Nonwoven fabrics including recycled polyester

Abstract

Nonwoven fabrics are provided that include (i) a plurality of continuous matrix fibers comprising a first polymeric material having a first melting point and including a first polymer component, in which the first polymer component comprises a first recycled-polyester, and (ii) a plurality of binder fibers having an irregular cross-section randomly dispersed throughout the plurality of matrix fibers, in which the plurality of binder fibers comprising a second polymeric material having a second melting point including a second polymer component. The second melting point being less than the first melting point.

Description

[Technical Field]

[0001] The embodiments of the currently disclosed invention generally relate to nonwoven fabrics comprising a plurality of continuous matrix fibers and a plurality of adhesive fibers, the continuous matrix fibers comprising a first recycled polyester, and the adhesive fibers randomly dispersed within the plurality of matrix fibers and having an irregular cross-section. In this regard, the nonwoven fabric may be provided, for example, in the form of a drying sheet or filter media for air or liquid filtration applications, or as a component.

[0002] A nonwoven fabric is provided, comprising: (i) a plurality of continuous matrix fibers, the continuous matrix fibers comprising a first polymeric material having a first melting point and comprising a first polymeric component, wherein the first polymeric component comprises a first recycled polyester; and (ii) a plurality of adhesive fibers randomly dispersed in the plurality of matrix fibers and having an irregular cross-section, wherein the plurality of adhesive fibers comprises a second polymeric material having a second melting point, the second polymeric material comprising a second polymeric component. The second melting point is lower than the first melting point. [Previous Technology]

[0003] There is growing interest in using recycled plastics in a variety of disposable products. Plastic recycling typically involves recovering waste or scrap plastics and reprocessing the material into usable products. Since most plastics are non-biodegradable, recycling is part of a global effort to reduce plastic waste, which is either incinerated, landfilled, or finds its way into one of the world's oceans. In some cases, the use of recycled plastics may be associated with products exhibiting reduced physical properties compared to products made entirely from virgin plastics, which is undesirable.

[0004] There remains a need in the art for nonwoven fabrics suitable for a variety of applications, including a large number of fibers formed from recycled plastics. [Summary of the Invention]

[0005] One or more embodiments of the present invention can solve one or more of the above-described problems. According to certain embodiments of the present invention, a nonwoven fabric is provided comprising a plurality of continuous matrix fibers having a first melting point and comprising a first polymeric material, the first polymeric material comprising a first polymer component, wherein the first polymeric component comprises a first recycled polyester, such as first recycled polyester terephthalate (rPET). The nonwoven fabric may also comprise a plurality of adhesive fibers randomly dispersed among the plurality of matrix fibers and having an irregular cross-section, wherein the plurality of adhesive fibers comprise a second polymeric material containing a second polymeric component. The second polymeric material has a second melting point lower than the first melting point.

[0006] In another embodiment, the present invention provides a method for manufacturing a nonwoven fabric, comprising the following steps: (a) forming a first polymeric melt having a first melting point and comprising a first polymeric material comprising a first polymer component, wherein the first polymer component comprises a first recycled polyester, such as first recycled polyester terephthalate (rPET); (b) generating a second polymeric melt comprising a second polymeric material comprising a second polymer component, wherein the second polymeric material has a second melting point below the first melting point; (c) melt-spinning the first polymeric melt through a first plurality of spinnerets of a spinning nozzle to form a plurality of continuous matrix fibers comprising the first polymeric material, and melt-spinning the second polymeric melt through a second plurality of spinnerets of a spinning nozzle to form a plurality of bonded fibers comprising the second polymeric material; (d) depositing the plurality of continuous matrix fibers and the plurality of bonded fibers onto a moving strip, wherein the plurality of bonded fibers are randomly dispersed within the plurality of continuous matrix fibers to provide a nonwoven fiber web; and (e) consolidating the nonwoven fiber web to form a nonwoven fabric, such as those described and disclosed herein.

[0007] In another embodiment, the present invention provides a drying sheet comprising a nonwoven substrate containing a nonwoven fabric as disclosed and described herein, and a fabric conditioning agent disposed on the nonwoven substrate.

[0008] In another embodiment, the present invention provides a filter comprising a filter medium comprising the nonwoven fabric described and disclosed herein, wherein the nonwoven fabric is contained within a frame.

Implementation Method

[0010] The invention will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, embodiments of the invention. In fact, the invention 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 so that this disclosure will satisfy applicable legal requirements. As used in the specification and the appended claims, the singular forms "a(a)", "an", and "the" include plural designations unless the context clearly specifies otherwise.

[0011] The term “substantial” or “substantial” may include the full amount specified in some embodiments of the invention, or a majority but not the full amount specified in other embodiments of the invention (e.g., 95%, 96%, 97%, 98%, or 99% of the specified total amount).

[0012] The terms "polymer" or "polymeric" as used interchangeably herein may include, for example, homopolymers, copolymers (e.g., block, graft, random, and alternating copolymers), ternary polymers, and blends and modifiers thereof. Furthermore, unless otherwise specifically limited, the terms "polymer" or "polymeric" shall include all possible structural isomers; stereoisomers, including but not limited to geometric, optical, or mirror-image isomers; and / or any chiral molecular configuration of such polymers or polymeric materials. These configurations include, but are not limited to, homo-, anti-, and hetero-alloy configurations of such polymers or polymeric materials. The terms "polymer" or "polymeric" shall also include polymers derived from various catalyst systems, including but not limited to Ziegler-Natah catalyst systems and metallocene / monosite catalyst systems. According to certain embodiments of the invention, the terms "polymer" or "polymeric" shall also include polymers produced by fermentation processes or of biological origin.

[0013] As used herein, the term "pre-consumer waste" may include plastics (e.g., polyester) that have been recycled from the consumer supply chain (e.g., from beverage bottles that have expired or never been consumed). Plastics (e.g., polyester) may be recycled and then milled and processed into polyester staple fiber raw materials (e.g., recycled polyester fibers).

[0014] As used herein, the term "post-consumer waste" may include plastics (e.g., polyester) that have been recycled from the consumer supply chain (e.g., from beverage bottles, which are then milled and processed into polyester staple fiber raw materials (e.g., recycled polyester fibers)). For example, plastics (e.g., polyester) may include polymeric materials derived from post-consumer sources (e.g., products) such as household, distribution, retail, industrial, and demolition sources, which are disposed of or recycled after completing their intended use as consumer goods (including, for example, plastic containers (e.g., bottles) and plastic bags).

[0015] As used herein, the term "post-industrial waste" may include plastics (e.g., polyester) generated during the manufacturing process of upstream polyester and plastic products. Non-limiting examples of such manufacturing processes may originate from virgin fiber producers, tire cord manufacturers, polymerization plants, and other plastic products.

[0016] As used herein, the term "recycled polyester fiber" can include man-made fibers derived from pre-consumer polyester waste, post-consumer polyester waste, and / or post-industrial polyester waste. In this respect, instead of using new resins (e.g., virgin resins) to form fibers (e.g., petroleum), recycled polyester fibers are generated from existing plastics (e.g., discarded water bottles). Compared to virgin polyester, the use of recycled polyester reduces its environmental impact. For example, recycled polyester reduces dependence on virgin petroleum as a feedstock and diverts used plastics from landfills.

[0017] As used herein, the terms "nonwoven" and "nonwoven web" can include a web having a structure of individual fibers, filaments, and / or threads that are interwoven with each other but not in a recognizable repeating manner as in knitted or woven fabrics. According to certain embodiments of the invention, nonwoven fabrics or webs can be formed by, for example, any process generally known in the art (e.g., meltblowing, spunbonding, needle punching, hydroentanglement, air-laid web formation, and bonded carding processes). As used herein, "nonwoven web" can include multiple individual fibers that have not yet undergone a consolidation process.

[0018] As used herein, the terms "fabric" and "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 nonwoven fiber web of individually laid fibers can be bonded or consolidated to bond at least a portion of the individual fibers together to form a coherent (e.g., cohesive) fiber web of interconnected fibers.

[0019] As used herein, the terms "consolidated" and "consolidated" can include bringing together at least a portion of the fibers of a nonwoven fiber web closer together or subsequently therebetween (e.g., thermally fused together, chemically bonded together, bonded by air, and / or mechanically entangled together) to form one or more bonded points, which, compared to an unconsolidated fiber web, have the effect of increasing resistance to external forces (e.g., abrasion and tensile forces). A bonded site or multiple bonded sites may, for example, 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 the entire nonwoven fiber web that has been treated, for example, by thermal bonding, bonded by air, or mechanical entanglement (e.g., hydraulic entanglement) (to name just a few examples), such that at least a portion of the fibers are brought closer together or subsequently therebetween (e.g., thermally fused together, chemically bonded together, bonded by air, and / or mechanically entangled together). According to certain embodiments of the present invention, such a fiber web may be considered as a "consolidated nonwoven fabric", "nonwoven fabric", or simply "fabric".

[0020] The term "air-bonded" as used herein may include nonwoven fiber webs bonded by an bonding process (e.g., "air-bonded"), wherein hot air is used to fuse fibers at the surface of the fiber web and optionally within the fiber web. By way of example only, hot air may be blown through the fiber web in a conveyor oven or drawn through the fiber web by creating a vacuum as it passes through a porous drum. The temperature and rate of the hot air are parameters that can determine the level or degree of bonding in the nonwoven fiber web. According to certain embodiments of the invention, the temperature of the hot air may be high enough to (i) melt and / or fuse the bonded fibers dispersed throughout the matrix fibers without melting the matrix fibers, and / or (ii) melt and / or fuse the first polymeric component (e.g., sheath component) of a multi-component fiber (e.g., a bi-component fiber) without melting the second polymeric component (e.g., the sheath component) of the multi-component fiber.

[0021] As used herein, the terms "regionally bonded" and "regionally bonded" can refer to a thermal consolidation process in which a nonwoven fiber web is consolidated by a smooth hot rolling mill over at least one outermost surface of the nonwoven fiber web under pressure and heated, resulting in a greater proportion of fusion between the fibers forming the nonwoven fiber web compared to hot spot bonding. For example, two or more smooth rollers can be designed to heat the entire surface of at least one outermost surface of the nonwoven fiber web. In embodiments that include bonding fibers (e.g., having a relatively low melting point) dispersed throughout the matrix fibers (e.g., having a melting point higher than that of the bonding fibers), the bonding fibers create bonded sites at all or most of the intersections between the bonding fibers and the matrix fibers.

[0022] As used herein, the term "spunbond" can include fibers formed by extruding molten thermoplastic material from a plurality of fine, typically circular capillaries of a spinning nozzle into filaments, the diameter of which then rapidly decreases. According to embodiments of the invention, spunbond fibers are generally non-sticky when deposited onto a collection surface and are generally continuous, as disclosed and described herein. It should be noted that the spunbond material used in certain composites of the invention may include nonwovens described in the literature as SPINLACE®. Spunbond fibers may, for example, include continuous fibers.

[0023] As used herein, the term "continuous fiber" refers to a fiber that has not been cut from its original length before being formed into a nonwoven fiber web or nonwoven fabric. Continuous fibers may have an average length ranging from more than about 15 centimeters to more than 1 meter, up to the length of the fiber web or fabric formed. For example, as used herein, continuous fibers may include fibers in which the length of the fiber is at least 1,000 times greater than the average diameter of the fiber, such as at least about 5,000, 10,000, 50,000, or 100,000 times greater than the average diameter of the fiber.

[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 capillaries into aggregated high-speed, typically hot, gas (e.g., air) streams. These gas streams draw the molten thermoplastic material into thinner filaments to reduce their diameter, which may be the diameter of microfibers. According to embodiments of the invention, the die capillaries may be circular. The meltblown fibers are then carried by the high-speed gas stream and deposited on a collection surface to form a randomly distributed fiber web of meltblown fibers. The meltblown fibers may include microfibers, which may be continuous or discontinuous and are typically viscous when deposited on the collection surface. However, the length of meltblown fibers is shorter than that of spunbond fibers.

[0025] As used herein, the term "short fiber" can include cut fibers derived 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 polymeric fibers and / or elastomeric fibers. Non-limiting examples of materials may include polyolefins (e.g., polypropylene or polypropylene-containing copolymers), polyethylene terephthalate, and polyamide. By way of example only, the average length of short fibers can range from about 2 cm to about 15 cm.

[0026] As used herein, the term "multi-component fiber" can include fibers formed from two or more different polymeric materials or compositions, which are extruded from separate extruders but spun together to form a single fiber. The polymeric materials or compositions are disposed in substantially fixed positions across different regions of the cross-section of the multi-component fiber and extend continuously along the length of the multi-component fiber. As used herein, the term "bi-component fiber" can include fibers formed from two different polymeric materials or compositions, which are extruded from separate extruders but spun together to form a single fiber. The polymeric materials or compositions are disposed in substantially fixed positions across different regions of the cross-section of the multi-component fiber and extend continuously along the length of the multi-component fiber. Such multi-component fiber configurations can be, for example, sheath / core arrangements (where one polymer is surrounded by another polymer), eccentric sheath / core arrangements, side-by-side arrangements, pie arrangements, or "island" arrangements, each of which is known in the field of multi-component (including bi-component) fibers.

[0027] As used herein, the term “aspect ratio” includes the ratio of the length of the major axis to the length of the minor axis of the cross section of the fiber in question.

[0028] As used herein, the term "layer" may include generally identifiable combinations of similar material types and / or functions present in the XY plane.

[0029] All numerical endpoints disclosed herein that can generate a smaller range within the given range disclosed herein are within the scope of certain embodiments of the invention. For example, disclosures of about 10 to about 15 include 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; and so on. Furthermore, all single decimal endpoints (e.g., those reported as the nearest tenth) that can generate a smaller range within the given range disclosed herein are within the scope of certain embodiments of the invention. For example, disclosures of about 1.5 to about 2.0 include 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; and so on.

[0030] In one embodiment, the present invention provides a nonwoven fabric comprising a plurality of continuous matrix fibers having a first melting point and comprising a first polymeric material containing a first polymer component, wherein the first polymeric component comprises a first recycled polyester, such as first recycled polyester terephthalate (rPET). The nonwoven fabric may also comprise a plurality of adhesive fibers having irregular cross-sections randomly dispersed in the plurality of matrix fibers, wherein the plurality of adhesive fibers comprise a second polymeric material containing a second polymeric component. The second polymeric material has a second melting point lower than the first melting point. For example, the second polymeric component may have a melting point lower than the melting point of the first polymeric component. According to certain embodiments of the invention, the nonwoven fabric comprises a first ratio (weight of the plurality of continuous matrix fibers: weight of the plurality of adhesive fibers) between a plurality of continuous matrix fibers and a plurality of adhesive fibers. This first ratio may include about 80:10 to about 95:5, for example, at least about any of the following: 80:20, 82:18, 84:16, 85:15, 86:14, 88:12, 89:11, and 90:10, 91:9, 92:8, 93:7, 94:6, and 95:5. According to certain embodiments of the invention, the plurality of continuous matrix fibers comprises monocomponent fibers (e.g., each fiber is entirely formed from the same polymeric material).

[0031] According to certain embodiments of the present invention, the first polymeric material may include a total polymer content comprising about 40% by weight to about 100% by weight of the first polymeric component, for example at least about any one of the following: 40, 42, 45, 48, 50, 52, 55, 58, 60, 62, 65, 68 and 70% by weight of the first polymeric component, and / or at most about any one of the following: 100, 98, 95, 92, 90, 88, 85, 82, 80, 78, 75, 72 and 70% by weight of the first polymeric component.

[0032] According to certain embodiments of the present invention, the first polymeric material may include one or more additional polymeric components. For example, the one or more additional polymeric components may include a third polymeric component, such as additional rPET (e.g., third rPET) or virgin polyester (e.g., virgin PET). For example, the first polymeric material may include a blend of two polyesters (e.g., the first polymeric component and the third polymeric component), such as first rPET and virgin PET. For example, the first polymeric material may include about 0 to about 60% by weight of a third polymeric component, such as at least about any of the following: 0, 2, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28 and 30% by weight of a third polymeric component, and / or at most about any of the following: 60, 58, 55, 52, 50, 48, 45, 42, 40, 38, 35, 32, 30, 28, 25, 22 and 20% by weight of a third polymeric component.

[0033] According to certain embodiments of the invention, the plurality of continuous matrix fibers may have a circular cross-section having an aspect ratio of about 0.8 to about 1.2, for example, at least about any of the following: 0.8, 0.9, and 1, and / or at most about any of the following: 1.2, 1.1, and 1. Alternatively or additionally, the plurality of continuous matrix fibers may have a non-circular cross-section having an aspect ratio of at least about 1.5, for example, at least about any of the following: 1.5, 1.8, 2, 2.2, 2.5, 2.8, and 3, and / or at most about any of the following: 10, 9, 8, 7, 6, 5, 4, and 3. Continuous matrix fibers having a non-circular cross-section may include ribbon fibers, multi-leaf fibers, or mixtures thereof.

[0034] According to certain embodiments of the invention, the plurality of continuous matrix fibers may have an average cross-section of about 12 to about 36 micrometers, for example at least about any of the following: 12, 15, 18, 20, 22, 24 and 25 micrometers, and / or at most about any of the following: 36, 35, 32, 30, 28 and 25 micrometers. The average cross-section of the non-circular fiber is measured across the widest portion of the fiber being measured. Additionally or alternatively, the plurality of continuous matrix fibers may have an average denier per fiber (dpf) of about 3 to about 12 dpf, for example at least about any of the following: 3, 4, 5 and 6 dpf, and / or at most about any of the following: 12, 10, 9, 8, 7 and 6 dpf.

[0035] According to certain embodiments of the present invention, the first recycled polyester may include post-consumer waste, pre-consumer waste, and / or post-consumer waste. In this regard, as discussed above, at least a portion of the plurality of continuous matrix fibers may include recycled polyester fibers formed wholly or partially from post-consumer waste, pre-consumer waste, and / or post-consumer waste.

[0036] According to certain embodiments of the present invention, the plurality of adhesive fibers may include single-component short fibers, single-component continuous fibers, or combinations thereof. As described above, the plurality of adhesive fibers may include a second polymeric material, the second polymeric material comprising a second polymeric component. The second polymeric component may, for example, include a homopolymer or copolymer, such as a PET-containing copolymer. According to certain embodiments of the present invention, the second polymeric material and / or the second polymeric component has a melting point lower than that of the first polymeric material and / or the first polymeric component. The second polymeric component may, for example, include a second virgin polyester, such as virgin PET, virgin polypropylene or copolymers thereof, virgin polyethylene or copolymers thereof; or a second recycled polyester, such as second recycled polyester terephthalate (rPET), recycled polypropylene, or recycled polyethylene.

[0037] According to certain embodiments of the invention, the plurality of bonded fibers may include multi-component short fibers (e.g., bi-component short fibers), or multi-component continuous fibers (e.g., bi-component continuous fibers), or combinations thereof. According to certain embodiments of the invention, a second polymeric material may define at least a portion of the outermost surface of (i) the multi-component short fibers (e.g., bi-component short fibers), (ii) the multi-component continuous fibers (e.g., bi-component continuous fibers), and / or (iii) combinations thereof. As an example, the second polymeric material may define the sheath component of the bi-component short fibers, bi-component continuous fibers, or combinations thereof. Additionally or alternatively, the bi-component short fibers, bi-component continuous fibers, or combinations thereof may include multi-lobed fibers, wherein the second polymeric material defines at least a portion of the lobes of the multi-lobed fibers. For example, the second polymeric material is located at and defines the tip of the multi-lobed fiber.

[0038] According to certain embodiments of the present invention, the second melting point may be about 5°C to about 50°C lower than the first melting point, for example, at least about any of the following: 5, 6, 8, 10, 12, 14, 15, 16, 18 and 20°C lower than the first melting point, and / or at most about any of the following: 50, 45, 40, 35, 30, 28, 25, 22 and 20°C lower than the first melting point. Alternatively or concurrently, the nonwoven fabric may have a third ratio between a first melt flow rate (MFR) of about 1:50 to about 1:1.2 of the first polymer component and a second melt flow rate of the second polymer component, for example at least about any of the following: 1:50, 1:40, 1:30, 1:20, 1:10, 1:5 and 1:2, and / or at most about 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 and 1:1.5.

[0039] For example, the plurality of adhesive fibers may have been selectively at least partially melted and at least partially flowed to form an irregular cross-section present in the plurality of adhesive fibers, while the plurality of continuous matrix fibers are not melted. For example, FIG1A is an enlarged image of a nonwoven fabric including a plurality of continuous matrix fibers 10 and a plurality of adhesive fibers 20. As shown in FIG1A, the plurality of adhesive fibers 20 each have an irregular cross-section along the fiber length, wherein the second polymer has been partially melted and flowed or dispersed to interact with or contact the plurality of matrix fibers before re-solidifying and forming an adhesive web with the matrix fibers. For example, the plurality of adhesive fibers 20 may include narrow portions 22 that may appear to have a more defined geometry (e.g., a defined geometry, such as a circle) and larger or deformed portions 24, wherein the second polymer has been melted, flowed and re-solidified. FIG1B illustrates a plurality of continuous matrix fibers 10 having a trefoil cross-section.

[0040] According to certain embodiments of the present invention, the nonwoven fabric may include a nonwoven fabric bonded by air bonding (TAB), a nonwoven fabric bonded by hot zone bonding, or a nonwoven fabric bonded by hot spot bonding.

[0041] According to certain embodiments of the invention, the nonwoven fabric may have a fourth ratio between transverse tensile strength and longitudinal tensile strength of about 0.7:1 to about 1.3:1, for example, at least about any of the following: 0.7:1, 0.8:1, 0.9:1, 0.95:1, 0.98:1 and 1:1, and / or at most about any of the following: 1.3:1, 1.2:1, 1.1:1, 1.05:1, 1.02:1 and 1:1. The transverse tensile strength and longitudinal tensile strength are determined according to ASTM D44632-96.

[0042] According to certain embodiments of the invention, the nonwoven fabric may have a basis weight of about 5 to about 100 grams per square meter (gsm), for example at least about any of the following: 5, 6, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, 42, 45, 48 and 50 gsm, and / or at most about any of the following: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55 and 50 gsm.

[0043] In another embodiment, the present invention provides a method for manufacturing a nonwoven fabric, comprising the steps of: (a) forming a first polymeric melt having a first melting point and comprising a first polymeric material containing a first polymeric component, wherein the first polymeric component comprises a first recycled polyester, such as first recycled polyester terephthalate (rPET); (b) generating a second polymeric melt comprising a second polymeric material, the second polymeric material comprising a second polymeric component, wherein the second polymeric material has a second melting point below the first melting point; (c) melt-spinning the first polymeric melt through a first plurality of spinnerets of a spinning nozzle to form a plurality of continuous matrix fibers comprising the first polymeric material, and melt-spinning the second polymeric melt through a second plurality of spinnerets of a spinning nozzle to form a plurality of bonded fibers comprising the second polymeric material; (d) depositing the plurality of continuous matrix fibers and the plurality of bonded fibers onto a moving strip, wherein the plurality of bonded fibers are randomly dispersed within the plurality of continuous matrix fibers to provide a nonwoven fiber web; and (e) consolidating the nonwoven fiber web to form a nonwoven fabric, such as those described and disclosed herein.

[0044] According to certain embodiments of the present invention, the step of consolidating the nonwoven fiber web may include subjecting the nonwoven fiber web to a temperature above a second melting point and below a first melting point. In this regard, the consolidation step may selectively at least partially melt and induce at least partial flow of the plurality of bonded fibers without melting the plurality of continuous matrix fibers. According to certain embodiments of the present invention, the step of consolidating the nonwoven fiber web may include subjecting the nonwoven fiber web to a heat-bonded (TAB) operation. Additionally or alternatively, the step of consolidating the nonwoven fiber web may include subjecting the nonwoven fiber web to a hot-zone bonded operation. Additionally or alternatively, the step of consolidating the nonwoven fiber web may include subjecting the nonwoven fiber web to a hot-spot bonded operation. As described above, the step of consolidating the nonwoven fiber web may include: softening or melting a second polymer component, and allowing or inducing at least a portion of the second polymer component to flow, such that the plurality of bonded fibers have an irregular cross-section.

[0045] According to certain embodiments of the invention, the first polymeric material may have a first intrinsic viscosity (IV) from 0.6 to about 1n as determined by ASTM D5225, for example at least about any of the following: 0.6, 0.62, 0.64, 0.65, 0.68 and 0.7n, and / or at most about any of the following: 1, 0.95, 0.9, 0.85, 0.8, 0.78, 0.76, 0.75, 0.74, 0.72 and 0.7n. Alternatively or concurrently, the second polymeric material may have a second IV of from 0.5 to about 0.8 n as determined by ASTM D5225, for example at least about any of the following: 0.5, 0.52, 0.55, 0.58, and 0.6 n, and / or at most about any of the following: 0.8, 0.78, 0.76, 0.75, 0.74, 0.72, 0.7, 0.68, 0.65, 0.62, and 0.6 n. According to certain embodiments of the invention, the first IV may be greater than the second IV.

[0046] According to certain embodiments of the invention, the method may further include an annealing (e.g., hot annealing) step of the nonwoven fiber web prior to the step of consolidating the nonwoven fiber web. For example, the step of annealing the nonwoven fiber web may include raising the temperature of the nonwoven fiber web to within about 7°C below a second melting point, for example, within about 6°C, 5°C, 4°C, or 3°C below the second melting point or the first melting point. According to certain embodiments of the invention, as the temperature of the nonwoven fiber web increases, the nonwoven fiber web may be physically confined (e.g., between two belts, or between a strip and a drum, or by a type of tenter frame). According to certain embodiments of the invention, before releasing the nonwoven fiber web from the confinement, the temperature of the nonwoven fiber web may be reduced (e.g., passively or actively) to about 30°C (e.g., from about 20°C to about 35°C) to complete the annealing step. For example, the step of allowing or actively reducing the temperature of the nonwoven fiber web to a lower temperature before releasing it from physical constraints may include reducing the temperature of the nonwoven fiber web to about 20°C to about 35°C, for example, at least about any of the following: 20, 22, 25, and 28°C, and / or at most about any of the following: 35, 32, 30, and 28°C. According to certain embodiments of the invention, the step of annealing the nonwoven fiber web may only increase the adhesiveness of the second polymeric material.

[0047] According to certain embodiments of the invention, the nonwoven fiber web can undergo the annealing operation under conditions sufficient to increase only the adhesiveness of the plurality of bonding fibers, in order to promote adhesion to the plurality of continuous matrix fibers before the nonwoven fiber web enters, for example, a TAB operation, in order to reduce the shrinkage typically associated with the TAB operation.

[0048] In another embodiment, the present invention provides a drying sheet comprising a nonwoven substrate containing a nonwoven fabric as disclosed and described herein, and a fabric conditioning agent disposed on the nonwoven substrate. According to certain embodiments of the invention, once the drying temperature inside the tumble dryer is greater than about 120°F, at least a portion of the fabric conditioning agent is transferred from the nonwoven substrate to the garment.

[0049] Fabric conditioning agents may include, for example, quaternary ammonium compounds. According to certain embodiments of the invention, fabric conditioning agents may include at least one of alkylated quaternary ammonium compounds, cyclic or cyclic quaternary ammonium compounds, aromatic quaternary ammonium compounds, bisquaternary ammonium compounds, alkylated quaternary ammonium compounds, amidoamine quaternary ammonium compounds, ester quaternary ammonium compounds, and mixtures thereof. Alternatively or additionally, fabric conditioning agents may include tallow-based quaternary ammonium compounds or plant-based quaternary ammonium compounds.

[0050] In another embodiment, the present invention provides a filter comprising a filter medium including a nonwoven fabric as described and disclosed herein, wherein the nonwoven fabric is housed within a frame. According to certain embodiments of the invention, the filter medium may include a plurality of pleats formed therein.

[0051] According to certain embodiments of the invention, the filter medium may include at least one filter layer comprising one or more meltblown layers, one or more melt-fiberized layers, one or more submicron-containing nonwoven layers, or any combination thereof. For example, at least one filter layer may be supported on a nonwoven fabric. According to certain embodiments of the invention, the filter medium may include a first nonwoven fabric, such as those described and disclosed herein; a second nonwoven fabric, such as those described and disclosed herein; and at least one filter layer, wherein the at least one filter layer is located between the first nonwoven fabric and the second nonwoven fabric. In this respect, the fibers of the at least one filter layer may individually lack structural integrity, but structural integrity and protection are provided by the first nonwoven fabric and / or the second nonwoven fabric.

[0052] According to certain embodiments of the present invention, the filter medium may include at least one filter layer comprising a polymeric membrane supported on a nonwoven fabric. The polymeric membrane may, for example, include an ultrafiltration membrane, a nanofiltration membrane, or a reverse osmosis membrane.

[0053] According to certain embodiments of the present invention, the filter includes an air filter or a face mask. Alternatively, the filter may include a liquid filter, such as water filtration (e.g., swimming pool, spa, residential water filtration, and industrial water filtration), or filtration of organic liquids. Examples

[0054] The following examples further illustrate the content of this disclosure, and these examples should not be construed as limiting. That is, the specific features described in the following examples are illustrative rather than limiting.

[0055] An initial set of tests was conducted on two rolls of nonwoven fabric produced according to certain embodiments of the present invention. For each roll, the nonwoven fabric consisted of 89% by weight of matrix fibers and 11% by weight of adhesive fibers, the matrix fibers being formed from a mixture of 50% by weight of rPET and 50% by weight of first virgin PET, and the adhesive fibers being formed from a second virgin PET having a melting point lower than rPET and the first virgin PET. In this respect, based on the total weight of the fibers, each roll of nonwoven fabric comprised 44.5% by weight of rPET.

[0056] Four 9" x 6.4" slices were cut from each roll to provide a total of eight samples (i.e., four per roll). Each sample was initially weighed, and then a release coating with a target weight of 1.4g was applied to each sample. After application, each coated sample was weighed to determine the precise weight of the release coating on each sample.

[0057] Each sample was subjected to a series of wash and dry cycles using an Amana Super Capacity Plus (3.3 cubic feet) washer and an Amana Super Capacity Plus (7.1 cubic feet) dryer. Specifically, the dryer timed cycles included: (i) 5-minute intervals until a total drying time of 20 minutes was reached; (ii) single 10-minute intervals until a total drying time of 30 minutes was reached; and (iii) 15-minute intervals for the remaining drying time until a total drying time of 75 minutes was reached. Table 1 shows the average weight percentage of coating peeled off from the first four samples associated with the first roll and the average weight percentage of coating remaining on the samples, while Table 2 shows the data obtained for the samples associated with the second roll. Figures 2 and 3 show graphical representations of the data shown in Tables 1 and 2. In particular, Figure 2 shows the weight percentage of coating peeled off from the samples as a function of drying time, and Figure 3 shows the weight percentage of coating remaining on the samples as a function of drying time. Table 1 Table 2

[0058] Next, the comparative dry sheet designated as 2055U in the table and figure underwent the same test methods outlined below. The comparative dry sheet was formed from the same percentage of matrix fibers (i.e., 89 wt%) and binding fibers (i.e., 11 wt%), wherein the matrix fibers consisted of 25 wt% rPET and the remainder was virgin PET, and the binding fibers were formed entirely from PET homopolymer. Table 3 provides data related to the weight percentage of coating peeled off the comparative dry sheet and the average data for each of the eight samples discussed above. Figure 4 shows a graphical comparison of the data listed in Table 3. Table 3

[0059] Next, the breaking strength and elongation at break of multiple samples of the comparative dried sheet samples were determined. The data from these tests are shown in Table 4, where both breaking strength and elongation at break were measured according to ASTM D3822. Furthermore, the fiber dimensions of these samples were evaluated for the average diameter of the trilobal fibers and the dpf under a scanning electron microscope. This data is shown in Table 5. Table 4 Table 5

[0060] The fracture strength and elongation at fracture of the eight samples initially discussed were determined in the same manner. Data from these tests are shown in Table 6, where the fracture strength and elongation at fracture were measured according to ASTM D3822. Furthermore, the fiber size of these samples was evaluated based on the average diameter of the trefoil fibers and dpf under a scanning electron microscope. This data is shown in Table 7. Table 6 Table 7

[0061] Those skilled in the art can make these and other modifications and variations to the invention without departing from the spirit and scope of the invention as more specifically set forth in the appended claims. Furthermore, it should be understood that 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 illustrative and is not intended to limit the invention as further described in the appended claims. Therefore, the spirit and scope of the appended claims should not be limited to the exemplary descriptions of the versions contained herein. [Simplified Explanation of the Diagram]

[0009] The invention will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, embodiments of the invention. In fact, the invention 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 so that this disclosure will satisfy applicable legal requirements. The same numerals always refer to the same elements, and wherein: FIG1A illustrates a nonwoven fabric according to certain embodiments of the invention; FIG1B illustrates an image of a trilobal matrix fiber according to certain embodiments of the invention; FIG2 is a data graph comparing the coating peel percentage from two working examples; FIG3 is a data graph comparing the coating retention percentage from two working examples of FIG2; FIG4 is a data graph comparing the average coating peel percentage from the two working examples of FIG2 with a comparative example.

Claims

1. A nonwoven fabric, comprising: (i) a plurality of continuous matrix fibers comprising a first polymeric material, the first polymeric material comprising a first polymeric component, wherein the first polymeric component comprises a first recycled polyester, such as a first recycled polyester terephthalate (rPET), wherein the first polymeric material has a first melting point; and (ii) a plurality of adhesive fibers randomly dispersed in the plurality of matrix fibers and having an irregular cross-section, the plurality of adhesive fibers comprising a second polymeric material, the second polymeric material comprising a second polymeric component, wherein the second polymeric material has a second melting point lower than the first melting point.

2. The nonwoven fabric as claimed in claim 1, wherein the nonwoven fabric comprises a first ratio (weight of the plurality of continuous matrix fibers: weight of the plurality of adhesive fibers) based on weight between the plurality of continuous matrix fibers and the plurality of adhesive fibers, the first ratio comprising about 80:10 to about 95:5, for example at least about any of the following: 80:20, 82:18, 84:16, 85:15, 86:14, 88:12, 89:11, and 90:10, 91:9, 92:8, 93:7, 94:6, and 95:

5.

3. The nonwoven fabric as claimed in claims 1 to 2, wherein the plurality of continuous matrix fibers comprise single-component fibers.

4. The nonwoven fabric as claimed in claims 1 to 3, wherein the first polymeric material further comprises a third polymeric component, wherein the third polymeric component comprises a third rPET or a virgin polyester, such as a virgin PET.

5. The nonwoven fabric as claimed in claims 1 to 4, wherein the plurality of continuous matrix fibers (i) have a circular cross-section having an aspect ratio of about 0.8 to about 1.2, for example at least about any of the following: 0.8, 0.9 and 1, and / or at most about any one of the following: 1.2, 1.1, and 1; or (ii) having a non-circular cross-section having an aspect ratio of at least about 1.5, for example at least about any of the following: 1.5, 1.8, 2, 2.2, 2.5, 2.8 and 3, and / or at most about any one of the following: 10, 9, 8, 7, 6, 5, 4 and 3.

6. The nonwoven fabric as claimed in claim 5, wherein the plurality of continuous matrix fibers comprise ribbon fibers, multileaf fibers, or a mixture thereof.

7. The nonwoven fabric as claimed in claims 1 to 6, wherein the plurality of continuous matrix fibers have an average cross-section of about 12 to about 36 micrometers, for example at least about any of the following: 12, 15, 18, 20, 22, 24 and 25 micrometers, and / or at most about any of the following: 36, 35, 32, 30, 28, 25 micrometers; an average denier per fiber (dpf) of about 3 to about 12 dpf, for example at least about any of the following: 3, 4, 5 and 6 dpf, and / or at most about any of the following: 12, 10, 9, 8, 7 and 6 dpf, or both; and wherein.

8. A method for manufacturing a nonwoven fabric, comprising: (a) forming a first polymer melt comprising a first polymeric material comprising a first polymer component comprising a first recycled polyester, such as a first recycled polyester terephthalate (rPET), wherein the first polymeric material has a first melting point; (b) generating a second polymer melt comprising a second polymeric material comprising a second polymer component, wherein the second polymeric material has a second melting point lower than the first melting point; (c) melt-spinning the first polymer melt through a first plurality of spinnerets of a spinning nozzle to form a plurality of continuous matrix fibers comprising the first polymeric material, and melt-spinning the second polymer melt through a second plurality of spinnerets of the spinning nozzle to form a plurality of bonded fibers comprising the second polymeric material; (d) depositing the plurality of continuous matrix fibers and the plurality of bonded fibers onto a moving strip, wherein the plurality of bonded fibers are randomly dispersed within the plurality of continuous matrix fibers to provide a nonwoven fiber web; and (e) consolidating the nonwoven fiber web to form the nonwoven fabric.

9. The method of claim 8, wherein the step of consolidating the nonwoven fiber web includes subjecting the nonwoven fiber web to a temperature above the second melting point and below the first melting point.

10. The method of claim 9, wherein the step of consolidating the nonwoven fiber web includes subjecting the nonwoven fiber web to an air-bonding (TAB) operation or subjecting the nonwoven fiber web to a thermal zone bonding operation.

11. The method as described in claims 8 to 10, wherein the step of consolidating the nonwoven fiber web comprises: The second polymer component is softened or melted, and at least a portion of the second polymer component is allowed or induced to flow, such that the plurality of adhesive fibers have an irregular cross-section.

12. The method of claims 8 to 11 further includes a step of annealing the nonwoven fiber web prior to the step of consolidating the nonwoven fiber web, wherein the step of annealing the nonwoven fiber web includes raising the temperature of the nonwoven fiber web to within about 7°C below the second melting point, for example, within about 6°C, 5°C, 4°C or 3°C below the second melting point.

13. The method of claim 12, wherein the nonwoven fiber web is under physical constraints during the step of annealing the nonwoven fiber web, and the method further includes: A step of allowing or actively reducing the temperature of the nonwoven fiber web to a lower temperature before releasing the nonwoven fiber web from the physical constraints.

14. A dried sheet, comprising: (i) A nonwoven substrate comprising a nonwoven fabric as described in any one of claims 1 to 7; (ii) a fabric conditioner disposed on the nonwoven substrate.

15. A filter comprising: A filter medium comprising a nonwoven fabric as described in any one of claims 1 to 7, wherein the nonwoven fabric is contained within a frame.

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