of treating a first spunbond layer, a second spunbond layer, a third spunbond layer, or any combination thereof with one or more antistatic additives and / or one or more slip agents may include locally applying one or more antistatic additives and / or one or more slip agents to the outer surface of the fibers being treated. For example, the method may include locally applying antistatic additives and / or slip agents to a first spunbond layer, a second spunbond layer, a third spunbond layer, or any combination thereof.

[0077] According to certain embodiments of the invention, the method may include subjecting a first spunbond layer, a second spunbond layer, a third spunbond layer, or any combination thereof to a post-layout crimping operation (e.g., a mechanical and / or thermal crimping operation to impart multiple crimped portions to the fiber being processed).

[0078] According to certain embodiments of the invention, the method may include depositing a first spunbond nonwoven fiber web (e.g., a first spunbond layer) onto a support belt, depositing a second spunbond nonwoven fiber web (e.g., a second spunbond layer) directly on top of the first nonwoven fiber web, and depositing a third spunbond nonwoven fiber web (e.g., a third spunbond layer) directly on top of the second nonwoven fiber web to form a multilayer precursor nonwoven fiber web. The multilayer precursor nonwoven fiber web may then be subjected to one or more consolidation operations, such as those described and disclosed herein, to form a nonwoven fabric. As described above, the numerous fibers forming each spunbond layer may comprise naturally crimped continuous fibers and / or crimpable fibers, which may be given one or more crimps before and / or after consolidation. Alternatively, each spunbond layer may be pre-formed as a pre-consolidated individual spunbond fabric. These spunbond layers may be stacked on top of each other and consolidated together to form a nonwoven fabric.

[0079] In another aspect, the present invention provides a protective article comprising a nonwoven fabric as described and disclosed herein, wherein the entire protective article or at least a portion thereof is formed of the nonwoven fabric. For example, the protective article includes a drape (e.g., a surgical drape), garment (e.g., a cleanroom gown or surgical gown), or a portion thereof (e.g., a cleanroom gown). According to certain embodiments of the invention, the nonwoven fabric and / or protective article (e.g., a cleanroom gown) may have a barrier against microbial penetration of less than 100 CFU, for example less than 50 CFU or less than 20 CFU, as determined by EN ISO 22612 using a challenge concentration of 10⁸ CFU / g talc and a vibration time of 30 minutes. Additionally or alternatively, the nonwoven fabric and / or protective article may have a barrier concentration of less than 100 CFU / 100 cm². 2 The cleanliness of the microbial contaminants, as determined by EN ISO 11737-1.

[0080] Example

[0081] 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.

[0082] According to certain embodiments of the invention, a nonwoven fabric consisting of three spunbond layers is prepared. The total basis weight of the nonwoven fabric is 45 gsm. Specifically, each spunbond layer comprising a plurality of continuous spunbond fibers has a plurality of crimped portions therein (e.g., crimped continuous fibers). All fibers in each layer are formed from a single polymer system. In this respect, the polymer composition of the fibers in each spunbond layer is the same. The polymer composition used comprises about 61 wt% polypropylene, about 36 wt% polyolefin-based random copolymer, about 2 wt% coloring pigment, and about 1 wt% slip additive (i.e., erucamide). This nonwoven fabric is particularly bulky and can be described as a highly bulky nonwoven fabric.

[0083] The resistance to microbial penetration of the aforementioned nonwoven fabric samples was tested according to ISO 22612 (2005) and EN 13795-2 (2019). Twelve test samples, each 20 cm × 20 cm in size, were obtained (i.e., two tests of five samples each, plus one sample as a control). The test samples were conditioned at 20°C and 65% relative humidity for 24 hours. The test samples were then steam-sterilized at 121°C for 15 minutes. The first side of the test sample was brought into contact with talc containing Bacillus subtilis spores ATCC 9372 (preserved at ATCC as Bacillus subtilis var. niger). The talc count was 10⁸ CFU / g. The vibration frequency was 20,800 vibrations per minute for 30 minutes. The test results are provided in Tables 1A and 1B below.

[0084] Table 1A

[0085] Test 1 Test 2 CFU / plate CFU / plate Comparison 0 0 Test sample #1 34 24 Test sample #2 37 24 Test sample #3 14 36 Test sample #4 20 23 Test sample #5 17 47

[0086] Table 1B

[0087] <![CDATA[Median (M d )]]> 24 Upper quartiles 36

[0088] A second nonwoven fabric was manufactured in the same manner as the aforementioned nonwoven fabric, except that the total basis weight of the nonwoven fabric was 50 gsm. Various tests were performed on this nonwoven fabric to evaluate several physical properties. A comparative nonwoven fabric was also tested to provide a side-by-side comparison. The comparative nonwoven fabric was a commercially available spunbond fabric with a basis weight of 49 gsm. In this respect, the comparative nonwoven fabric was a monospunbond fabric produced by blending polypropylene resin, a polyolefin-based random copolymer resin, and a slip-enhancing additive to provide softness. Tables 2 and 3 provided below summarize several physical properties analyzed for both the comparative nonwoven fabric and the nonwoven fabric formed according to certain embodiments of the invention (e.g., the nonwoven fabric of the present invention).

[0089] Table 2

[0090]

[0091]

[0092] Table 3

[0093]

[0094]

[0095] The test methods used in Table 2 are as follows: Basis weight was determined according to ASTM D 3776; all strength and elongation properties were determined according to ASTM D5035; air permeability was determined according to ASTM D737; HOM was determined according to WSP 90.3; hydrostatic pressure (HSH) was determined according to AATCC 127; and electrostatic decay was determined according to WSP 40.2. All tests in Table 3 are from FTT (SDL ATLAS Fabric Touch Tester).

[0096] 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 nonwoven fabric, comprising: (i) A first spunbond layer comprising a first plurality of crimped continuous fibers; (ii) A second spunbond layer comprising a second plurality of crimped continuous fibers; as well as (iii) A third spunbond layer comprising a third plurality of crimped continuous fibers, wherein the second spunbond layer is located directly between the first spunbond layer and the third spunbond layer; The nonwoven fabric has a thickness of at least 0.3 mm at 0.2 kPa and a hydrostatic pressure of at least 15 mbar.

2. The nonwoven fabric according to claim 1, wherein, The nonwoven fabric has a thickness ranging from 0.3 mm to 3 mm at 0.2 kPa.

3. The nonwoven fabric according to claim 1, wherein, The nonwoven fabric has a hydrostatic pressure of at least 18 mbar.

4. The nonwoven fabric according to any one of claims 1-3, wherein, The first spunbond layer, the second spunbond layer and the third spunbond layer each have a basis weight of 10 to 30 g / m².

5. The nonwoven fabric according to claim 4, wherein, The first spunbond layer, the second spunbond layer and the third spunbond layer each have a basis weight of 12 to 30 g / m².

6. The nonwoven fabric according to claim 4, wherein, The first spunbond layer, the second spunbond layer and the third spunbond layer each have a basis weight of 15 to 30 g / m².

7. The nonwoven fabric according to any one of claims 1-3, wherein, The first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, and the third plurality of crimped continuous fibers each have an average diameter of 8 to 30 micrometers independently of each other.

8. The nonwoven fabric according to claim 7, wherein, The first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, and the third plurality of crimped continuous fibers each have an average diameter of 12 to 30 micrometers, which are independent of each other.

9. The nonwoven fabric according to claim 7, wherein, The first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, and the third plurality of crimped continuous fibers each have an average diameter of 15 to 30 micrometers, which are independent of each other.

10. The nonwoven fabric according to any one of claims 1-3, wherein, The first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, and the third plurality of crimped continuous fibers each have an average denier of 0.6 to 3 independently.

11. The nonwoven fabric according to claim 10, wherein, The first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, and the third plurality of crimped continuous fibers have an average denier of 1 to 3 independently of each other.

12. The nonwoven fabric according to claim 10, wherein, The first plurality of crimped continuous fibers, the second plurality of crimped continuous fibers, and the third plurality of crimped continuous fibers each have an average denier of 1 to 2 independently of each other.

13. The nonwoven fabric according to any one of claims 1-3, wherein, The first plurality of crimped continuous fibers comprise a first plurality of monocomponent fibers, the second plurality of crimped continuous fibers comprise a second plurality of monocomponent fibers, and the third plurality of crimped continuous fibers comprise a third plurality of monocomponent fibers.

14. The nonwoven fabric according to claim 13, wherein, The first plurality of single-component fibers, the second plurality of single-component fibers, and the third plurality of single-component fibers independently comprise corresponding polymer materials, the corresponding polymer materials comprising corresponding blends of polyolefins.

15. The nonwoven fabric according to claim 14, wherein, The corresponding polymeric materials comprise corresponding blends of copolymers containing polyolefins, wherein the copolymers containing polyolefins are copolymers containing propylene units and / or ethylene units.

16. The nonwoven fabric according to claim 14 or 15, wherein, The respective polymer materials each contain 40 to 100 wt% polyolefin.

17. The nonwoven fabric according to claim 16, wherein, The respective polymer materials each contain 50 to 100 wt% polyolefin.

18. The nonwoven fabric according to claim 16, wherein, The respective polymer materials each contain 60 to 100 wt% polyolefin.

19. The nonwoven fabric according to claim 15, wherein, The respective polymer materials each contain 10 to 100 wt% of a polyolefin-containing copolymer.

20. The nonwoven fabric according to claim 19, wherein, Each of the respective polymer materials contains 20 to 90 wt% of a polyolefin-containing copolymer.

21. The nonwoven fabric according to claim 20, wherein, Each of the respective polymer materials contains 30 to 60 wt% of a polyolefin-containing copolymer.

22. The nonwoven fabric according to any one of claims 1-3, wherein, The first spunbond layer, the second spunbond layer, the third spunbond layer, or any combination thereof contain a slip agent, wherein the slip agent contains an amide.

23. The nonwoven fabric according to claim 22, wherein, The slip agent comprises one or more primary amides, including erucamide, oleamide, streptomycinamide, behenamide, or any combination thereof.

24. The nonwoven fabric according to any one of claims 1-3, wherein, The nonwoven fabric does not contain meltblown fibers, submicron fibers, or both.

25. The nonwoven fabric according to any one of claims 1-3, wherein, The nonwoven fabric has a strength of 300 to 650 gf / cm³. 2 The average compressive stiffness (CAR) is 500 to 1200 gf / cm². 2 The recovered average stiffness (RAR) is 0.5 mm.

26. The nonwoven fabric according to claim 25, wherein, The nonwoven fabric has a strength of 300 to 600 gf / cm³. 2 The average compressive stiffness (CAR) is 0.5 mm.

27. The nonwoven fabric according to claim 25, wherein, The nonwoven fabric has a strength of 400 to 560 gf / cm³. 2 The average compressive stiffness (CAR) is 0.5 mm.

28. The nonwoven fabric according to claim 25, wherein, The nonwoven fabric has a strength of 500 to 1100 gf / cm³. 2 The recovered average stiffness (RAR) is 0.5 mm.

29. The nonwoven fabric according to claim 25, wherein, The nonwoven fabric has a strength of 600 to 900 gf / cm³. 2 The recovered average stiffness (RAR) is 0.5 mm.

30. The nonwoven fabric according to claim 25, wherein, The nonwoven fabric has a compressive average stiffness (gf / cm²) of 0.55 to 0.

90. 2 () / mm and restored mean stiffness (gf / cm) 2 The ratio of ) / mm.

31. The nonwoven fabric according to claim 25, wherein, The nonwoven fabric has a compressive average stiffness (gf / cm²) of 0.55 to 0.

80. 2 () / mm and restored mean stiffness (gf / cm) 2 The ratio of ) / mm.

32. The nonwoven fabric according to claim 30, wherein, The nonwoven fabric has a compressive average stiffness (gf / cm) of 0.60 to 0.

80. 2 () / mm and restored mean stiffness (gf / cm) 2 The ratio of ) / mm.

33. The nonwoven fabric according to any one of claims 1-3, wherein, The nonwoven fabric has a bending average stiffness (BARCD) of 10 to 50 gf*mm / rad on CD and a bending average stiffness (BARMD) of 30 to 110 gf*mm / rad on MD.

34. The nonwoven fabric according to claim 33, wherein, The nonwoven fabric has a bending average stiffness (BARCD) on CD of 20 to 50 gf*mm / rad.

35. The nonwoven fabric according to claim 33, wherein, The nonwoven fabric has a bending average stiffness (BARCD) on CD of 30 to 50 gf*mm / rad.

36. The nonwoven fabric according to claim 33, wherein, The nonwoven fabric has a bending average stiffness (BARMD) on the MD of 30 to 100 gf*mm / rad.

37. The nonwoven fabric according to claim 33, wherein, The nonwoven fabric has a bending average stiffness (BARMD) on the MD of 40 to 90 gf*mm / rad.

38. The nonwoven fabric according to claim 33, wherein, The nonwoven fabric has a bending average stiffness factor (BRAF) of 0.8 to 1.5 gf*mm / rad / gsm, wherein the BRAF is determined by equation (1): Equation (1): [(BARCD+BARMD) / 2] / BW, Wherein BW is the basis weight of the nonwoven fabric.

39. The nonwoven fabric according to claim 38, wherein, The nonwoven fabric has a bending average stiffness factor (BRAF) of 1 to 1.4 gf*mm / rad / gsm.

40. The nonwoven fabric according to claim 38, wherein, The nonwoven fabric has a bending average stiffness factor (BRAF) of 1 to 1.3 gf*mm / rad / gsm.

41. A method for forming a nonwoven fabric, comprising: (i) Providing or forming a first spunbond layer comprising a first plurality of crimped continuous fibers; (ii) Providing or forming a second spunbond layer comprising a second plurality of crimped continuous fibers; (iii) Providing or forming a third spunbond layer comprising a third plurality of crimped continuous fibers; as well as (iv) The first spunbond layer, the second spunbond layer and the third spunbond layer are bonded together to form a nonwoven fabric according to any one of claims 1-40.

42. A protective article comprising a tarpaulin or garment comprising a nonwoven fabric according to any one of claims 1-40.

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