WO2024013645A1 - Etoffe non tissée et procédé pour sa fabrication - Google Patents

Etoffe non tissée et procédé pour sa fabrication Download PDF

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Publication number
WO2024013645A1
WO2024013645A1 PCT/IB2023/057074 IB2023057074W WO2024013645A1 WO 2024013645 A1 WO2024013645 A1 WO 2024013645A1 IB 2023057074 W IB2023057074 W IB 2023057074W WO 2024013645 A1 WO2024013645 A1 WO 2024013645A1
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WO
WIPO (PCT)
Prior art keywords
nonwoven fabric
fabric
fibers
wet
web
Prior art date
Application number
PCT/IB2023/057074
Other languages
English (en)
Inventor
Balázs TOLNAI
Guy Njamen Tchapda
Original Assignee
Kruger Inc.
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Filing date
Publication date
Application filed by Kruger Inc. filed Critical Kruger Inc.
Publication of WO2024013645A1 publication Critical patent/WO2024013645A1/fr

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Classifications

    • 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
    • D04H1/425—Cellulose series
    • 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
    • D04H1/425—Cellulose series
    • D04H1/4258—Regenerated cellulose series
    • 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
    • D04H1/44—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 the fleeces or layers being consolidated by mechanical means, e.g. by rolling
    • D04H1/46—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 the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres
    • D04H1/492—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 the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres by fluid jet
    • 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
    • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
    • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
    • D04H1/732—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by fluid current, e.g. air-lay
    • 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
    • D04H5/00—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length
    • D04H5/02—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length strengthened or consolidated by mechanical methods, e.g. needling
    • D04H5/03—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length strengthened or consolidated by mechanical methods, e.g. needling by fluid jet
    • 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
    • D04H5/00—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length
    • D04H5/08—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length characterised by the method of forming fleeces or layers, e.g. reorientation of fibres or yarns

Definitions

  • the invention relates to nonwoven fabric, and more particularly, although not exclusively, to systems of nonwoven sheet fabrics comprising cellulose filaments and methods of fabrication thereof.
  • Nonwoven fabrics are used in numerous applications, such as in the medical field, household industry, geotextile industry, food industry, personal care field and the like. In most applications, the nonwoven fabrics are designed to meet end-use performance criteria, and so, in dry or wet state. In some instances, the fabrics are designed to be disposable such as being dispersible, recyclable, degradable and/or biodegradable.
  • Hydrophilicity is required for wet wipe applications in order to absorb and retain the wiping solution within the nonwoven fabric. Aside from incorporating naturally hydrophilic materials in the fabric, hydrophilicity is also achieved by surfactant treatment. However, these surfactants are often synthetic chemicals and/or cause a risk of skin irritation.
  • state-of-the-art nonwoven fabric often relies on chemical additives, thermoplastics and other non-biodegradable, non-ecofriendly and plastic-based materials. Therefore, such fabrics suffer from a drawback and improvements remain important.
  • This invention relates to a nonwoven fabric made of short cellulose fibers such as wood pulp with a fiber length of approximately 2 mm to 5 mm and cellulose filaments (“CF”), which are a refined fiber with a high aspect ratio.
  • CF cellulose filaments
  • a nonwoven fabric comprising short fibers having a length of about between 2 mm and 5 mm, and cellulose filaments (CF) being present at a proportion of up to 10 wt-% of the nonwoven fabric, such that the cellulose filaments help bind the short fibers in the nonwoven fabric giving it advantageous physical properties.
  • CF cellulose filaments
  • the nonwoven fabric comprises long fibers having a length of more than 5 mm, the long fibers being present at a proportion of up to about 40 wt-% of the nonwoven fabric, such that the cellulose filaments help bind the long fibers in the nonwoven fabric.
  • the proportion of cellulose filaments is between about 2 wt-% and 7 wt-%.
  • the proportion of long fibers is up to about 20 wt-%.
  • the proportion of long fibers is between about 20 wt-% and 40 wt-%.
  • the long fibers are selected from the group consisting of man-made fibers regenerated cellulose and a mixture thereof.
  • the long fibers are selected from the group consisting of regenerated cellulose fibers, hemp, cotton, hemp, jute, flax and a mixture thereof.
  • the short fibers are derived from a raw material selected from the group consisting of wood pulp, hemp, bamboo, bagasse, flax, natural plant fibers, cotton and a mixture thereof.
  • the nonwoven fabric is a wet wipe.
  • the wet wipe is in a liquid phase comprising alcohol.
  • the liquid phase has an alcohol content between 20 vol% and 80 vol%, preferably about 60 vol%.
  • the nonwoven fabric may be in a medium comprising a lotion.
  • the lotion comprises a water-based lotion.
  • the nonwoven fabric has a basis weight of about between about 40 GSM to 85 GSM.
  • the nonwoven fabric has a dry tensile strength (MD and CD) of at least about 31 N/50mm and a wet tensile strength (MD and CD) of at least about 6.4 N/50mm.
  • the nonwoven fabric has a dry maximal elongation of at least about 7% and a wet maximal elongation of at least about 26%.
  • the nonwoven fabric has an alcohol absorptive capacity of at least about 4.2 g/g.
  • the nonwoven fabric has a water absorptive capacity of at least about 6.8 g/g.
  • the nonwoven fabric has a liquid wicking rate of at least about 43 mm/30sec.
  • the nonwoven fabric has a slosh box disintegration rate of at least about 60% as measured according to IWSFG Slosh Box standards.
  • the nonwoven fabric has an opacity of at least about 50%.
  • the nonwoven fabric has a dry linting rate of about 0.01 % and a degradation rate of about 2.14%.
  • a method for fabricating a nonwoven fabric comprising: a) preparing a liquid suspension of i) short fibers having a length of about between 2 mm and 5 mm; and ii) cellulose filaments being present at a proportion of up to 10 wt-% of the dry nonwoven fabric; b) forming a web from the prepared liquid suspension and dewatering it; c) hydroentangling the web to obtain a wet fabric; and d) drying the wet fabric.
  • the liquid suspension comprises long fibers having a length of more than about 5 mm, the long fibers being present at a proportion of up to about 40 wt-% of the nonwoven fabric.
  • said forming the web comprises wetlaying the liquid suspension.
  • the method comprises patterning the wet fabric.
  • the method comprises drying the wet fabric.
  • the method comprises calendering the dried fabric.
  • the method comprises embossing the dried fabric.
  • the method comprises winding the dried fabric thereby obtaining a roll of fabric.
  • a pulp and paper product comprising short fibers having a length of about between 2 mm and 5 mm and cellulose filaments being present at a proportion of up to 10 wt-% of the nonwoven fabric, such that the cellulose filaments bind the short fibers in the nonwoven fabric.
  • a method for producing a nonwoven fabric comprising providing a liquid suspension of never-dry pulp, forming a web from the provided liquid suspension and dewatering the web, entangling the web to obtain a wet fabric and drying the wet fabric.
  • the liquid suspension comprises cellulose filaments.
  • the liquid suspension comprises long fibers.
  • the long fibers have a length of at least 5mm.
  • the long fibers are present at a proportion of up to 40 wt-% of the nonwoven fabric.
  • the cellulose filaments are present at a proportion of up to 10 wt-% of the nonwoven fabric.
  • the never-dry pulp comprises short fibers having a length between about 2 mm and about 5 mm.
  • the forming the web comprises wet-laying the liquid suspension.
  • the never-dry pulp is derived from a raw material selected from the group consisting of wood, hemp, bamboo, bagasse, flax, natural plant fibers, cotton and mixtures thereof.
  • the fabric has a machine-direction dry tensile strength of at least 45 N/50mm and a machine-direction wet tensile strength of at least 9 N/50mm.
  • the fabric has a cross-machine-direction dry tensile strength of at least 25 N/50mm and a cross-machine-direction wet tensile strength of at least 6 N/50mm.
  • the fabric is flushable. In embodiments, the fabric is IWSFG Slosh Box flushable.
  • One advantage is that the present invention provides a product with performant structural properties while being easily flushable.
  • the present invention provides a product that may be essentially conceived using wood pulp and mechanically obtained product thereof.
  • Another advantage is that the present invention reduces the amount of lint and dust in the manufacturing process, which greatly reduces risk of unwanted fires, air contamination and other accidents.
  • Yet another advantage is that a product according to the present invention has improved structural properties while reducing the need for man-made fibers, binders or combinations thereof.
  • a presence of up to 10% of cellulose filaments in the nonwoven fabric allows to reduce the presence of long fibers to less than about 40% while keeping the strength properties of the resulting fabric.
  • Figure 1 represents an electron microscope image of the fiber structure of a nonwoven fabric according to one embodiment of the invention
  • Figure 2 represents an electron microscope image of the fiber structure of a nonwoven fabric comprising cellulose filaments according to one embodiment of the invention
  • Figure 3 represents a schematic view of a system for fabricating a nonwoven fabric according to one embodiment of the invention.
  • Figure 4 represents a flowchart that illustrates a method for fabricating a nonwoven fabric according to one embodiment of the invention.
  • Figure 5 represents a method of producing a nonwoven fabric according to one embodiment.
  • Figure 6 represents the characteristic strengths of nonwoven fabric samples according to an embodiment.
  • Figure 7 represents the characteristic strains of nonwoven fabric samples according to an embodiment.
  • Figure 8 represents the Weibull fit of nonwoven fabric samples according to an embodiment.
  • Figure 9 represents the Weibull modulus of nonwoven fabric samples according to an embodiment
  • Figures 10A and 10B represent the tensile strengths of nonwoven fabric samples comprising never-dry and market pulp according to an embodiment.
  • Figures 11A and 11 B represent the tensile strengths of nonwoven fabric samples comprising 0% and 5% CF according to an embodiment.
  • Figures 12A and 12B represent dry linting and dusting test results on samples of nonwoven fabrics according to an embodiment.
  • Figure 13 represents dry linting and dusting test results on samples of nonwoven fabrics according to an embodiment.
  • Figure 14 represents wet linting and dusting test results on samples of nonwoven fabrics according to an embodiment.
  • Figures 15A, 15B, 15C and 15D represents dry and wet linting results on samples of nonwoven fabrics comprising 0% CF and 5% CF according to an embodiment.
  • Figures 16A and 16B provide a magnified view of portions of Figures 15A and 15B respectively.
  • Figure 17 represents exemplary degraded nonwoven fabric samples according to an embodiment and corresponding degradation scores.
  • Figure 18 represents dry degradation test results on samples of nonwoven fabric according to an embodiment.
  • MD machine-direction
  • CD cross-machine direction
  • wet-laying or “wet-laid” refer to a method for depositing a liquid suspension to form a web.
  • never-dried pulp refers to pulp that has not been dried prior to use, and processes comprising the same.
  • market pulp and “dry-lap” refer to conventional pulp that has been dried prior to use, and processes comprising the same.
  • hydroentangling or “hydroentanglement” refer to a method for intertwining fiber in a web using waterjets.
  • hydroembossing refers a method of patterning a surface by spraying waters jets on sheet in contact with a patterned drum.
  • biodegradable refers to a composition of matter is capable of being decomposed by bacteria or other living organisms within a reasonable period.
  • plastic-free refers to a composition of matter that contains essentially no amount of synthetic polymer(s) or any other non-naturally occurring polymer, but may contain cellulose-based fiber and/or regenerated cellulose, for example viscose, rayon, acetate, triacetate, modal, Tencel, and Lyocell.
  • long fiber and “long cellulose fiber” refers to fiber whose composition, structure and properties were significantly modified in a given process. Generally, “long fiber” and “long cellulose fiber” do not contain synthetic plastic fiber and cellulose filament and have a length of more than 5 mm.
  • short fiber and short cellulose fiber refer to fibers composed of a polymer matrix, typically glucose, that is derived from a plant-based material through mechanical and/or chemical process. Generally, “short fiber” and “short cellulose fiber” have a length of between 2 mm and 5 mm.
  • cellulose filaments when used herein relates to plant based fibers treated to achieve a high aspect ratio of fibers in comparison to untreated fibers. It will be appreciated that the “cellulose filaments” referred to herein may relate for example, to Filocell (R) from Kruger Inc.
  • fabric when used herein relates to any web like material that can be rolled or can be cut to specific sizes.
  • dewatering when used herein relates to processes, steps and methods for removing at least a portion of water contained in a material, for example a web of fibers, thereby obtaining a product having a lower water content. It will be understood that while drying may be a subset of dewatering, dewatering may use methods and/or equipment not used for drying materials as conventionally understood.
  • FIG. 1 there is depicted an electron microscope image of the fiber structure of a nonwoven fabric.
  • the image was recorded using backscattered electrons with an initial electrical potential of 10.0 kV, and the image has an enhancement of x500.
  • the nonwoven fabric depicted in Figure 1 is composed of short fibers 10 obtained from Northern Bleached Softwood Kraft (NBSK) pulp and 1.4 dtex 10 mm Lyocell long fibers 20, in an 80%/20% proportion.
  • NBSK Northern Bleached Softwood Kraft
  • Short fibers 10 are typically obtained by mechanically or chemically separating cellulose fibers of a plant-based material such as wood. Wood pulp is composed of short fibers 10 that have irregular shapes and that have a length of about 2 mm to 5 mm, and a width and thickness in the 10 microns to 100 microns range. In some embodiments, the short fibers 10 have a rectangular-like cross-section shape. However, the size and shape of the short fibers 10 greatly vary according to the embodiment.
  • plastic free long fibers 20 are obtained by processing cellulose fiber using mechanical and/or chemical processes. For instance, Viscose, which is a long fiber obtained by dissolving pulp and then reconstituting it by dry jet-wet spinning, is used massively worldwide as long fibers 20 in various products. The person skilled in the art understands that long fibers 20 may be commonly referred to as polymers.
  • the long fibers 20 used in the present technology typically have a cylindrical shape having a length between 5 and 14 mm and a radius of tens of microns.
  • long fibers 20 may be generally uniform.
  • short fibers 10 are intertwined with long fibers 20 on a microscopic scale, which suggests a mechanical cohesion between the material composing the nonwoven fabric.
  • FIG. 2 there is depicted an electron microscope image of the fiber structure of a nonwoven fabric comprising cellulose filaments (CF).
  • the image was recorded using backscattered electrons with an initial electrical potential of 10.0 kV, and the image has an enhancement of x500.
  • the nonwoven fabric depicted in Figure 2 is composed of short fiber 10 obtained from NBSK pulp, long fiber 20 and CF 30, in an 80%/15%/5% proportion.
  • CF 30 is an engineered technological material first described in United States Patent Application Publication No. US 2011/0277947 A1 (Hua et al.), published on November 17, 201 1 , entitled “Cellulose Nanofilaments and Method to Produce Same”.
  • CF 30 is obtained by mechanically breaking down wood pulp into thin and long polymer chains in a mechanical, chemical free, zero waste process which produces long and thin high aspect ratio filaments in the form of moist or dry fluff ready to be used.
  • CF 30 provides unique intrinsic properties and characteristics. More precisely, CF 30 has an average diameter of 30 nm to 500 nm, and an average length of about 200 microns to 2 mm, which results with a much higher aspect ratio than other types of microscopic cellulose-derived products.
  • the nonwoven fabric depicted in Figure 2 is composed of 5% CF 30 and has a denser structure than the one depicted in Figure 1 .
  • CF 30 forms links in the short fibers 10 and Lyocell long fibers 20 matrix.
  • the CF 30 may solidify and strengthen the short fibers 10 and long fibers 20 matrix by acting as a binding agent therein, by providing more entanglement points.
  • the bonding induced by CF 30 may be related to covalent bonding.
  • the CF 30 is characterized by a high relative bonding area.
  • the nonwoven fabric has a proportion of CF 30 up to about 10%.
  • the nonwoven fabric has a proportion of long fibers 20 up to 20%, such as in low-strength products.
  • the long fibers 20 are selected from the group consisting of manmade fibers, regenerated cellulose and a mixture thereof.
  • the long fibers 20 are selected from the group consisting of lyocell fibers, viscose fibers, cotton, hemp, jute, flax and a mixture thereof.
  • the short fibers 10 are derived from a raw material selected from the group consisting of wood pulp, hemp, bamboo, bagasse, flax, natural plant fibers, cotton, and a mixture thereof.
  • the nonwoven fabric is contained in a medium having an alcohol content of about 60% in the liquid phase.
  • IPA isopropanol
  • the medium may comprise a lotion, for example a water-based lotion. Other mediums will be apparent to a skilled person.
  • the basis weight of the fabric may greatly vary according to the product and may vary from about 10 GSM (gram by square meter) to 500 GSM, preferably from 40 GSM to 85 GSM.
  • the nonwoven fabric of the present disclosure provides a synergistic effect whereby OF may replace at least a portion of man-made fibres, for example long fibres 20, in a nonwoven while providing similar or improved strength. Accordingly, the nonwoven fabric of the present disclosure may be flushable and eco-friendly without impairing product quality.
  • FIG. 3 there is depicted a schematic view of a system 100 for fabricating a nonwoven fabric.
  • the system 100 generally comprises a wet-laying unit 110 that forms a web from a liquid suspension, a patterning unit 120 that binds the web into a fabric, a dewatering unit 130 that removes the majority of the water in the fabric, a drying unit 140 that removes any water left in the fabric, a calendering unit 150 that smooths the fabric, a sensing unit 160 that monitors the output or resulting fabric and a winding unit 170 that produces rolls of fabrics.
  • a wet-laying unit 110 that forms a web from a liquid suspension
  • a patterning unit 120 that binds the web into a fabric
  • a dewatering unit 130 that removes the majority of the water in the fabric
  • a drying unit 140 that removes any water left in the fabric
  • a calendering unit 150 that smooths the fabric
  • sensing unit 160 that monitors the output or resulting fabric
  • a winding unit 170 that produces rolls of fabrics.
  • the feedstock entering the system 100 may be a liquid suspension comprising wood pulp, which comprises short fibers 10, long fibers 20 and OF 30.
  • the liquid suspension typically has a consistency between 0.01 and 0.05%
  • the liquid used to form the suspension typically is water.
  • Other liquids and/or components may be present and will be apparent to the skilled person.
  • the fibers in suspension are deposited on a porous surface to separate the fibers from the fluid to form a web.
  • the mesh-like porous surface is mounted on a conveyor belt having a defined speed that exits the wet-laying unit 110 with the deposited web.
  • the person skilled in the art understands that the speed of the conveyor belt and the flow rate of the liquid suspension affects the thickness and the density of the deposited web.
  • the output of the wet-laying unit is a web.
  • the patterning unit 120 is configured to receive the deposited web and form a fabric therewith. It will be appreciated that the patterning unit 120 may bind the web by various means and processes. For instance, the patterning unit 120 may use a bonding method selected from the group consisting of thermal bonding, hydroentangling, ultrasonic pattern bonding, embossing, needle punching, chemical bonding, and the like. While the present technology is not limited to a particular bonding method, a preferred embodiment is presented and detailed below.
  • the patterning unit 120 comprises a hydroentanglement unit.
  • a hydroentanglement unit comprises a series of water jets projecting pressurized water onto the web, thereby causing the fiber content to intertwine and to bind together.
  • An advantage of the hydroentanglement method is that it creates a highly intertwined pattern without using chemical additives or high temperatures.
  • the fibrous web goes through the patterning unit 120 in a defined direction, thereby creating a patterned fabric that is bound.
  • the person skilled in the art understands that different patterns impact MD and CD properties in different ways.
  • the dewatering unit 130 and/or the drying unit 140 is configured to receive the bound fabric outputted by the patterning unit 120, the bound fabric generally containing water.
  • the fabric may be dewatered by stretching the fabric in the MD and/or CD direction, by blowing heated or non-heated air or other gas onto the fabric and by any other methods promoting the migration of water outside of the fabric.
  • the dewatering unit 130 comprises a through air drying (TAD) unit, which is a type of unit well known by the person skilled in the art.
  • TAD through air drying
  • the dewatering unit is a suction box dewatering unit, or a vacuum box dewatering unit. Other acceptable dewatering means and/or units will be apparent to a skilled person.
  • the output of the dewatering unit 130 is a dewatered fabric. It will be appreciated that the dewatering unit 130 may be present before and/or after the patterning unit 120, in accordance with the embodiment.
  • the drying unit 140 is configured to receive the dewatered fabric outputted from the dewatering unit 130. During the dewatering step, most of the water used in subsequent steps that is absorbed by the fabric is removed therefrom. However, the fabric typically remains moist when exiting the dewatering unit 130 and generally needs to be further dried before entering the calendering unit 150.
  • the drying unit 140 comprises lamps that project radiation onto the surface of the dewatered fabric thereby heating its content. The heat created by the incoming radiation evaporates the remaining water in the fabric.
  • the output of the drying unit 140 is an essentially dried fabric.
  • the drying unit 140 comprises infrared (IR) lamps.
  • the dewatering unit 130, the drying unit 140 and/or the calendering unit 150 may be optional in some embodiments of the system 100.
  • the person skilled in the art also understands that it is preferable that the system 100 includes at least one of the dewatering unit 130 and the drying unit 140 when the patterning unit 120 comprises an hydroentanglement unit and when using a wet-laying unit 110.
  • patterning unit 120, the dewatering unit 130 and the drying unit 140 may be combined and/or interchanged with one another, according to the embodiment.
  • the calendering unit 150 is configured to receive the essentially dried fabric from the drying unit 140. Generally, the calendering unit 150 comprises a series of rolls that compress the fabric to create a smooth finish and/or patterns and designs on the surface. It will be appreciated that the calendering unit 150 may treat the fabric by various means and processes. For instance, the calendering unit 150 may use a calendering method selected from the group consisting of beetling, watering, embossing, Schreiner embossing, and the like. In one embodiment, the output of the calendering unit 150 is a calendered fabric.
  • the series of rolls comprised in the calendering unit 150 are heated.
  • the system 100 further comprises an embossing unit.
  • An embossing unit typically comprises a roll having a patterned surface that applies pressure on a fibrous web, thus reproducing the pattern in the web.
  • the system 100 comprises a hydroembossing unit, which applies pressure using water jets on the fabric that is in contact with a patterned drum. It will be appreciated that hydroembossing is typically done without heating the fabric.
  • the sensing unit 160 is configured to receive the calendered and/or embossed fabric.
  • the sensing unit 160 generally comprises humidity sensors, weight scales, spectrometers, opacity sensors and other means of monitoring the fabric. It will be appreciated that the measurement means comprised in the sensing unit 160 vary according to the embodiment.
  • the output of the sensing unit 160 is typically the same as its input, i.e., the calendered and/or embossed fabric. Therefore, the person skilled in the art understands that the sensing unit 160 may be optional in some embodiments, as it mainly serves to monitor and control the produced fabric.
  • the sensing unit 160 control the process parameters of the subsequent units according to the measurements made on the calendered and/or embossed fabric. For instance, the sensing unit 160 may control the flow rate of the liquid suspension in the wet-laying unit 110, may control the pressure of the water and the number of water jets used in the patterning unit 120, may control the temperature and the flow rate of the air used in the dewatering unit 130, may control the electrical current provided to the lamp in the drying unit 140, may control the pressure or the heat of the rolls in the calendering unit 150 and the like.
  • the sensing unit 160 controls the speed of the conveyor belt used in the system 100.
  • the winding unit 170 is configured to receive the resulting fabric and for forming a roll of fabric.
  • the winding unit 170 is connected to an extremity of the continuous feed of fabric outputted by the calendering unit 150 or the sensing unit 160, and creates a force on the fabric so that the latter remains straight in the various units of the system 100. Once a sufficient amount of fabric is winded by the winding unit, the roll of fabric installed in the system 100 is removed therefrom and a new roll is installed.
  • FIG. 4 there is depicted a flowchart that illustrates a method for making a nonwoven fabric.
  • a suspension is prepared.
  • the suspension prepared comprises, but is not limited to, CF, long fibers and short fibers.
  • each component is mixed using a mixer until a sufficiently homogeneous distribution is obtained. Once the mixture is obtained, it is combined with water to obtain the desired consistency to thereby obtain the suspension.
  • the components are directly mixed with water.
  • the mixture in the context of air-laying for instance, is not combined with water.
  • a web is formed.
  • the formation of the web varies according to the embodiment.
  • the web is formed by wet-laying, or airlaying carding/crosslapping the suspension.
  • the suspension or the mixture is deposited on the surface of a conveyor belt thereby forming the web.
  • the fibers contained in the suspension or the mixture are aligned mechanically during processing step 210.
  • the alignment may be MD, CD or any other orientation, in accordance with the embodiment.
  • a fabric is obtained by binding the web.
  • the structure of the web formed at processing step 210 is mechanically and/or chemically bound so that it forms a uniform yet nonwoven fabric. It will be appreciated that the web may be bound using a dry process or a wet process, according to the embodiment.
  • the processing step 220 is processed by hydroentangling the web.
  • the fabric is dried. After being bound, the fabric generally contains a certain amount of water.
  • the processing step 230 comprises a TAD unit.
  • the fabric is dewatered before being dried.
  • processing step 240 the fabric is calendered.
  • the calendering process of processing step 240 is the last step that modify the structure of the fabric.
  • the fabric is pressed between rolls so that the surface is smoothed.
  • the processing step 240 is performed by beetling, watering or embossing the fabric.
  • the fabric properties are measured after being calendered.
  • the fabric is wound after being calendered or measured.
  • Figure 5 a process for producing a nonwoven fabric is presented. It has been unexpectedly discovered that using never-dry pulp, i.e. pulp that has not undergone conventional drying following its production and prior to its use in manufacturing, in the manufacture of nonwovens provides several advantageous effects.
  • the process comprises providing a never-dried pulp in a suspension (501).
  • the suspension may be a suspension of the pulp in water, in a solvent, or in mixtures thereof,
  • the suspension may have a liquid to solids ratio and other characteristics appropriate for the predetermined parameters of the nonwoven to be manufactured.
  • the suspension may comprise CF.
  • the suspension may comprise long fibers, for example man-made fibers, for example Tencel or Lyocell or Rayon or other suitable fibers, or for example long fibers as described above.
  • the suspension may then be processed by forming a web (502), for example a web of pulp fibers.
  • a web for example a web of pulp fibers.
  • the suspension may be dynamically mixed and the web may be formed in or by a wet-laying unit, for example by depositing the suspension onto a porous surface to separate liquids from solids.
  • the web may be formed by passing one or more porous sheets through the suspension, thereby depositing solids on one surface of the sheet and forming a web.
  • Other web-forming methods are possible.
  • the formed web may then be dewatered (503).
  • dewatering comprises the removal of at least some of the liquid or liquids present in the web formed at step 502.
  • dewatering may comprise removing at least 10% of the liquids contained in the formed web.
  • Dewatering may comprise removing up to 90%, or 95%, or 99% of the liquids contained in the formed web.
  • drying is a form of dewatering wherein the resulting product is substantially dry.
  • the dewatered web may comprise up to 95% water.
  • the dewatered web may comprise between 30% and 85% water, or between 40 and 75% water, or other levels of dewatering and/or drying. Dewatering levels appropriate for the predetermined characteristics and a predetermined use of the final nonwoven product will be apparent to the skilled person.
  • the formed web may then be entangled (504). It will be understood that several entangling methods may be suitable for the process 500. For example, the web may be hydroentangled. The web may be mechanically entangled, for example by felting, looming, needling and other acceptable methods.
  • the entangled web may then be further dewatered and/or dried (505).
  • the entangled web may be dried to form a substantially dry nonwoven, for example a fabric suitable for producing a wipe.
  • the entangled web may be partially dewatered whereby the entangled web maintains its structure under light or moderate strain, however maintains a high moisture and/or liquid content.
  • the entangled web may be partially dewatered to form a wet wipe.
  • the process 500 provides one or more advantages over conventional nonwoven manufacturing processes. For example, the process 500 provides improved opacity and improved bulk for a nonwoven product.
  • nonwovens produced using never-dried pulp show improved wet and dry tensile strength compared to nonwovens produced using market or dried pulp.
  • a further advantage provided by a nonwoven produced according to the process 500 comprises improved eco-friendliness.
  • the nonwoven provides improved tensile strengths whilst being plastic-free. Accordingly, such a flushed nonwoven may disperse releasing less plastics into the environment compared to a conventional nonwoven of comparable strength.
  • the process 500 may comprise providing additional components.
  • the suspension may comprise other components, for example colour additives, scent additives, cleaning additives, detergents, hydrating additives and other additives suitable for an intended use of the nonwoven.
  • nonwoven formed according to the process 500 may be suitable for making a variety of products, such as nonwoven fabrics, for example wet wipes, dry wipes and/or flushable wipes.
  • Table 2 Structural properties of nonwoven samples according to Table 1 .
  • CF addition significantly improved several characteristics of a nonwoven.
  • CF addition improved the tensile strength, while maintaining flushability.
  • CF addition improved the tensile strength and other characteristics of a nonwoven despite a reduction in overall long fiber content. For example, a 5% increase in CF content between samples 2 and 3 resulted in a marked tensile strength increase despite a 10% reduction in long fiber content. It will be apparent to a skilled person that a reduced long fibre content is advantageous at least for the reasons of reducing man-made fiber content in a flushable nonwoven and improving the nonwoven’s degradation properties once used and/or disposed of.
  • uniformity of the tensile strengths of a nonwoven product may be a desirable quality.
  • a nonwoven product exhibiting lower strength uniformity may provide pockets or areas of higher strength interspersed with lower-strength areas or pockets, leading to lower product strength overall, for example during use, for example during dispensing and use as a wipe.
  • Strength uniformity is related to the distribution of tensile strength, which follows a Weibull distribution according to the following equation wherein the term “m” denotes the Weibull modulus, also known as m-factor, an indicator of distribution uniformity:
  • samples B and E exhibit higher characteristic strengths overall.
  • the characteristic strength is the location of the center peak of the Weibull distribution. The higher the characteristic strength, the stronger the fabric is overall.
  • Samples B and E comprise CF, namely Filocell, while the other samples do not comprise CF. Accordingly, CF appears to markedly improve the characteristic strength of a nonwoven fabric.
  • the samples tested exhibit characteristic strains ranging between about 2% and about 7%.
  • the characteristic strain is the location of the center peak of the Weibull distribution. The higher the characteristic strain, the less stretch the nonwoven has overall. Accordingly, CF does not appear to significantly affect the characteristic strain of a nonwoven, thus maintaining stretch properties compared to conventional, non-CF comprising nonwovens.
  • the samples exhibit a high Weibull fit. Accordingly, the samples’ characteristics substantially align with a Weibull distribution and thus an m-factor analysis may provide relevant results.
  • samples B and E exhibit a markedly higher Weibull modulus than the remaining samples.
  • the Weibull modulus scale is logarithmic, and accordingly samples B and E perform impressively compared to the remaining samples.
  • the addition of CF, for example of Filocell, to a nonwoven fabric markedly increases the strength uniformity of a nonwoven. Improved strength uniformity is desirable, in particular for consumers, for example consumers of wet or dry wipes. A product exhibiting higher strength uniformity may be less susceptible to breaking, tearing or disintegrating suddenly and unexpectedly when exposed to stress or to strain during ordinary use.
  • Table 5 displays, in particular, the impact of using never-dry pulp while the source species remain substantially the same.
  • Table 5 displays, in particular, the impact of using never-dry pulp while the source species remain substantially the same.
  • the compositions of the nonwoven samples are summarized in Table 5.
  • the sample denoted NR6364 in two columns of Table 5 refers to the same sample and to the same tests performed on said sample.
  • the sample is described as “market pulp” for the purpose of distinguishing the sample from a nonwoven comprising never-dry pulp, and as CF(0) for the purpose of distinguishing the sample from a nonwoven comprising CF.
  • samples comprising never-dry pulp exhibit greater tensile strength both in MD and CD directions in both wet and dry states than samples comprising market pulp. Indeed, samples comprising never-dry pulp appear to exhibit approximately 25-50% greater strength than market pulp-comprising samples.
  • samples comprising CF show a marked improvement in dry tensile strengths in MD and CD directions compared to samples comprising market pulp. CF appears to affect wet tensile strength of a nonwoven differently. As shown in Figure 1 1 B, nonwoven samples comprising CF exhibited greater wet tensile strength in the MD patterning direction, however exhibited a lower wet strength in the CD direction.
  • Table 6 presents the compositions of nonwoven samples for the purpose of the dry lint test.
  • a dry lint test may comprise rubbing a nonwoven sample on a surface which may cause friction or resistance, for example on black felt.
  • lint refers to bundles built up of many fibers
  • dust refers to individual fibers removed by rubbing onto the black felt
  • Figure 12A shows significant lint production by a sample, corresponding to a higher lint %.
  • Figure 12B shows the dry lint test result of a sample exhibiting substantially no linting.
  • nonwoven samples comprising both a 60/40 and an 80/20 pulp to man-made fibre proportion exhibited lint and dust production.
  • samples comprising a lower proportion of man-made fibres, but no CF exhibited on average substantial lint production.
  • samples comprising CF exhibited substantially no average lint production. Accordingly, CF may be advantageously used in nonwovens to reduce man-made fibre content, improve degradability and maintain flushability while reducing or eliminating undesirable linting and/or dust production.
  • Table 7 summarizes the compositions of the nonwoven samples used for the wet lint test.
  • the wet lint tests were conducted by soaking the samples between 1 and 10 seconds prior to testing, followed by testing according to the same conditions as the dry lint test.
  • samples 8A, 8B and 10B, comprising CF exhibited a similar performance to sample 7A, which did not comprise CF, while sample 9A exhibited a higher linting percentage.
  • CF may provide lower overall hydroentanglement in a wet state, leading to higher linting.
  • Figures 15 and 16 results of linting tests on nonwoven samples are presented.
  • Figures 15A and 15B show the results of a dry linting test on a 75 gsm nonwoven sample comprising no CF and 5% CF respectively. Average measured lint percentages were 1.35 (no CF) and 0.28 (5% CF).
  • Figures 15C and 15D show the result of wet linting tests on the same samples, where the samples had been soaked overnight. Average measured lint percentages were 1.59 (no CF) and 0.18 (5% CF).
  • Figures 16A and 16B show a magnified portion of Figures 15A and 15B respectively.
  • nonwoven fabric may be subject to friction against one or more surfaces, such as machine surfaces, rolling drums, calendering units, cutters, transporters and other sheets of nonwoven fabric. Accordingly, fabrics exhibiting higher lint and dust percentages may cause significant particulate dispersion in the manufacturing and/or processing area. Particulate accumulation may be especially dangerous as it may cause health hazards and fire/explosion hazards, for example a dust explosion. Accordingly, a process and/or a product producing less lint and/or dust may be safer. It will also be understood that CF addition may thus be desirable from a manufacturing perspective to reduce dry linting regardless of the impact of CF on wet linting, depending on the intended use and characteristics of the nonwoven product.
  • Table 8 summarizes the dry and wet degradation test results for two samples, marked X and Y, where sample X contained no CF and sample Y contained 5% CF. Dry degradation tests were performed by scrubbing the samples against a ceramic tile with 750g weight for 100, 200, 300 and 500 scrubs. Wet degradation tests comprised a soaking time of 20 seconds. Degradation was rated on a scale of 1 to 10, where 10 represents total degradation and 0 represents no degradation. Representative degraded samples and corresponding degradation ratings are shown in Figure 17.
  • Figure 18 presents dry degradation results for a selection of the samples presented in Tables 6 and 7.
  • CF addition in samples S2 and 10A provided significant improvement in resistance to degradation during use. This is consistent with findings that CF contributes to improved dry tensile strength without significantly affecting the stretch of the nonwoven fabric.
  • one advantage of one or more embodiments of the methods and the product disclosed herein is that the present invention provides a product with performant structural properties while being easily disposable.
  • Another advantage of the technology disclosed herein is that the present invention provides a product that may be essentially conceived using wood pulp and mechanically obtained product thereof. [0184] Another advantage of the technology disclosed herein is that the present invention reduces the amount of lint and dust in the manufacturing process, which greatly reduces risk of unwanted fires and other accidents.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Nonwoven Fabrics (AREA)

Abstract

L'invention concerne une étoffe non tissée. L'étoffe non tissée peut comporter des fibres courtes d'un matériau à base de plante présentant une longueur comprise entre environ 2 mm et 5 mm, et des filaments de cellulose qui sont présents dans une proportion pouvant atteindre 10% en poids de l'étoffe non tissée, de telle façon que les filaments de cellulose lient les fibres courtes dans l'étoffe non tissée. Des fibres longues sont optionnellement ajoutées à l'étoffe non tissée.
PCT/IB2023/057074 2022-07-11 2023-07-10 Etoffe non tissée et procédé pour sa fabrication WO2024013645A1 (fr)

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Citations (3)

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Publication number Priority date Publication date Assignee Title
US6749718B2 (en) * 2001-05-16 2004-06-15 Uni-Charm Corporation Water-disintegratable sheet and manufacturing method thereof
WO2012017954A1 (fr) * 2010-08-04 2012-02-09 ダイセル化学工業株式会社 Tissu non tissé comprenant des fibres de cellulose et son procédé de production, et séparateur
CA2905735A1 (fr) * 2013-03-15 2014-09-25 Georgia-Pacific Consumer Products Lp Tissus non tisses constitues de fibres liberiennes courtes et individualisees, et produits fabriques a partir desdits tissus

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Publication number Priority date Publication date Assignee Title
US6749718B2 (en) * 2001-05-16 2004-06-15 Uni-Charm Corporation Water-disintegratable sheet and manufacturing method thereof
WO2012017954A1 (fr) * 2010-08-04 2012-02-09 ダイセル化学工業株式会社 Tissu non tissé comprenant des fibres de cellulose et son procédé de production, et séparateur
CA2905735A1 (fr) * 2013-03-15 2014-09-25 Georgia-Pacific Consumer Products Lp Tissus non tisses constitues de fibres liberiennes courtes et individualisees, et produits fabriques a partir desdits tissus

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SETH RAJINDER S.: "The Difference Between Never-Dried And Dried Chemical Pulps", 2001 TAPPI PEER-REVIEWED PAPER/SOLUTIONS! FOR PEOPLE, PROCESSES AND PAPER, vol. 1, no. 1, 1 September 2001 (2001-09-01), XP093130059 *

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