EP4144901A2 - Fibre chargeable séparable, fibre multicomposant séparée, fibre à composants multiples séparée avec une charge durable, tissu non tissé, filtre et fil contenant cette fibre, et procédés de fabrication correspondants - Google Patents

Fibre chargeable séparable, fibre multicomposant séparée, fibre à composants multiples séparée avec une charge durable, tissu non tissé, filtre et fil contenant cette fibre, et procédés de fabrication correspondants Download PDF

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Publication number
EP4144901A2
EP4144901A2 EP21212071.1A EP21212071A EP4144901A2 EP 4144901 A2 EP4144901 A2 EP 4144901A2 EP 21212071 A EP21212071 A EP 21212071A EP 4144901 A2 EP4144901 A2 EP 4144901A2
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EP
European Patent Office
Prior art keywords
fiber
split
splittable
denier
multicomponent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP21212071.1A
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German (de)
English (en)
Other versions
EP4144901A3 (fr
Inventor
Jeffrey S. Dugan
Scott Christopher Keeler
William Cameron Miller
Robert Gillion Sanders
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fiber Innovation Technology Inc
HDK Industries Inc
Original Assignee
Fiber Innovation Technology Inc
HDK Industries Inc
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Publication date
Application filed by Fiber Innovation Technology Inc, HDK Industries Inc filed Critical Fiber Innovation Technology Inc
Publication of EP4144901A2 publication Critical patent/EP4144901A2/fr
Publication of EP4144901A3 publication Critical patent/EP4144901A3/fr
Withdrawn legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
    • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
    • D01F8/06—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyolefin as constituent
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/08—Melt spinning methods
    • D01D5/096—Humidity control, or oiling, of filaments, threads or the like, leaving the spinnerettes
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00—General methods for the manufacture of artificial filaments or the like
    • D01F1/02—Addition of substances to the spinning solution or to the melt
    • D01F1/10—Other agents for modifying properties
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
    • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
    • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
    • D01F8/12—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyamide as constituent
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
    • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
    • D01F8/14—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyester as constituent
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
    • D04H1/4382—Stretched reticular film fibres; Composite fibres; Mixed fibres; Ultrafine fibres; Fibres for artificial leather
    • D04H1/43825—Composite fibres
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
    • D04H1/4382—Stretched reticular film fibres; Composite fibres; Mixed fibres; Ultrafine fibres; Fibres for artificial leather
    • D04H1/43825—Composite fibres
    • D04H1/43828—Composite fibres sheath-core
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
    • D04H1/4382—Stretched reticular film fibres; Composite fibres; Mixed fibres; Ultrafine fibres; Fibres for artificial leather
    • D04H1/43825—Composite fibres
    • D04H1/43832—Composite fibres side-by-side
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
    • D04H1/4391—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece characterised by the shape of the fibres
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
    • D06M10/02—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements ultrasonic or sonic; Corona discharge
    • D06M10/025—Corona discharge or low temperature plasma
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
    • D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
    • D06M13/224—Esters of carboxylic acids; Esters of carbonic acid
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
    • D06M13/52—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment combined with mechanical treatment
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M2200/00—Functionality of the treatment composition and/or properties imparted to the textile material
    • D06M2200/40—Reduced friction resistance, lubricant properties; Sizing compositions

Definitions

  • the current invention relates to the field of splittable fibers and manufacturing processes therefor. More particularly the current invention relates to the field of splittable fibers formed of a multicomponent staple fiber and manufacturing processes therefor.
  • Fibers are typically spun, drawn, and textured prior to being spun into a yarn. Often such artificial fibers are textured by crimping prior to use as crimping provides benefits such as processability (carding in particular), improved skin feel, softness, stretch, fluffiness, etc. to the fibers.
  • the fibers may be selected for various properties, such as chemical resistance, fluffiness, surface area, hydrophobicity/hydrophilicity, etc.
  • Carded fibers are known for use in filtration media and other uses, via mechanical filtration principles such as diffusion, interception, inertial impaction and sieving to capture and retain particles of various sizes.
  • Splittable fibers having an increased surface area are also known for use in filtration media, leading to a reduced pore size with the same amount of material which leads to higher filtration efficiency in the Z direction of the filter media.
  • Splittable fibers are known in the art to produce sub-fibers which have an increased surface area, and therefore different properties than the original (single-strand) splittable fiber itself. Such splittable fibers are typically produced from a multicomponent fiber which is then split into multiple sub-fibers.
  • the multicomponent fibers are known to contain mixtures of polymers, a charge-enhancing additive, a filler, a finish material, etc. to create the splittable fiber. See, e.g., US Patent No.
  • splittable fibers and corresponding processes are known to produce fibers which have a significantly larger surface are when split into sub-fibers. Either before or after splitting, these fibers may be then formed into, for example, filters, filter materials, nonwoven fabrics/materials, etc. Such splittable fibers are especially useful in filters, filter materials, etc. where the splittability of the fibers can significantly increase filtration efficiency. Similarly, higher water pressure during hydroentanglement may lead to higher splitting, but may conversely also create "large" apertures throughout the nonwoven fabric which then in turn decreases the filtration efficiency.
  • nonwoven fabrics, and the split fibers therein are typically not chargeable, and certainly are not capable of holding a durable charge, which also reduces their potential filtration efficiency. Accordingly, the filtration efficiency of current splittable fibers is limited by their lack of charge/chargeability. See, for example, US 2015/0343455 A1 by Schultz, et al., to 3M Innovative Properties Co., published on December 3, 2015 , hereby incorporated by reference in its entirety.
  • Nano fiber-based filter media are formed by depositing fine fibers onto the surface of a pleatable support layer making a physical filtration structure that relies upon sieving only.
  • the fibers are very sensitive and it is difficult to get them to adhere to the surface of the support layer.
  • the fibers act as a high surface area membrane would, by basically surface loading contaminant particles. As soon as the surface blinds off or builds a "dirt cake" the resistance increases to maximum and the filter media has difficulty maintaining airflow.
  • nano fiber-based filters are known to typically cost up twice what other filters cost.
  • structures that rely only on a high charge potential such as "Tribo electret media” are designed to be of very low air resistance but have a very powerful surface charge.
  • the advantage from this type of media is that they "depth load” particulates and possess a long life with only a small increase of resistance over many weeks or even months.
  • a filter made with this fibers ingests an oily smoke from cigarettes or forest fires, the charge is quickly masked, and the filter rapidly loses efficiency.
  • These filters have been mis-applied and placed in commercial buildings where the filters prematurely fail due to the loss of charge when the building ventilation system becomes contaminated with cigarette smoke.
  • the EU has recognized this mis-application and has initiated the new ISO 16890 standard, hereby incorporated by reference in its entirety, where the filter is given a rating by averaging the beginning efficiency, discharging the media and retesting.
  • the results are quite dramatic for a media like Tribo electret where it may have an initial efficiency of MERV 13 but after discharging may end up with a MERV 6.
  • finish materials currently used are intended to reduce static build up in the nonwoven fabric, they also may cause the splittable fiber to quickly lose the charge after, for example, electret charging via corona processing.
  • current splittable fibers are not known to be charged, or to durably carry an electret charge. This in turn has been now found to limit their filtration efficiency. Accordingly, there exists a need for a finish material for splittable fibers which does not cause the splittable fiber to lose charge.
  • a splittable chargeable fiber capable of holding a durable charge, especially for the production of filtration media, a nonwoven fabric made therefrom, and processes for forming such a splittable chargeable fiber and nonwoven fabric.
  • a process to manufacture a splittable chargeable fiber capable of holding a durable charge There also exists a need for a filtration product which possesses the advantages of a nano fiber-based filter and a charged filter to provide efficient and lasting filtration.
  • An embodiment herein relates to a process for forming a splittable fiber having the steps of providing a multicomponent fiber; or a multicomponent staple fiber, providing a finish material, and at least partially coating the multicomponent fiber with the finish material to form a splittable fiber.
  • the multicomponent fiber; or a multicomponent staple fiber contains a first thermoplastic segment comprising polymer component A and a second thermoplastic segment comprising polymer component B.
  • the finish material has an evaporation point of less than about 160 °C.
  • An embodiment of the present invention relates to a process for forming a nonwoven fabric having the steps of providing a splittable fiber by providing a multicomponent fiber; or a multicomponent staple fiber as described herein, and forming the splittable fiber into a nonwoven fabric.
  • An embodiment of the present invention relates to a split multicomponent fiber comprising a durable charge.
  • An embodiment of the present invention relates to a nonwoven fabric, a filter and/or a spun yarn formed by the fibers and processes described herein.
  • the present invention may provide a splittable fiber which is capable of receiving and maintaining / holding a durable charge. This splittable fiber may then be further formed into, for example, a filtration media possessing significant advantages over existing filtration media.
  • the present invention may provide surprising benefits by combining the best advantages of nano fiber-based filters and electret-charged filters by incorporating high surface area physical filtration and electret charge to enhance fine particle retention.
  • the present invention is believed to provide both depth load filtration and to maintain long-lasting performance with little or no resistance spikes. It is believed that the present invention significantly reduces the chances of prematurely failure due to, for example, cigarette smoke, while also providing significant manufacturing and cost advantages.
  • the invention herein may provide one or more benefits such as improved filter loading, improved filter life, improved MERV rating, improved resilience/scuff resistance, etc.
  • durable charge indicates an electret charge that retains at least 90% of the original charge after at least about 1 year; or at least about 2 years; or at least about 3 years, in normal conditions of packaging, storage and handling.
  • a simple hand held static measuring device can be used to measure the initial charge after electret charging, and the retained charge after the above period of time, and the percentage retention is easily calculated.
  • electrostatic refers to a material that exhibits a quasi-permanent electric charge.
  • multicomponent fiber indicates a fiber that has been formed from a plurality of component polymers, or the same polymer having different properties and/or additives, and extruded as separate sub-fibers (i.e., strands) from separate extruders.
  • the multicomponent fiber will be made from a plurality of different component copolymers; or each sub-fiber is made from a different polymer from that of the adjacent sub-fiber(s).
  • the sub-fibers are then combined to form a single fiber, for example, by spinning.
  • the sub-fibers are arranged in consistently-positioned positions across the cross-section of the multicomponent fiber.
  • the relative positions of the sub-fibers may be in, for example, pie-wedges such as seen in Figs 1a-1c , stripes, etc. as known in the art. See, for example, US Patent No. 5,108,820 to Kaneko, et al., assigned to Mitsubishi Petrochemical Industries, granted on April 28, 1992 , hereby incorporated herein by reference in its entirety.
  • nonsplittable fiber indicates a fiber having a single, relatively fixed and constant denier along substantially its entire length even after processing, including, for example, carding, hydroentanglement, etc., into a nonwoven web.
  • the nonsplittable fiber is a fiber having a roughly circular cross-sectional shape in which the entire fiber surface comprises a single polymer to a depth of at least 10% of the fiber's maximum radius; or for a non-circular cross sectional fiber, such as a trilobal fiber, wherein a single polymer comprises substantially the entire fiber surface.
  • splittable fiber indicates that a multicomponent fiber having a given width and cross-sectional configuration may be changed after fiber extrusion, substantially as part of the nonwoven fabric formation process, typically through physical disruption of the attachment between individual sub-fibers by the application of mechanical energy.
  • a splittable fiber herein will split into at least 2 sub-fibers for about 20% or more; or for about 30% or more of its length; or for about 40% or more of its length after a typical carding process having a main cylinder : worker roll speed ratio of 20:1; or 15:1; or 10:1 at a given output speed.
  • staple fiber indicates a fiber; typically an extruded fiber, which may be from about 1.25 cm to about 16 cm in length typically, due to cutting. Staple fibers are typically then formed into a nonwoven fabric via one or more forming processes such as carding, air laying, adhesive bonding, thermal bonding, etc.
  • An embodiment of the present invention relates to a process for forming a splittable fiber having the steps of providing a multicomponent fiber; or a multicomponent staple fiber, providing a finish material, and at last partially coating the multicomponent fiber, or the multicomponent staple fiber, with the finish material.
  • the multicomponent staple fiber contains a first thermoplastic segment containing polymer component A, and a second thermoplastic segment containing polymer component B.
  • the finish material has an evaporation point of less than 160 °C.
  • the polymer component A and polymer component B are typically useful herein when a carded web made from a pie wedge fiber made from the polymer pair is observed to contain at least 20% of the pie wedge fibers that have split to any degree after carding. This typically means that polymer component A and polymer component B have different empirical chemical formulas. Without intending to be limited by theory, it is believed that, for example, two different grades of polypropylene with different molecular weights would have the same empirical chemical formula and would not be sufficiently different for 20% or more of the pie wedge fibers to split during carding.
  • PET polyethylene terephthalate
  • isophthalic acid/terephthalic acid coPET would have identical empirical chemical formulas (but not identical chemical structures) and would thus it would be unlikely for 20% or more of the pie wedge fibers to split during carding.
  • PET and polypropylene have different chemical formulas and are sufficiently different so as to function in the invention.
  • the present invention is operable and may provide a splittable fiber so long as the empirical chemical formula of polymer component A is significantly different from; or different from, polymer component B.
  • the multicomponent fiber; or multicomponent staple fiber, useful herein is a fiber having a plurality of thermoplastic segments; typically a first thermoplastic segment and a second thermoplastic segment, although additional thermoplastic segments may also be included, such as a third thermoplastic segment, a fourth thermoplastic segment, etc.
  • the multicomponent fiber typically contains at least 4 distinct thermoplastic segments; or from about 4 to about 128 distinct thermoplastic segments; or from about 8 to about 64 distinct thermoplastic segments, or from about 16 to about 32 distinct thermoplastic segments.
  • Each thermoplastic segment may be formed of polymer component A or polymer component B as desired, as long as at least one thermoplastic segment in the multicomponent fiber is formed of polymer component A, and at least one thermoplastic segment in the multicomponent fiber is formed of polymer component B.
  • each segment will be of a different polymer than the adjacent segment(s).
  • thermoplastic segments are typically arranged in the fiber such that they define a specific spatial arrangement within the fiber's cross section. Furthermore, this specific spatial arrangement typically does not vary significantly along the entire length of the multicomponent fiber prior to splitting. See, for example, embodiments of the multicomponent fiber herein containing multiple thermoplastic segments in Figs. 1a-1c ., showing cross-sectional views of various multicomponent fiber embodiments, where the multicomponent fiber, 10, contains a plurality of thermoplastic segments, 12, 12a, 12b, 12c, 12d, etc. each of which may correspond to a sub-fiber (see Fig. 2 at 14).
  • thermoplastic segments are typically coextruded together to form a single multicomponent fiber, although they may be separately extruded and then combined, typically quickly combined (before the individual thermoplastic segments harden), to form the multicomponent fiber.
  • Each thermoplastic segment has the potential to form its own sub-fiber (see Fig. 2 at 14) upon splitting.
  • a process for forming a nonwoven fabric includes the steps of providing a splittable fiber, and forming the splittable fiber into a nonwoven fabric.
  • the splittable fiber is provided by providing a multicomponent fiber; or a multicomponent staple fiber, containing a first thermoplastic segment containing a polymer component A, and a second thermoplastic segment containing a polymer component B, providing a finish material having an evaporation point of less than 160 °C and at least partially coating the multicomponent staple fiber with the finish material.
  • the step of forming the splittable fiber into a nonwoven fabric may be, for example, forming step is selected from the group consisting of carding, thermal bonding, needle punching, spunbonding/spinbonding, air laying, hydroentanglement, melt blowing, hydro pulping, refining, wet laying, passing thorough air oven, cross-lapping, and a combination thereof; or thermal bonding, needle punching, hydropulping, wet-laying, chemical bonding (e.g., for acrylic latex), melt blowing, air laying, carding, needling, hydroentanglement, and a combination thereof; or thermal bonding, needlepunching, hydropulping, wet laying, and a combination thereof.
  • forming step is selected from the group consisting of carding, thermal bonding, needle punching, spunbonding/spinbonding, air laying, hydroentanglement, melt blowing, hydro pulping, refining, wet laying, passing thorough air oven, cross-lapping, and a combination thereof.
  • forming step includes all different phases of the physical forming process, from the point that fibers are extruded, to the final production of the nonwoven fabric. However, the forming process as used herein does not necessarily include the electret charging step.
  • multicomponent fiber when the multicomponent fiber splits apart into sub-fibers, they do so in a distribution of splitting at any specific location along the multicomponent fiber (see, e.g., Fig. 2 and Fig. 3 ). That is, for example, at a certain location, a multicomponent fiber comprising 16 thermoplastic segments may split entirely into 16 separate sub-fibers, with each sub-fiber containing a single thermoplastic segment.
  • a multicomponent fiber may split into 6 sub-fibers each containing one thermoplastic segment each, 2 sub-fibers comprising 2 thermoplastic segments each (not split apart from each other), and one sub-fiber comprising 6 thermoplastic segments that remain adhered to each other in a single sub-fiber.
  • the distribution of single-segment and multiple segment sub-fibers may be different.
  • Fig. 2 shows a partial side view of an embodiment of a splittable fiber, 20, of the present invention after splitting.
  • the multicomponent fiber, 10, contains 8 different thermoplastic sub-fibers, 12a-12h from top to bottom respectively, to form the splittable fiber, 20.
  • thermoplastic segments 12a, 12b, 12c, 12d, and 12e are joined together in a sub-fiber 14a, while thermoplastic segments 12f, 12g and 12h are joined together in a sub-fiber, 14b.
  • the split distribution can be measured using, for example, the BET test, the Micronaire test, SEM analysis, etc. as described herein.
  • thermoplastic segment 12a has split from thermoplastic segments 12b and 12c which are still joined together.
  • Thermoplastic segment 12d and thermoplastic segment 12e are split as well as single sub-fibers, 14, while thermoplastic segments 12f, 12g, and 12h are still joined together in sub-fiber 14b.
  • thermoplastic segments 12a, 12b, 12c, 12d, 12e, 12f, 12g and 12h can all be seen and identified separately as individual sub-fibers.
  • thermoplastic segments are joined together as a single multicomponent fiber.
  • thermoplastic segments are also possible as well, either in different multicomponent fibers, or at different places in the same multicomponent fiber.
  • splittable fiber having a variable split distribution is useful as it allows the production of various nonwoven fabrics having different physical features and properties such as fluffiness, thickness, insulation levels, air/water resistance, filtration levels, etc. from the same multicomponent fiber.
  • split distribution can be increased by changing the process, for example, more vigorous carding leads to a higher splitting of the splittable fibers, both along the same fiber as well as in different fibers.
  • Fig. 3 shows a partial side view of an embodiment of a splittable fiber of the present invention after splitting.
  • the splittable fiber, 20, can be shown split into thermoplastic segments, 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h, for a majority of its length.
  • the splittable fiber, 20, is split into thermoplastic segments, 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h, each of which corresponds to a sub-fiber, 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h.
  • Fig. 4 shows a cross-sectional view of a hollow multicomponent fiber, 10, containing a plurality of alternating thermoplastic segments, 12a and 12b.
  • the multicomponent fiber, 10, contains a hollow center, 16.
  • Each segment 12a is formed of polypropylene and in the embodiment of Fig. 4 each segment 12b is formed of polymethylpentene, which would normally bind together too strongly to be split when formed into a shape such as Fig. 1a .
  • the multicomponent fiber is a hollow fiber.
  • the polymer component A is polypropylene and polymer component B is polymethylpentene.
  • the polymer component A includes a polymer; or a polymer selected from the group consisting of a polyamide, a sulfur-containing polymer, an aromatic polyester, an aliphatic polyester, a polyolefin, and a combination thereof; or a polyamide, a polyphenylene sulfide, a polyarylene terephthalate, a polyarylene isopthalate, a polylactic acid, a polyhydroxyalkanoate an aliphatic polyester, a polypropylene, a polyethylene, a polymethylpentene, and a combination thereof; or nylon, polyphenylene sulfide, polyethylene terephthalate, polylactic acid, poly propylene, and a combination thereof; or PET, polylactic acid polymer, polypropylene, and a combination thereof.
  • the term "a combination thereof' specifically includes copolymers, homo
  • the polymer component B includes a polymer; or a polymer selected from the group consisting of a polyamide, a sulfur-containing polymer, an aromatic polyester, an aliphatic polyester, a polyolefin, and a combination thereof; or a polyamide, a polyphenylene sulfide, a polylactic acid, a polyarylene terephthalate, a polyarylene isopthalate, a polyhydroxyalkanoate an aliphatic polyester, a polypropylene, a polyethylene, a polymethylpentene, and a combination thereof; or a nylon, a polyphenylene sulfide, a polylactic acid, a polyethylene terephthalate, a poly propylene, and a combination thereof; or a PET, a polylactic acid polymer, a polypropylene, and a combination thereof.
  • the polymer component A and/or the polymer component B contains a polyolefin; or a polyolefin selected from the group consisting of a polypropylene, a polyethylene, and a combination thereof.
  • a polyolefin selected from the group consisting of a polypropylene, a polyethylene, and a combination thereof.
  • polyolefins; or polypropylene, polyethylene, and the combination thereof are especially useful for acquiring and holding an electret charge.
  • the polymer component A contains a polyolefin polymer
  • polymer component B contains a non-polyolefin polymer.
  • the polymer component A contains a polylactic acid polymer
  • polymer component B contains a non-polylactic acid polymer.
  • the finish material herein is applied to the surface of the splittable fiber to aid in lubricating the splittable fiber to reduce heat generation and to reduce static during further processing, such as carding, etc.
  • traditional finish materials contain mineral oils or synthetic oils with anti-static additives. Sometimes these traditional finish materials may contain animal fats, or fatty acids.
  • an embodiment of the invention herein includes the step of removing the finish material from the splittable fiber prior to electret charging; or removing the finish material from the splittable fiber during the electret charging process.
  • the finish material is removed during, for example, the dwell time in an oven, etc.
  • a finish material may be required for increasing lubrication during further processing, to reduce static charge build up, etc.
  • the finish material has an evaporation point of less than about 160 °C; or from about 30 °C to about 160 °C; or from about 40 °C to about 150 °C; or from about 50°C to about 100 °C.
  • the finish material herein may be a substantially water-soluble; or water-soluble finish material, which is especially intended to wash away during, for example, washing, a hydroentanglement process, etc.
  • the finish material is a water-soluble finish material, and the forming process includes the step of hydroentangling the splittable fiber while coated with the finish material.
  • the process herein includes the step of removing, by weight, at least a portion; or from about 50% to about 100% of the finish material; or from about 75% to about 100% of the finish material; or form about 80% to about 100% of the finish material, from the nonwoven fabric, the multicomponent fiber, and/or the splittable fiber; or from the splittable fiber, during or after the forming step when the splittable fiber is formed into a nonwoven fabric and prior to the electret charging process.
  • the nonwoven fabric forming process removes at least a portion of the finish material; or from about 50% to about 100% of the finish material; or from about 75% to about 100% of the finish material; or form about 80% to about 100% of the finish material; or substantially all of the finish material, by weight from the nonwoven fabric.
  • the finish material comprises water, a lubricant, and an emulsifier.
  • the lubricant is a selected from a plant-based oil, a natural oil, a synthetic oil, a water-soluble lubricant, and a combination thereof; or a vegetable oil, a mineral oil and a combination thereof; or a light vegetable oil, a light mineral oil, and a combination thereof; or a coconut oil, a corn oil, and a combination thereof. It is preferred that the lubricant herein possess a low molecular weight, a high viscosity, and few, or no molecular byproducts when exposed to heat, and no residue after evaporation.
  • finishing material and/or the lubricant are compliant with the United States Federal Drug Administration guidelines regarding GRAS (Generally Regarded As Safe) list (See, for example, https://www.fda.gov/food/food-ingredients-packaging/generally-recognized-safe-gras; and US Code of Federal Regulations: 21 CFR 177.2800; 21 CFR 176.210; 21 CFR 178.3400), all hereby incorporated by reference in its entirety.
  • GRAS Generally Regarded As Safe
  • the finish material is a water-soluble finish material; typically containing a water-soluble lubricant; or containing sufficient emulsifier to fully emulsify any and all oil in the finish material, or is a fully water-soluble finish material, so that during, for example, a hydroentanglement process, the finish material washes away; or substantially washes away, from the splittable fiber.
  • the emulsifier acts as an antistatic compound; or an antistatic compound having an evaporation point of less than about 160 °C; or from about 30 °C to about 160 °C; or from about 40 °C to about 150 °C; or from about 50°C to about 100 °C.
  • the finish material may contain a specific antistatic material other than the emulsifier.
  • the finish material may also contain a stabilizer, a thickener, a thinner, an anticoagulant, an antimicrobial compound and a combination thereof.
  • a stabilizer e.g., sodium citrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium sulfate, sodium bicarbonate, sodium sulfate, sodium sulfate, sodium sulfate, sodium sulfate, sodium sulfate, sodium sulfate, sodium sulfate, sodium sulfate, sodium sulfate, sodium sulfate
  • the multicomponent fiber is at least partially coated; or coated, in a coating step with the finish material to form a splittable fiber.
  • the coating step may include, for example, spraying the finish material onto the multicomponent fiber, immersing the multicomponent staple fiber in the finish material, contacting the fiber and a film of liquid finish material on the surface of a transfer roll (for example, a kiss-roll application process), contacting the fiber with a bead of the finish material as the fiber passes through a grooved applicator (e.g., using a metered-finish application process), and a combination thereof.
  • the process herein may further include the step of cutting a multicomponent fiber to form a multicomponent staple fiber, crimping a multicomponent staple fiber to a length of from about 1.25 cm to about 16 cm, and a combination thereof.
  • the splittable fiber is typically formed into a nonwoven fabric by, for example, by the forming processes described herein. Such forming processes are known in the art.
  • the splittable fiber is fully split into a plurality of sub-fibers.
  • the smallest sub-fibers have a linear density of less than about 5 denier; or less than about 2 denier; or less than about 1 denier; or less than about 0.8 denier; or less than about 0.4 denier.
  • the nonwoven web includes a nonsplittable fiber having a linear density of greater than about 1 denier; or from about 1.5 denier to about 4 denier; or from about 1.5 denier to about 3 denier.
  • the nonwoven fabric herein further contains an additional nonsplittable fiber having a linear density of from about 1 denier to about 20 denier to provide additional properties such as stiffness, the ability to hold a shape or a crease/fold, etc.
  • An embodiment of the present invention further includes a split multicomponent fiber having a durable charge as described herein.
  • the nonwoven fabric also contains a nonsplittable fiber in addition to the splittable fiber.
  • the process includes the step of providing a nonsplittable fiber.
  • the nonwoven web is then formed from the splittable fiber and the nonsplittable fiber.
  • the nonwoven fabric contains from about 1% to about 100%; or from about 3% to about 97%; or from about 5% to about 95%; or from about 10% to about 90% splittable fibers by weight of the nonwoven fabric. It is believed that a blend of both splittable fibers and nonsplittable fibers may provide benefits such as strength, shape retention, filtering, etc.
  • the nonwoven fabric contains at least 20% nonsplittable fibers, especially if it is thermal bonded during the forming step.
  • the finish material is removed after the forming step; or after the splittable fiber is split. Without intending to be limited by theory, it is believed that by removing the finish material from the splittable fiber, the nonwoven fabric, the split multicomponent fiber, etc. the resulting individual split multicomponent fiber's ability to acquire and hold a durable charge will not be significantly abated or reduced by the antistatic properties of the finish material.
  • the process for forming a nonwoven web includes the step of splitting the multicomponent fiber; or the multicomponent staple fiber; or the splittable fiber, into a split fiber.
  • the splitting step includes a needle punching process, a hydroentanglement process, a carding process, a flexing process, a twisting process, a stretching process, a drawing process, a scraping process, a crushing process, a rolling process, a hydropulping process, a stitchbonding/stitchbinding process, and a combination thereof; or a carding process, a needle punching process, a hydropulping process, and a combination thereof.
  • the splitting step is the same as the forming step.
  • the electret charging process charges a thermoplastic component in the splittable fiber, the split fiber, the multicomponent fiber, the multicomponent staple fiber, the nonwoven fabric, and/or etc. selected from the group of the first thermoplastic component, the second thermoplastic component, and a combination thereof; or the split fiber, the multicomponent fiber, the split multicomponent fiber, and/or the nonwoven fabric.
  • the electret charging process useful herein is selected from the group of corona charging, ion bombardment, atmospheric plasma deposition (APD), other charging methods, and a combination thereof; or corona charging, ion bombardment, APD and a combination thereof; or corona charging, APD, and a combination thereof.
  • Corona charging is known in the art and has its roots in the foil and film lamination process.
  • Dr. Peter Tsai from University of Tennessee developed and patented a system to enhance melt blown polypropylene with a similar technology designed to give films a normalized surface energy for secondary processing.
  • Dr. Tsai found that by applying a strong polarity of charge to a polypropylene melt blown structure that the surface energy attracted, removed and held fine particles (> 1.0 micron) enhancing an otherwise low efficiency filtration media.
  • the electret charging process includes the process of APD.
  • the electret charging process first employs an atmospheric plasma deposition process and subsequently a corona charging process.
  • APD may also remove oligomers and other low molecular weight by-products, such as the finish material, from thermoplastic polymeric fibers as well as providing a nano-etched finish giving the fibers a more suitable surface.
  • the APD process may actually clean and functionalize the fiber surface such that when the APD process is followed by a corona charging process, the corona charge may be stronger, and/or may last an even longer time; i.e., is even more durable.
  • the electret charging; or the corona charging process, ion bombardment, the APD process, other charging methods, and a combination thereof; or the heat from the corona charging process, the APD process, and a combination thereof helps to remove finish material from the splittable fiber, the nonwoven fabric, the multicomponent fiber, the multicomponent staple fiber, the split fiber, and/or sub-fiber.
  • the electret charging; or the corona charging imparts a negative charge to the outer surface of the splittable fiber, the nonwoven fabric, the split fiber, the multicomponent fiber, the multicomponent staple fiber, and/or sub-fiber.
  • this negative surface energy on the outer surface of the splittable fiber, the nonwoven fabric, the split fiber therefore attracts positively-charged particles from the air or other media passing through the filter, thereby significantly increasing filtration efficacy.
  • the electret charging may impart either a net negative charge or a net positive charge on the nonwoven fabric, the multicomponent fiber, multicomponent staple fiber, and/or the split fiber.
  • An electric charge allows the nonwoven fabric, the multicomponent fiber, the multicomponent staple fiber, and/or the split fiber to attract oppositely-charged particles when being used as, for example, a filtration matrix.
  • a charge-enhancing additive added is included into the multicomponent fiber; or the polymer component A; or the polymer component B.
  • the charge-enhancing additive enhances the development and/or retention of an electret charge; or a static electrical charge.
  • the charge-enhancing additive is selected from the group of stearate salts; phosphate metal salts, benzoic acid salts, zinc, and a combination thereof; or the charge-enhancing additive is selected from the group of calcium stearate, magnesium stearate, sodium phosphate, sodium benzoate, zinc salts, and a combination thereof; or the charge-enhancing additive is selected from the group of calcium stearate; magnesium stearate, sodium phosphate, and a combination thereof.
  • stearate salts or calcium stearate and magnesium stearate particles; or calcium stearate particles having a diameter of 5 microns ( ⁇ ) or less and magnesium stearate particles having a diameter of 5 ⁇ or less are especially desirable if the multicomponent fiber and/or a sub-fiber contains polypropylene.
  • the charge-enhancing additive(s) may form a capacitor-like structure which may enhance the electret charge density and/or durability as compared to when no charge-enhancing additive is present.
  • the charge-enhancing additive is an organic acid metal salt composed of at least a C 10 carbon-chain organic acid and a metal ion work function of 4eV or more.
  • organic acid useful herein include C 10 or higher carbon chain length carboxylic acids, organic phosphoric acids, organic sulfonic acids, and the like, especially lauric acid, linolenic acid, t-butylbenzoic acid, di-(t-butylphenyl) phosphoric acid, and/or stearic acid.
  • the metal salt ions useful herein include, for example, aluminum ions, iron ions, nickel ions, cobalt ions, tin ions, copper ions, lead ions, cadmium ions, etc., especially aluminum ions. See JP H06-254319A by Tokuda, et al., to TOYOBO Co., Ltd., published on September 13, 1994 hereby incorporated by reference in its entirety.
  • the charge-enhancing additive is selected from the group of triphenylmethanes; ammonium compounds and immonium compounds; intensely fluorinated ammonium and immonium compounds; biscationic acid amide and acid imide derivatives; polymeric ammonium compounds; diallylammonium compounds; arylsulfide compounds; phenolic compounds (respectively compounds of the CAS-No.
  • phosphonium compounds ; highly fluorine-substituted phosphonium compounds; calix(n)arene compounds; metal complex compounds like chromium-, cobalt-, iron-, zinc- or aluminum azocomplexes or chromium-, cobalt-, iron-, zinc- or aluminum salicyclic acid complexes (such as described by CAS-Numbers 31714-55-3 , 104815-18-1, 84179-68-8, 110941-75-8, 32517-36-5, 38833-00-00, 95692-86-7, 85414-43-3, 136709-14-3, 135534-82-6, 135534-81-5, 127800-82-2, 114803-10-0, 114803-08-6 and the like); benzimidazolon compounds; and/or azines of the following Color Index numbers, C.
  • the charge-enhancing additive contains an arylamino-substituted benzoic acid and/or an arylamino-substituted benzoic acid salt.
  • the salts useful herein may be metal-containing salts and may be salts of monovalent, divalent or trivalent metals.
  • the charge-enhancing additive useful herein may contain phenolate salts; or triazine phenol salts; or a triazine phenolate anion and a metal cation.
  • the charge-enhancing additive may be present in any suitable level as known in the art; or in an amount up to about 10%; or from about 0.02% to about 5%, by weight of the polymer component.
  • Fillers useful herein are typically particulate materials added into the polymer component to provide bulk and to reduce the overall material cost and are extruded together.
  • the particles are typically from about 0.5 ⁇ to 5 ⁇ in diameter, although they may not have a regular shape.
  • Non-limiting examples of fillers useful herein include inorganic fillers such as calcium carbonate, titanium dioxide, talc, barium carbonate, magnesium carbonate, magnesium sulfate, mica, clays, kaolin, diatomaceous earth, and the like.
  • Organic fillers include chitin, carbon black, wood and cellulose powders, etc.
  • a pigment whether liquid, solid, etc., may be added to any of the fibers herein to provide a color to the fiber.
  • the filter material's MERV (Minimum Efficiency Reporting Values) rating will very likely increase, indicating that the filter is better at removing particulates, especially charged particulates. See, for example, https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating-1, hereby incorporated by reference in its entirety, which explains MERV ratings and that it is derived from the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) [see www.ashrae.org].
  • ASHRAE American Society of Heating, Refrigerating, and Air Conditioning Engineers
  • the splittable fiber, the split fiber, the multicomponent fiber, the multicomponent staple fiber, and/or the nonwoven fabric is formed into a filter, such as an air filter for removing particulates from the air; or a face mask; or a HEPA filter; or a filter having a MERV rating of at least 8; or a filter having a MERV rating of at least 10; or a filter having a MERV rating of at least 14; or a filter having a MERV rating to at least 16.
  • a filter such as an air filter for removing particulates from the air; or a face mask; or a HEPA filter; or a filter having a MERV rating of at least 8; or a filter having a MERV rating of at least 10; or a filter having a MERV rating of at least 14; or a filter having a MERV rating to at least 16.
  • the splittable fiber, the split fiber, the multicomponent fiber, the multicomponent staple fiber, and/or the nonwoven fabric is formed into a filter; or an air filter; or a vehicle air filter; or an automotive engine air filter, an automotive cabin air filter, an HVAC air filter, a face mask/respirator filter; and a combination thereof; or a cigarette filter.
  • the splittable fiber, the split fiber, the multicomponent fiber, the multicomponent staple fiber, and/or the nonwoven fabric is formed into an insulator; or a heat insulator; or a sound insulator; or a thermal insulator.
  • the splittable fiber, the split fiber, the multicomponent staple fiber, and/or the multicomponent fiber is included or formed into a spun yarn. In an embodiment herein, the splittable fiber, the split fiber, the multicomponent fiber, the multicomponent staple fiber, and/or the nonwoven fabric is included in a wipe.
  • the TSI 8130A automated filter tester (see: https://www.tsi.com/products/filter-testers/automated-filter-tester-8130a/ by TSI Incorporated, Shoreview, Minnesota, USA) can be used to test the filtration efficiency herein.
  • the TSI 8130A creates 0.3 ⁇ particles which are injected into an airstream and passed through a filter sample. See: https://youtu.be/HSngoNqKXvI, which shows how the filter tester works.
  • the 0.3 ⁇ particles are measured both upstream and downstream of the filter sample. As charge (or lack thereof) greatly impacts such small particles, it this device and the associated test can easily show whether the filter sample has an electret charge and/or show its efficiency as measured in % penetration.
  • the % penetration is calculated as: (downstream particle concentration) / (upstream particle concentration) ⁇ 100.
  • a high % penetration indicates low filtration efficiency - i.e., many particles are passing through the filter. Conversely, a low % penetration indicates a high filtration efficiency where many particles are caught and held by the filter. As the particles build up on the filter sample, the filter tester continuously monitors the flow rate and the resulting pressure drop across the filter.
  • TOPAS Flat Sheet Filter Media Test System (Model # AFC132; "TOPAS”) quickly tests small discs of filter media according to the ASHRAE Standard 52.2-2017, hereby incorporated by reference in its entirety.
  • TOPAS has proprietary software that creates potassium chloride particles from 0.3 microns to 10.0 microns in diameter.
  • the horizontal duct holds the sample and challenges the media per the ASHRAE Standard 52.2-2017 at the filter design velocity (Residential furnace filters are 110 fpm).
  • Upstream and downstream particle counters determine the size and number of particles which are trapped and pass through the media giving each particle range (E1 0.3 - 1 micron, E2 1.0 - 3 micron, E3 3.0 - 10 micron) and correlating the efficiency in each group with the ASHRAE Standard 52.2 MERV rating chart.
  • the SIMCO-ION Electrostatic Fieldmeter (specifically model # FMX-003) is a commercially-available (see: https://www.simco-ion.com/) fieldmeter which measures the static charge of a material such as a fiber, a nonwoven fabric, etc.
  • the split distribution of the splittable fiber is determined with a Braunauer-Emmett-Teller (BET) test (see, for example, https://en.wikipedia.org/wiki/BET_theory) according to ISO 9277:2010 "Determination of the specific surface area of solids by gas absorption - BET method" (see, https://www.iso.org/standard/44941.html), hereby incorporated by reference in its entirety.
  • BET Braunauer-Emmett-Teller
  • the BET test measures the physical absorption of gas molecules onto the fiber (or sub-fiber) surface and therefore an increase in the BET test indicates an increase in surface area which corresponds to a higher split distribution/more splitting of the splittable fiber into sub-fibers as compared to a sample which does not contain split fibers.
  • the BET test only measures the total surface area (increase) and does not specifically distinguish between, for example, a single fiber which is split entirely into sub-fibers, and a plurality of fibers that are split only once to give the same total surface area.
  • the splittable fiber; or the multicompoenent splittable fiber; or the multicomponent splittable staple fiber; or the nonwoven fabric, herein possess a surface area after splitting; or after carding, of from about 115% to about 800%; or from about 125% to about 700%; or from about 135% to about 650%; or from about 150% to about 600% of the surface area of a comparable sample; or of substantially the same sample, before splitting; or carding.
  • the splittable fiber constitutes about 50% of the total fiber mass
  • the splittable fiber; or the multicompoenent splittable fiber; or the multicomponent splittable staple fiber; or the nonwoven fabric, herein possess a surface area after splitting; or after carding, of from about 115% to about 400%; or from about 125% to about 350%; or from about 135% to about 325%; or from about 150% to about 300% of the surface area of a comparable sample; or of substantially the same sample, before splitting; or carding.
  • the split distribution of the splittable fiber is determined with a Micronaire test (MIC) which is a Cotton industry standard measurement of a sample's air permeability and is used as an indication of fiber fineness and maturity (see, https://barnhardtcotton.net/blog/what-is-a-micronaire-in-cotton-and-why-does-it-matter/ and also https://www.cotton.org/journal/2005-09/2/upload/jcs09-081.pdf), all hereby incorporated by reference in their entireties.
  • MIC Micronaire test
  • the MIC may be measured via, for example, the Uster ® HVI 1000 (https://www.uster.com/en/instruments/cotton-classing/uster-hvi-2/), available from Uster Technologies AG, Sonnenbergstrasse 10, CH-8610 Uster, Switzerland.
  • Uster ® HVI 1000 https://www.uster.com/en/instruments/cotton-classing/uster-hvi-2/
  • the sample containing split fibers should have a higher air resistance.
  • measuring the MIC before and after splitting would indicate whether or not the splittable fiber(s) have actually split, and provide an indication of the split distribution.
  • the scaling of a Micronaire instrument is by gauging known fiber sizes over a range of 0.2 denier (100% opened fibers) to 3 denier (100% un-opened fibers).
  • the scale is accentually aligned with known fiber sizes across the expected range of opening to determine a 0% - 100% scale. Once the scale is established, then a nonwoven fabric sample containing splittable fibers having an original known denier can be tested both before and after splitting to determine the split distribution.
  • the split distribution of the splittable fiber is determined via visual and/or computer analysis of, for example, one or more scanning electron micrographs (SEMs).
  • SEMs scanning electron micrographs
  • identical; or substantially identical, samples may be compared before and after the splitting step (for example, by carding), to determine the split distribution.
  • the split distribution is characterized by analyzing scanning electron micrographs (SEMs) to estimate and/or calculate the split distribution.
  • SEMs may also be used herein to estimate/calculate the increase in surface area after splitting; or carding. It is recognized herein that counting microfibers and sub-fibers in a SEM image has one advantage over counting them in a cross section image, in that there is no ambiguity introduced by splitting that might occur in cutting the fiber for the cross section image.
  • the cross section image also has an advantage over the SEM, which is that in the cross section image there is no uncertainty whether a microfiber comprises one, two, or three segments, or 7, 8, or 9 segments, etc.
  • Control media is formed from 100% 3 dpf (denier per fiber) fibers.
  • Splittable fibers according to the invention of the same (initial) size are formed into a nonwoven web and then split into a nonwoven fabric containing split fibers. This nonwoven fabric is formed into a comparable filter, and then charged and left uncharged. All three structures are the same.
  • the MERV test is conducted according to ASHRAE MERV Standard 52.2-2017 and the data recorded below.
  • the uncharged split fiber sample increases in efficiency for E1, E2 and E3 as compared to the control sample.
  • the charged split fiber sample increases in efficiency E1, E2, and E3 with respect to both the control sample and the uncharged split fiber sample.
  • the control sample achieves a rating of MERV 8
  • the uncharged split fiber sample achieves a rating of MERV 10
  • the charged split fiber sample achieves a rating of MERV 12.
  • the lower CFM of the split fiber samples also indicates an increased surface area compared to the control due to fibers due to the splitting.
  • Nano fiber-based media are typically fibers less than 200 nano meters (nm) in diameter and are not typically charged. The pure physical filtration (through sieving) does not allow for depth filtration and larger particles can build up on the surface of the media causing premature high resistance. Nano fiber-based filtration media are also to be used for a typical residential furnace filter. Below is an internal flat sheet test of such media compared to the invention which uses depth filtration, physical filtration and electro statics to balance the filtration media allowing adequate filtration.
  • the present invention provides similar measurements as the Next Nano sheet; however, in a different technical manner.
  • nonwoven fabric samples with various split distributions are compared.
  • Control Sample is a nonwoven fabric containing 100% nonsplittable fibers (3 dpf) is measured by the BET test, and compared to Samples 1-3. The Control Sample is not carded.
  • Sample 1 contains, by weight, 50% nonsplittable fibers and 50% splittable fibers. Both the splittable fibers and the nonsplittable fibers are initially of the same denier (3 dpf) as the control sample and thus the fabric sample (prior to splitting) is essentially identical to the Control Sample. Sample 1 is then "slightly" carded in order to split the splittable fibers into sub-fibers.
  • Sample 2 is essentially identical to Sample 1, except that Sample 2 is "normally" carded to split the splittable fibers into sub-fibers.
  • Sample 3 is essentially identical to Sample 2, except that Sample 3 contains a charge-enhancing additive is added to the splittable fiber and Sample 3 is charged via Corona Charging. Without intending to be limited by theory it is believed that the significant increase in surface area between Sample 3 and Sample 2 is due to the charged fibers repelling each other and thereby increasing the overall surface area.
  • a conventional charge is applied to the formed nonwoven fabric after a thermal bonding process.
  • the charge polarity is negative 30Kv @ 2.5 mA but can range from 0.5 KV @ 1 mA to 50Kv @ 3.0 mA.
  • a SIMCO-ION FMX-003 Electrostatic Fieldmeter is used to measure the charge after the formation to the nonwoven fabric and before electret charging. The same electrostatic fieldmeter is used to measure the charge after electret charging and the results are shown below. Sample Charge (in kV) Nonwoven fabric before charging 0.0 Nonwoven web after charging -7.7 kV
  • Charge retention is a function of applied voltage, dwell time under the applicator bar (i.e., line speed in a continuous process), fiber density (surface area and basis weight), base fiber polymer, charge-enhancing additives and atmospheric conditions.

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  • Nonwoven Fabrics (AREA)
  • Filtering Materials (AREA)
  • Multicomponent Fibers (AREA)
EP21212071.1A 2020-12-02 2021-12-02 Fibre chargeable séparable, fibre multicomposant séparée, fibre à composants multiples séparée avec une charge durable, tissu non tissé, filtre et fil contenant cette fibre, et procédés de fabrication correspondants Withdrawn EP4144901A3 (fr)

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US202063120720P 2020-12-02 2020-12-02

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EP4144901A2 true EP4144901A2 (fr) 2023-03-08
EP4144901A3 EP4144901A3 (fr) 2023-04-05

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Country Status (4)

Country Link
US (1) US20220170201A1 (fr)
EP (1) EP4144901A3 (fr)
CA (1) CA3141239A1 (fr)
MX (1) MX2021014866A (fr)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5108820A (en) 1989-04-25 1992-04-28 Mitsui Petrochemical Industries, Ltd. Soft nonwoven fabric of filaments
US5336552A (en) 1992-08-26 1994-08-09 Kimberly-Clark Corporation Nonwoven fabric made with multicomponent polymeric strands including a blend of polyolefin and ethylene alkyl acrylate copolymer
JPH06254319A (ja) 1993-03-05 1994-09-13 Toyobo Co Ltd エレクトレットフィルター
EP0623941A2 (fr) 1993-03-09 1994-11-09 Hoechst Celanese Corporation Elektets en polymère ayant une stabilité de charge ameliorée
US5382400A (en) 1992-08-21 1995-01-17 Kimberly-Clark Corporation Nonwoven multicomponent polymeric fabric and method for making same
US20030203695A1 (en) 2002-04-30 2003-10-30 Polanco Braulio Arturo Splittable multicomponent fiber and fabrics therefrom
US20150343455A1 (en) 2012-12-28 2015-12-03 3M Innovative Properties Company Electret webs with charge-enhancing additives
US20160067717A1 (en) 2013-04-19 2016-03-10 3M Innovative Properties Company Electret webs with charge-enhancing additives
US20190336896A1 (en) 2017-01-05 2019-11-07 3M Innovative Properties Company Electret webs with charge-enhancing additives

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL279868A (fr) * 1963-07-15
US3917784A (en) * 1972-08-15 1975-11-04 Kanebo Ltd Method for producing pile fabrics having excellent appearance and properties
JPS54106691A (en) * 1978-02-01 1979-08-21 Toray Industries Multicomponent fiber
JP2954782B2 (ja) * 1992-05-26 1999-09-27 帝人株式会社 分割型複合繊維
DE19843000C2 (de) * 1998-09-21 2000-07-13 Freudenberg Carl Fa Luftfilter
JP4002036B2 (ja) * 1999-09-01 2007-10-31 株式会社クラレ 易分割性ポリアミド系複合繊維
US6444312B1 (en) * 1999-12-08 2002-09-03 Fiber Innovation Technology, Inc. Splittable multicomponent fibers containing a polyacrylonitrile polymer component
JP4411859B2 (ja) * 2003-04-22 2010-02-10 東レ株式会社 ポリエステル短繊維およびそれからなる中入れ綿、ポリエステル短繊維の製造方法
GB201712165D0 (en) * 2017-07-28 2017-09-13 Smith & Nephew Wound dressing and method of manufacture

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5108820A (en) 1989-04-25 1992-04-28 Mitsui Petrochemical Industries, Ltd. Soft nonwoven fabric of filaments
US5382400A (en) 1992-08-21 1995-01-17 Kimberly-Clark Corporation Nonwoven multicomponent polymeric fabric and method for making same
US5336552A (en) 1992-08-26 1994-08-09 Kimberly-Clark Corporation Nonwoven fabric made with multicomponent polymeric strands including a blend of polyolefin and ethylene alkyl acrylate copolymer
JPH06254319A (ja) 1993-03-05 1994-09-13 Toyobo Co Ltd エレクトレットフィルター
EP0623941A2 (fr) 1993-03-09 1994-11-09 Hoechst Celanese Corporation Elektets en polymère ayant une stabilité de charge ameliorée
US20030203695A1 (en) 2002-04-30 2003-10-30 Polanco Braulio Arturo Splittable multicomponent fiber and fabrics therefrom
US20150343455A1 (en) 2012-12-28 2015-12-03 3M Innovative Properties Company Electret webs with charge-enhancing additives
US20160067717A1 (en) 2013-04-19 2016-03-10 3M Innovative Properties Company Electret webs with charge-enhancing additives
US20190336896A1 (en) 2017-01-05 2019-11-07 3M Innovative Properties Company Electret webs with charge-enhancing additives

Also Published As

Publication number Publication date
US20220170201A1 (en) 2022-06-02
EP4144901A3 (fr) 2023-04-05
CA3141239A1 (fr) 2022-06-02
MX2021014866A (es) 2022-06-03

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