Nonwoven fabrics, products comprising the same and methods for manufacturing nonwoven fabrics

Abstract

A nonwoven fabric that includes a fibrous monofilament having cellulose and optionally thermoplastic fibers or man-made cellulosic fibers or non-wood derived cellulosic fibers or any mixture thereof; to fibrous monofilaments; and to methods of preparing and using such fabric and / or monofilament.

Description

[0001] The present invention relates to nonwoven fabrics and products comprising said nonwoven fabrics. Further, the invention relates to methods for manufacturing fibrous monofilaments and methods for manufacturing said nonwoven fabrics.BACKGROUND

[0002] Nonwoven fabrics are broadly defined as sheet or web structures formed from staple fiber (short) and long fibers (continuous long), bonded together mechanical, thermal, or chemical treatment. The term is used in the textile manufacturing industry to denote fabrics, such as felt, which are neither woven nor knitted. Nonwoven fabrics are used in various applications including medical applications such as protective layers, surgical masks wipes and wound dressing, gas filters and other applications such as geotextiles, composites, diaper stock, insulation, packaging, and various wipes, for example. Nonwovens may be single-use, limited life, or be very durable products. Properties and raw material of nonwovens can be tailored for each use. The amount of nonwovens used worldwide is remarkable. Recycled fabrics and oil-based materials are commonly used in nonwovens. One drawback of nonwovens is oil-based material such as polyester, acrylic and nylon is their environmental impact; such fabrics are energy-intensive to produce and poorly or not at all biodegrade.

[0003] Single-use plastic products (SUPs) used once, or for a short period of time, increase the plastic waste on the environment. Single-use plastic products end up more likely in our seas than reusable and biodegradable options. There is worldwide effort to reduce the plastic burden in our environment. In this respect, EU SUP directive aims to target the vast amount of single-use plastic, reduce litter, help develop a circular economy and promote a sustainable future. One category of potentially problematic products is globally used single-use sanitary products such as towels, tampons, health bandages and diapers and wet wipes containing nonwovens with plastic components.

[0004] However, there are various challenges related to the known solutions to provide more sustainable nonwovens and related products having any or at least with reduced share of plastic components. Generally, one could say that controllability of properties that can be attained using sustainable nonwoven fabrics, such as absorbency and resilience, tenacity, durability, etc among other properties, may still remain a challenge in a number of use cases while also manufacturing methods of sustainable nonwoven fabrics to be implemented on an industrial scale have to be thought.

[0005] Natural fibers such as cotton, linen, hemp provide a more sustainable solution compared to plastic components to reduce environmental burden raised from nonwovens. However, there is still a continuous need to find products which can be manufactured as sustainable nonwovens in industrial scale and thereby reduce the environmental burden, land usage and water consumption.

[0006] In some applications fibrous monofilament enables to replace e.g. cotton. Large-scale cotton cultivation requires significant resources of water. Cotton cultivation is widely carried out in regions already experiencing shortage of both water and food. Cotton cultivation reduces the available farming area for food production, increases consumption of water, and worsens the food and water supply problem. The use of cotton is unsustainable and replacing fiber sources are needed. Previously presented properties and production methods of paper yarn have not enabled replacing cotton.

[0007] There is a continued need for obtaining sustainable materials with desired technical and mechanical properties for nonwovens and related products and their manufacturing methods.SUMMARY

[0008] The present invention at least alleviates one or more of the above drawbacks or challenges associated with the existing solutions.

[0009] It is an aim of the invention is to provide non-woven fabrics having properties suitable for multiple uses and which are environmentally sustainable. A further aim is to provide products containing said nonwoven fabrics and manufacturing methods for fibrous monofilaments and nonwoven fabrics.

[0010] The aims of the invention are obtained with a nonwoven fabric and a product comprising said nonwoven fabric and methods for producing a fibrous monofilament and nonwoven fabric, which are characterized in what is presented in the independent claims. Some advantageous embodiments of the invention are presented in the dependent claims.

[0011] One advantage of the nonwoven fabrics and fibrous monofilaments discussed in this disclosure is that their water footprint may be remarkably lower compared to existing solutions. Use of pulp-based fibers enables also utilization and recycling of wood, pulp and pulp waste. In addition, water usage with wood-based textile fibers is remarkably lower compared with e.g. cotton.

[0012] Another advantage of the nonwoven fabric and fibrous monofilaments discussed in this disclosure is their good biodegradability. Further advantages of the present invention are described hereinafter.BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1a shows the workability of the tested monofilaments of Example 1.

[0014] FIG. 1b shows the elongation percentage of the tested monofilament

[0015] FIG. 1c shows the tenacity of the tested monofilament

[0016] FIG. 1d shows the width (in micrometers) of monofilament (marked as Fiber in the Figure)

[0017] FIG. 1e shows the gel strength of the suspension used to prepare monofilaments

[0018] FIG. 2a illustrates tensile strength (machine direction) for nonwoven comprising a fibrous monofilament described here, lyocell, and BiCo;

[0019] measurement for dry sheet is shown as a solid line and wet as dashed line

[0020] FIG. 2b illustrates tensile strength (cross direction) for nonwoven comprising a fibrous monofilament described here, lyocell, and BiCo; measurement for dry sheet is shown as a solid line and wet as dashed lineDETAILED DESCRIPTION

[0021] In the present disclosure the percentage values relating to an amount or share of raw materials are percentages by weight (wt. %) with respect to the dry monofilament / nonwoven fabric unless otherwise indicated.

[0022] In this disclosure the expression nonwoven fabrics or nonwovens refer to sheet or web structures bonded together by entangling fiber or monofilament mechanically, thermally, or chemically. Typically, they are in form of a sheet or a layer but also other forms usable e.g. as adsorbent are included. They may be made from single material (such as cellulosic fibrous MFC monofilaments here described) or from separate materials such as filaments composed of regenerated cellulose or other material, natural and man-made fibers or e.g. molten plastic filaments.

[0023] Cellulose material (pulp) is built up by a cellulose fiber matrix. The fibers that form such a matrix are fibril bundles which in turn consist of microfibrils. Through a fibrillation process the cellulose fibers are separated into a three-dimensional network of microfibrils with a large surface area. These entangled fibrils are called microfibrillated cellulose (MFC). The width of entangled fibrils in MFC may be between 50 nm to 2 μm and length or longitudinal dimension may be between 100 nanometers to 500 micrometers, such as 100 nanometers to 200 micrometers.

[0024] The method for manufacturing MFC is not limited. MFC may be produced from cellulose fibers using methods known within the art through high pressure, high temperature and high velocity impact homogenization, for instance. The homogenization process is used to delaminate or disintegrate the cell walls of the fibers and to liberate their sub-structural fibrils and microfibrils. Enzymatic and / or mechanical pre-treatments of wood fibers may also be used.

[0025] In the present disclosure expressions “non-regenerated cellulose” or “natural cellulose” refer to cellulose or cellulose fibrils or fibers that have not undergone chemical or physical modification of its macromolecular structure. Non-regenerated MFC as discussed here is substantially non-regenerated and consists mainly of crystalline structure of cellulose I. Cellulose I may have structures Iα and Iβ. Man-made cellulosic fibers commonly used e.g. in pulp & paper industry are regenerated and crystalline structure is mainly other than cellulose I. Conversion of cellulose I to cellulose II (or other forms, like cellulose III or cellulose IV) is irreversible. Thus, these forms are stable and cannot be converted back to cellulose I.

[0026] Cellulose used in this invention may originate from any plant-based material. Plant based raw material may be wood or non-wood material. The wood material can be based on softwood tree, such as spruce, pine, fir, larch, Douglas-fir or hemlock, or hardwood tree, such as birch, aspen, poplar, alder, eucalyptus or acacia, or any mixture of above. The non-wood material may be as cotton, hemp, flax, sisal, jute, kenaf, bamboo, peat, or coconut. Non-wood based natural cellulose fibers may also be derived from agricultural residues, grasses, or other plant substances such as straw, leaves, bark, seeds, hulls, flowers, vegetables, or fruits. Woody plants have a good availability, small environmental burden and the quality of fiber is good. The above applies both to non-regenerated cellulose and also regenerated and processed forms of cellulose.

[0027] The present disclosure relates to a nonwoven fabric comprising:

[0028] (a) 20 to 100 wt.-% of the total weight of the nonwoven fabric a fibrous monofilament comprising:

[0029] i. 80 to 98 wt.-% of the weight of component (a) non-regenerated microfibrillated cellulose (MFC); and

[0030] ii. 2 to 20 wt. % of the weight of component (a) dispersion agent(s) selected from carboxymethylcellulose (CMC), hydroxyethyl cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC) hydroxyethyl methyl cellulose (HEMC), methyl ethyl hydroxyethyl cellulose (MEHEC), hydroxypropyl cellulose (HPC), ethyl cellulose (EC), and starch or any mixture thereof, and

[0031] (b) 0 to 80 wt.-% of the total weight of the nonwoven fabric thermoplastic fibers or man-made cellulosic fibers or non-wood derived cellulosic fibers or any mixture thereof.

[0032] The share of the fibrous monofilament is biodegradable. Such filament may have good absorption properties. It may also be a good for thermal insulation.

[0033] The fibrous monofilament may further comprise additives selected from strength additives, hydrophobic adhesives, pigment(s), and / or other modifier(s). These additives can be used for tailoring properties of the produced nonwoven fabric as appreciated by the skilled person.

[0034] The dispersion agent may be a cellulose derivative such as carboxymethylcellulose (CMC), hydroxyethyl cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), methyl ethyl hydroxyethyl cellulose (MEHEC); hydroxypropyl cellulose (HPC); ethyl cellulose (EC) and starch or any mixture thereof. In one embodiment the dispersion agent is carboxymethyl cellulose (CMC), optionally with an additional dispersion agent. Also anionic polyacrylamide (aPAM) can be used as a dispersion agent, alone or in combination with another dispersion agent.

[0035] The dispersion agent has an effect on shear strength of the fibrous monofilament. The dispersion agent may be used in an amount of 0.5 to 20 wt.-% of the total weight of the dry fibrous monofilament. In one embodiment the dispersion agent is used in amount of 5 to 20 wt.-%, or 2 to 16 wt.-% or about 13 to 16 wt.-% such as about 14 wt.-% of the total weight of the fibrous monofilament.

[0036] For example, CMC may be used in an amount of 0.5 to 20 wt.-% of the total weight of the dry fibrous monofilament. In one embodiment CMC is used in amount of 5 to 20 wt.-% or about 10 wt.-% of the total weight of the material fibrous monofilament. In one embodiment CMC is used 4 to 5 wt.-% of the total weight of the material fibrous monofilament. In one embodiment CMC is used 14 to 16 wt.-% of the total weight of the fibrous monofilament.

[0037] The strength additive may be a dry strength agent such as polyacrylamide resin (amphoteric / anionic / cationic), starch, vegetable gum, carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and latex or it may be a wet strength agent such as cationic glyoxylated resins, polyamidoamine-epichlorohydrin resins (PAE), polyamine-epichlorohydrin resins, ureaformaldehyde (UFH), epoxide resins, glyoxylated polyacrylamides (G-PAM), polyethylene oxide (PEO) and one or more suitable cross-linking agent such as polyurethane (PU) known in the art or a durable water repellent (DWR).

[0038] Some chemicals have effect on e.g. dispersion and strength properties. If desired, e.g. two different qualities of CMC may be used.

[0039] At simplest a nonwoven (nonwoven fabric) may comprise only MFC and CMC thereby being completely and easily biodegradable.

[0040] The strength agent may be G-Pam. The amount of G-Pam may be 0.5 to 3 wt.-% of the total weight of the fibrous monofilament, such as 2 wt.-% of the total weight of the dry fibrous monofilament. Use of G-Pam allows modifying the wet strength level from temporary towards permanent.

[0041] The strength agent may be anionic polyacrylamide (aPAM). The amount of APAM may be 0.5 to 5 wt.-% of the total weight of the dry fibrous monofilament, such as 2 to 4 wt.-% of dry weight of the fibrous monofilament. The higher is the amount of aPAM the better is the elasticity of the nonwoven fabric. aPAM is a super-flocculant also usable as an additional dispersion agent. It improves alignment of fibers in the suspension while they are extruded through a small nozzle on to a solid surface. aPAM has also effect on suspension rheology.

[0042] The strength agent may be PEO in an amount of 0.5 to 5 wt.-% of the total weight of the dry fibrous monofilament, such as 1 to 3 wt.-% of the fibrous monofilament. PEO increases elasticity of the monofilament and the fabric here described. PEO has also effect on suspension rheology.

[0043] The strength additive, especially the wet strength additive, must be cured (activated) by a heat treatment in order to obtain desired filament properties. Curing conditions can be optimized based on the additive and desired properties of the final product (filament, yarn, fabric). For example, when PAE is used as a wet strength agent in the monofilament of fabric here described, wet tenacity and elongation increase after curing.

[0044] Tenacity is a customary measure of strength of a fiber or yarn. It is usually defined as the ultimate (breaking) force of the fiber / yarn (in gram-force units) divided by the linear density. Tenacity is often expressed as cN / (d) tex. Linear density is a value expressing the fiber / yarn weight in grams per 1 000 meters of fiber / yarn (tex) or grams per 10 000 meters of fiber / yarn (dtex).

[0045] The hydrophobic adhesive may be alkyl ketene dimer (AKD, an alkaline or neutral sizing agent), alkenyl succinic anhydride (ASA, sizing agent), rosin (acidic sizing agent), natural waxes, and modified sunflower-based adhesive (MSOHO) or any mixture thereof.

[0046] Said hydrophobic adhesive may be AKD. The amount may be 0.5 to 10 wt.-% of the total weight of the dry fibrous monofilament, such as 2 to 5 wt.-% of the total weight of the dry fibrous monofilament. As a hydrophobic adhesive AKD reduces the adsorption properties of the monofilament or nonwoven fabric here described. AKD may also increase strength of the monofilament or fabric here described.

[0047] The fibrous monofilament may comprise additive(s) between 0.0 and 18 wt.-%, between 0.05 and 15 wt.-%, preferably between 0.1 and 10 wt.-%.

[0048] In one embodiment a nonwoven fabric comprises:

[0049] (a) 20 to 100 wt.-% of the total weight of the nonwoven fabric a fibrous monofilament consisting of:

[0050] i. 80 to 98 wt.-% of the weight of component (a) non-regenerated microfibrillated cellulose (MFC); and

[0051] ii. 2 to 20 wt. % of the weight of component (a) dispersion agent(s), and

[0052] iii. 0 to 18 wt.-% other additives; and

[0053] (b) 0 to 80 wt.-% of the total weight of the nonwoven fabric thermoplastic fibers or man-made cellulosic fibers or non-wood derived cellulosic fibers or any mixture thereof.

[0054] Said man-made cellulosic fiber(s) may be selected from Lyocell, viscose, modal, acetate, rayon and recycled textile waste fibers or any mixture thereof. In one embodiment the man-made fiber is Lyocell. Thin and long man-made cellulosic fibers may improve strength (estimated e.g. as resilience, tenacity, durability, bursting strength) of the fabric. In addition to the above discussed agent e.g., pigments and softening agents may be used.

[0055] Said thermoplastic fibers may be selected from polypropylene, polyamide, polyester, polypropylene / polyester, and bi-component short cut fibers. Thermoplastic fibers improve durability of the fabric and may provide stretching properties and static properties. Static properties are especially important in various gas filters including face masks. In addition, thermoplastics are suitable for thermobonding fibers and monofilaments of the nonwoven fabric.

[0056] Said non-wood derived cellulosic fibers may be selected from cotton, hemp, flax, sisal, jute, kenaf, bamboo, peat, and coconut or a mixture thereof, especially cotton, flax, and hemp or a mixture thereof. Non-wood cellulosic fibers may improve durability of the fabric. In addition, non-wood cellulosic fibers may can be used for tailoring adsorption properties.

[0057] Also, wool or silk can be used in the nonwoven fabric. Wool is especially useful when insulation properties are desired.

[0058] The nonwoven fabric may comprise 80 to 98 wt.-% of the weight of the fabric non-regenerated MCF and 2 to 20 wt. % of dispersion agent(s). Such nonwoven readily disperses in an aqueous solution and is easily biodegradable in most natural environments.

[0059] In one embodiment the nonwoven is made of monofilament, which consists of:

[0060] i. 80 to 98 wt.-% of non-regenerated microfibrillated cellulose (MFC); and

[0061] ii. 2 to 20 wt. % of dispersion agent(s), and

[0062] iii. 0 to 18 wt.-% other additivescalculated from the weight of the dry monofilament.

[0063] The nonwoven may be a nonwoven sheet, such as a single use wipe. A nonwoven may comprise, or consists of, non-regenerated (cellulose I crystal type) fibers in form of MCF and dispersion agent(s). Optionally the nonwoven further comprises strength additives, hydrophobic adhesives, pigment(s), and / or other modifier(s). Such nonwoven and also monofilament described here are biodegradable in a moist or aqueous natural environment and also compostable, as evidenced in the experimental section. The tests have shown that biodegradability of monofilaments and fabric here described are on the same level as cellulose.

[0064] Following properties may be given as on example of the nonwoven described here, suitable for single use wipes and having a square mass varying between and 90 g / m2 (DIN EN 29073-1:1992-08), thickness varying between 0.50 to 100 μm (DIN EN ISO 9073-2:1997-02), air permeability 2100 to 850 l / m2 / s (DIN EN ISO 9237:1995-12).

[0065] Tear strength (dry) using trapezoid procedure (DIN EN ISO 9073-4:2021-05) may be varying between 5 to 35 N, e.g. 22.5 N (lengthwise), or / and varying between 40 and 70 N. e.g. 58.8 (cross). Respective values in wet may be about 17.7 N ja 50.3N+ / −5N. Bursting strength (DIN EN ISO 13938-2:2020-03) may be varying between 5 and 65 kPa. Stretches may be 50 and 28%, respectively.

[0066] The present disclosure also discloses a product comprising a nonwoven here described and optionally one or more protective layers and / or supporting framework and / or adsorbed moist or chemicals and / or means for fastening the nonwoven fabric.

[0067] The product may be a surgical mask, a filter layer or a protective curtain comprising at least one layer of nonwoven fabric here described and at least one protective layer.

[0068] In products for filtration of air or gases the nonwoven fabric being as a layer or sheet may comprise thermoplastic fibers, e.g. 5 to 50 wt.-% such as about 20 wt. % from the total weight of the nonwoven fabric. Thermoplastic fibers provide static properties for adhering airborne particles. In addition, they enhance durability and are suitable as such for thermobonding the fabric.

[0069] Protective layer may be used to protect the nonwoven filter layer from external abrasion but also to provide a comfort layer between the skin of the user and the active nonwoven filtration layer.

[0070] In gas or air filtration the layer, such as the nonwoven fabric here described, is often thin and flexible and thus may require to be supported in such applications. Air purification and filter systems may comprise several protective layers, prefilter layers and / or filter layers. Typically, the layers of air purification and filter systems are assembled in connection with a supporting structure which may e.g. form a channel for gas flow. Respectively, e.g., in a face mask the protective layers may also support the nonwoven filter layer and may allow attaching suitable fixing means. In addition to filtration, also static and antipathogenic properties may introduced as separate active layers or the active properties may be included in the nonwoven layer here described.

[0071] The product may be an impregnated sheet of nonwoven fabric here described. The sheet may be a limited-use wipe or a single-use wipe. It may be impregnated with an aqueous liquid optionally comprising purifying agent(s), aroma, deodorizing agent, moisturizing agents, disinfectants or an alcoholic solution (such as ethanol, isopropanol) optionally containing further solutions or e.g., oily liquid. Fields of use include personal hygiene, disinfection, sanitation, and cleaning surfaces, for example. The impregnated sheet may be individually wrapped.

[0072] The present disclosure also relates to a method for manufacturing a fibrous non-regenerated microfibrillated cellulose based monofilament here described for manufacturing a nonwoven fabric. The monofilament may be used in other applications. The method comprises steps of forming an aqueous suspension comprising 80-98 wt.-% of water (based on the suspension weight) and 2-20 wt.-% dry matter, wherein the dry matter comprises MFC and at least one dispersion agent, and extruding the suspension into a monofilament and drying the monofilament.

[0073] The present disclosure also relates to a fibrous non-regenerated microfibrillated cellulose based monofilament. The monofilament may comprise, or consist of, non-regenerated microfibrillated cellulose (MFC) and a dispersion agent(s). The properties can be modified as discussed above in connection of a nonwoven fabric.

[0074] The term “fibrous monofilament” as used here refers to a continuous length of individual fibrils grouped and extending generally along the longitudinal dimension of the cellulose monofilament. The fibers may be interlocked together in order to form a permanent monofilament structure. The monofilament cannot be opened or disassembled. Fibers grouped together cannot be separated into substructures, such as fiber ribbons or strips via e.g., mechanical cutting, grinding or chemical separating means. Disintegration of fibrous monofilament yields only individual fibrils. The fibrous monofilament may comprise continuous length of several meters or kilometers. Term “monofilament” refers to a single strand filament produced by extruding a polymer suspension. Fibrous monofilament may also be called a monofilament fiber.

[0075] The fibrous monofilament here described may have, when measured following ASTM 3822 / D3822M-14 standard, a tenacity at least 1 cN / dTex or at least 1.5 cN / dTex or 2 cN / dTex.

[0076] In relation of longitudinal direction, the monofilaments described here may have a thickness of about 5 to 30 μm and a width of about 30 to 300 μm (cross section may be flattened). A high cross sectional aspect ratio of the monofilaments has effect on the flexibility of the monofilament. The cross-sectional aspect ratio may be 30 to 300 μm: 2 to 30 μm or 30 to 200 μm: 1 to 6 μm or 30 to 120 μm: 5 to 10 μm. Monofilaments described here comprise “non-regenerated cellulose”. It is to be noted that the desired properties are dependent on the field of use.

[0077] Usual order of adding the components (added to an aqueous solution) to form the aqueous suspension in pulp & paper manufacture is MFC, strength agent (e.g. PAE), dispersing agent (e.g. CMC) and in the following stage(s) possible hydrophobic agent and further strength agents. Possible cross-linker agent may be added as early as possible in order to allow the cross-linking reaction to proceed.

[0078] When manufacturing a monofilament here described, the above order may be used. First MFC and then a dispersion agent may be added to the aqueous suspension and thereafter, depending on the field of application a strength agent, optional hydrophobic adhesive and possible further additives, e.g. further strength agents. One exemplary recipe with a suitable adding order is MFC+CMC+PAE+AKD+aPAM. It is to be noted that certain crosslinker activity may require contact with the fiber at early state already. Alternatively, the CMC (or other dispersion agent) may be added before MFC.

[0079] A person skilled in the art is able to determine suitable pH parameters for activity of strength agents and adhesives using his common general knowledge and the material provided by the chemical manufacturer.

[0080] It is to be noted that in the simplest embodiment, it is possible to produce a fibrous monofilament and / or a nonwoven comprising, or consisting of, only MFC and dispersing agent such as CMC. In such case the amount of CMC is at least 4 wt.-%, preferably at least 8 wt. %, 10 wt.-%, 12 wt.-% or even 14 wt. % of the total dry weight of the sheet.

[0081] A fibrous monofilament here described is made of an aqueous suspension. Aqueous suspension comprises water, non-regenerated cellulosic fibers and at least one dispersion agent, typically a cellulose derivative.

[0082] The fibrous monofilament may comprise density between 800 and 1700 kg / m3, such as 1500 kg / m3. The fibrous monofilament may comprise linear mass density of 3-100 grams per 1000 meters, being 2-10 dtex; or preferably linear mass density of 3-10 dtex. The fibrous monofilament may comprise tenacity of 0.5-3.0 cN / dtex, when measured according to ASTM 3822 / D3822M-14.

[0083] It is possible to include also other wood-based pulp fibers or other short natural cellulose fibers like cotton or flax or other short man-made cellulose fibers, such as regenerated cellulose fibers like viscose, Cupro or Lyocell. Possible further fibers must be refined to substantially same size as MFC when within the monofilament comprising non-regenerated MFC.

[0084] In the manufacturing method of the fibrous monofilament the aqueous suspension is directed (extruded) through a small nozzle where fibers align (orient) well with the flow. The nozzle feeds the aqueous suspension to a solid surface which is followed by drying to obtain the fibrous monofilament. Thus, manufactured fibrous monofilament is continuous but it may be post processed into shorter lengths by any of suitable methods known in the art. Also chemical post treatments such as dyeing are possible. Thickness of the fibrous monofilament may be affected at least in part by adapting manufacturing speed, aqueous suspension concentration and nozzle geometry. Filaments and structures of short cellulosic fibrils tend to become disintegrated in water. This property also enhances their biodegradability.

[0085] Properties of the fibrous monofilament and nonwoven fabric may be tailored. For example, thickness and strength properties can be adapted to the utilization and use. Also, properties like absorbency, softness, flexibility, sustainability, wear-sustainability, shape stability, elasticity / inelasticity and / or combinability with other materials or yarns may have effect on utilization possibilities of the fibrous monofilament. Methods and chemicals known within the textile industry can be used. Waxes can be used to modify the softness and absorbency of the filament and / or fabric. AKD as a hydrophobic agent reduces absorbency, increases the strength and resilience, and reduces the softness of the fabric when used in high amount.

[0086] The present disclosure further relates to a method for manufacturing a nonwoven fabric comprising the steps of:

[0087] (a) providing fibrous monofilament comprising

[0088] i. 80 to 98 wt.-% of the weight of component (a) non-regenerated MFC; and

[0089] ii. 2 to 20 wt. % of the weight of component (a) dispersion agent(s);

[0090] iii. 0 to 18 wt.-% of other additives

[0091] (b) optionally providing further fibers selected from thermobonding polymers, man-made cellulosic fibers, non-wood cellulosic fibers and any mixture thereof; and

[0092] (c) depositing fibrous monofilaments of (a) and optional fibers of (b) in a random pattern onto a surface to form nonwoven fabric and optionally drying the formed fabric.

[0093] Step (c) may comprise a step of carding, wet or air laying, or spun laying the deposited filaments of (a) and optional fibers of (b) to form nonwoven fabric.

[0094] Step (c) may comprise a step of needling, hydroentangling, thermobonding or chemically bonding the formed fabric.

[0095] Step (c) may be followed with further steps such as impregnating, smoothening, heat-setting, drying or calibrating the formed fabric.

[0096] In one embodiment the nonwoven fabric or fibrous monofilament comprises only MFC and a dispersing agent such as CMC. In such a case the amount of CMC is at least 4 wt.-%, preferably at least 8 wt. %, 10 wt.-%, 12 wt.-% or even 14 wt. % of the total dry weight of the fabric or said fibrous monofilament.

[0097] It should be understood that the embodiments given in the description above are for illustrative purposes only, and that various changes and modifications are possible within the scope of the disclosure. It is also to be understood that the terminology employed herein is for the purpose of description and should not be regarded as limiting. The features described here as separate embodiments may also be provided in combination in a single embodiment. Also, various features described here in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0098] The invention is described below with the help of examples. The examples are given only for illustrative purpose, and they do not limit the scope of the invention.EXAMPLESExample 1. Properties of Fibrous Monofilaments with Various Recipes

[0099] Monofilaments were formed as explained in WO 2018 / 115577 A1. The compositions of the monofilament samples are given in Table 1 below.TABLE 1Compositions of the test samplesTrial noRecipe1 REFMFC + CMC 14% + aPam 1.4% + PAE 2% + 0.5% AKD2MFC + CMC 14% + aPam 1.4% + PAE 2%3MFC + CMC 14% + aPam 1.4%4MFC + CMC 14%5MFC + CMC 4%6MFC + CMC 4% + PAE 2% + AKD 0.5%7MFC + CMC 4% + aPam 1.4% + PEO 0.5%8MFC + CMC 4% + aPam 1.4% + PEO 0.5% + PAE 2% +AKD 0.5%9MFC + CMC 4% + PEO 5%10MFC + CMC 4% + PEO 5% + PAE 2% + AKD 0.5%

[0100] The samples were evaluated for workability, elongation %, tenacity (cN / dTex), filament width (u) and gel strength (Pa).

[0101] The measurements followed standard ASTM 3822 / D3822M-14 at RH 65% (+ / −2%) and temperature 20° C. (+ / −2° C.). Unless otherwise explained, the same standard was used also in the following experiments.Results

[0102] Results are shown in FIGS. 1a to 1e and table 2 below.TABLE 2Average results, Trial 1 represents a referenceGelstrengthMonofilament propertiesDSC,of suspen-LD,Elonga-Tenacity,Work-Width,Trial%siondTextion, %cN / dTexabilityμm15.0359565.827.461.961467024.8052304.557.622.121618034.9346854.577.202.101526344.9750004.687.441.971476554.7888984.403.901.14449764.97100044.721.380.51711774.7987754.177.462.151607384.7576314.356.391.651066894.7780124.407.561.9014479104.7582984.607.141.5911498Conclusions

[0103] It is shown that in simplest it is possible to produce a monofilament using only MFC and dispersion agent in sufficient amount. A monofilament comprising only 4 wt.-% could be formed (spun) into a monofilament; 14 wt.-% provided a good tenacity, elongation and workability (sample 4).

[0104] Sample 7 demonstrates that even with 4 wt.-% CMC a tenacity level of the reference sample is obtained when PEO and a-Pam are added, PEO alone (sample 9) is not sufficient to provide tenacity.

[0105] When sample 3 and 4 are compared, it can be seen that CMC without a-Pam provides a good rheology (gel strength) i.e. it has sufficient dispergation properties.

[0106] When sample 8 and 10 are compared, it can be seen that AKD slightly reduces the tenacity. However, AKD is a hydrophobic adhesive has a role in controlling water adsorption.

[0107] In tested compositions PAE was needed to obtain a good wet tenacity, only 2 wt.-% results are shown. PEO was not remarkable in the properties tested here.Example 2: Effect of HEC on Monofilament

[0108] In this experiment it was shown that HEC added to the monofilament recipe increased elasticity of the monofilament. Table 3 below summarized the tested recipes and the measured properties. The fibrous monofilaments were prepared as explained in WO 2018 / 115577.TABLE 3DSCHECPAECMCa-PamElonga-Tenacity,Work-Rheology%%%%%tion, %cN / dTexabilityG′REF 15.402121.47.261.921396480(CMC 12%)REF 25.402101.06.951.961368588(CMC 10%)REF 35.402141.46.931.991386254(CMC 14%)HEC 10%5.4102121.47.411.811344966(CMC 12%)HEC 15%5.4152121.47.751.911484466(CMC 12%)HEC 20%5.4202121.47.11.711224113(CMC 12%)HEC 25%5.4252121.48.031.941553788(CMC 12%)HEC 25%5.4252101.07.431.831364361(CMC 10%)HEC 25%5.4252141.48.041.831483507(CMC 14%)

[0109] It is shown e.g. that HEC increases the elasticity of the monofilament.Example 3A: Properties of Nonwowens

[0110] The suspension and monofilaments were formed as explained in WO 2018 / 115577 A1. The monofilament used comprised 82.1 wt.-% MFC, 14 wt.-% CMC 1.4 wt.-%, A-PAM, 2 wt.-% PAE and 0.5 wt.-% AKD. Percentages are based on the dry weight of the fibrous monofilament, or the nonwoven formed from said filament. An aqueous suspension used for monofilaments had a consistency of about 5 wt.-%.

[0111] Needle punched non-woven fabrics were prepared using conventional methods in parallel samples. The tests were performed by the Saxon Textile Research Institute eV (STFI)

[0112] Nonwovens were tested for mass per unit area, thickness, air permeability, tensile strength, tear strength and burst strength.Samples

[0113] The nonwoven test series a comprised 70 wt.-% or 80 wt.-% fibrous monofilaments described here and 30 wt.-% or 20 wt.-% lyocell, respectively.

[0114] The filaments and lyocell were carded and needle punched (samples 1 and 2) or prepared by aqua-jet method (sample 3) into non-woven fabrics using conventional methods.Test Program was the Following

[0115] Conditioning and testing atmosphere: ((20.0±2.0° C.) / (65.0±4.0)) % humidity are shown in Table 4 belowTABLE 4Pos.Test methodStandard(1)Mass per unit areaDIN EN 29073-1: 1992 August(2)ThicknessDIN EN ISO 9073-2: 1997 FebruaryMethod A Area: 25 cm2Pressure: 5 cN / cm2 Number ofspecimens: 10(3)Air permeabilityDIN EN ISO 9237: 1995 DecemberArea: 20 cm2Pressure: 200 Pa Number of specimens: 10(4)Tensile test, nonwovenDIN EN 29073-3: 1992 AugustGauge length: 200 mm Test speed: 100mm / min(5)Tear strength,DIN EN ISO 9073-4: 2021 Maytrapezoid procedureTest date: 5 Aug. 2021(6)Bursting properties,DIN EN ISO 13938-2: 2020 Marchpneumatic methodEquipment: James H. Heal TruBurstModel 610Test area: 50 cm2State of specimens: conditioned(7)Velocity of soakingDIN 53924: 2020 Septemberwater (method byTest date: 23 Jul. 2021determining the risingheight)(8)Measurement ofDIN EN ISO 11092: 2014 Decemberthermal and water-Number of specimens: 3vapour resistanceSurface upunder steady-stateTest conditions airflow: 20° C. / 65%conditions (sweatinghumidity Temperature of measuringguarded- hotplate test)surface: 35° c. Test date: 20-27Jul. 2021(6)Bursting properties,DIN EN ISO 13938-2: 2020 Marchpneumatic methodEquipment: James H. Heal TruBurstModel 610Test area: 50 cm2State of specimens: conditionedTABLE 5ResultsTestPos.methodUnitSample 01Sample 02Sample 03(1)Mass per unit areaSingle valuesg / m2187.41201.25156.27191.02201.02157.06193.65211.65171.44200.90183.57168.19209.74197.94170.51Mean valueg / m2196.54199.08164.69Std. dev.g / m28.88110.1047.431Coeff. of var%4.515.084.51(2)ThicknessMean valuemm3.363.451.38Coeff. of variation%6.325.784.47(3)Air permeability at 200 PaMean valuel / m2 / s579.0423.2310.7Coeff of var.%8.858.5115.92Tensile strength and elongation of nonwovens(4a)Dry conditioninglengthlengthlengthDirectionwisecrosswisecrosswisecrossTensile strengthMeanN21.158.2724.5267.6244.5112.5Stand. Dev.N0.572.521.475.661.793.0Coeff. of var.%2.724.336.018.374.052.67Conf. int, 95%N0.713.131.837.032.223.73Elongation at maximum forceMean%85.540.9373.0134.3430.933.66Std. dev.%2.311.1441.611.553.402.91Coeff. of var.%2.713.512.214.5111.58.64Conf. int., 95%%2.871.782.001.924.223.61(4b)Wet conditionlengthlengthlengthDirectionwisecrosswisecrosswisecrossTensile strengthMeanN21.6475.8919.5552.7837.7172.70Std dev.N0.947.980.893.721.752.29Coeff. of var.%4.3310.524.537.054.633.15Conf. int., 95%N1.169.911.104.622.172.84Elongation at maximum forceMean%66.9440.8755.6536.9150.542.49Std dev.%8.252.772.210.751.931.60Coeff. of var.%12.336.783.972.033.853.76Conf. int., 95%%10.253.442.750.932.391.98(5)Tear strength, trapezoid procedurelengthlengthlengthDirectionwisecrosswisecrosswisecrossMaximum forceN17.7226.2817.2627.2125.162.5Coefficient%13.6910.0214.303.848.1115.81of variation(6)Bursting properties, pneumatic methodBursting strengthMeankPa111.1894.5278.28Coefficient%8.2512.1014.77of variationBursting distensionMeanmm20.8618.4819.86Coefficient%3.063.645.0of variation(7)Velocity of soaking waterlengthlengthlengthDirectionwisecrosswisecrosswisecrossRising heightafter 10 sSingle valuesmm264796364798374699374787374776Meanmm2.86.646.88.47.2Rising heightafter 30 sSingle valuesmm91412141111913915111591410141216817915131581410141212Meanmm8.614.41014.411.813.8Rising heightafter 60 sSingle valuesmm141817191516131813201619132015191822122215211919121916191917Meanmm1319.415.219.617.418.6Rising heightafter 300 sSingle valuesmm192630333238222528353342202730343645233028363743252829363739Meanmm21.827.22934.83541.4(8)Thermal resistance Rc, under steady-state conditions(sweating guarded-hotplate test)Single valuesm2K / W0.1520.1580.0460.1550.1510.0440.1550.1520.044Meanm2K / W0.1540.1540.044Example 3B: Properties of NonwowensThe suspension and monofilaments were formed as explained in WO 2018 / 115577 A1. The monofilament used comprised 82.1 wt.-% MFC, 14 wt.-% CMC 1.4 wt.-%, A-PAM, 2 wt.-% PAE and 0.5 wt.-% AKD. Percentages are based on the dry weight of the fibrous monofilament, or the nonwoven formed from said filament. An aqueous suspension used for monofilaments had a consistency of about 5 wt.-%.Sample 01 is 70% fibrous monofilament, 30% Lyocell, average 80 gsm

[0118] Sample 02 is 50% fibrous monofilament, 50% Lyocell, average 80 gsm

[0119] Sample 03 is 70% fibrous monofilament, 30% Lyocell, average 45 gsm

[0120] Sample 04 is 50% fibrous monofilament, 50% Lyocell, average 45 gsm

[0121] Samples were carded, hydroentangled and spunlaced (written aqua jet or hydroentanglement).Methods(1) Mass per unit area: DIN EN 29073-1:1992-08

[0123] (2) Thickness: DIN EN ISO 9073-2:1997-02; Area: 25 cm2; Pressure: 5 cN / cm2

[0124] (3) Air permeability: DIN EN ISO 9237:1995-12; Area: 20 cm2; Pressure: 200 Pa

[0125] (4) Tensile test, nonwoven: DIN EN 29073-3:1992-08; Gauge length: 200 mm; Test speed: 100 mm / min

[0126] (5) Tear strength, trapezoid procedure: DIN EN ISO 9073-4:2021-05

[0127] (6) Bursting properties, pneumatic method: DIN EN ISO 13938-2:2020-03; Equipment: James H. Heal TruBurst Model 610; Test area: 50 cm2; State of specimens: conditioned

[0128] (7) Velocity of soaking water (method by determining the rising height): DIN 53924:2020-09TABLE 6ResultsPosTest methodUnitSample 01Sample 02(1)Mass per unit areaSingle valuesg / m288.8074.8853.9253.9289.2874.4046.7246.7285.2874.8843.5243.5286.4074.2445.9245.9281.2883.3645.1245.12Mean val.g / m286.2176.2547.0436.51Std. dev.g / m23.2153.9284.0242.704Coeff. of var.%3.735.148.557.41(2)ThicknessMean val.mm0.940.890.640.52Coeff. of var.%3.795.116.708.54(3)Air permeability at 200 PaMean val.l / m2 / s890.9933.11303.02106.0Coeff. of var.%12.465.419.1211.98(4)Tensile strength and elongation of nonwovens(4a)Dry conditionlength-length-DirectionwisecrosswisecrossTensile strengthMeanN22.4858.7723.7777.33Std. dev.N2.254.161.536.32Coeff. of var.%10.027.076.438.17Conf. int. 95%N2.795.161.907.84Elongation at maximum forceMean%49.8827.9458.8031.26Std. dev.%7.522.335.822.55Coeff. of var.%15.078.339.908.16Conf. int. 95%%9.332.897.233.17(4b)Wet conditionlength-length-DirectionwisecrosswisecrossTensile strengthMeanN17.7150.2929.0794.46Std. dev.N1.600.583.724.66Coeff. of var.%9.051.1512.784.94Conf. int. 95%N1.990.724.615.79Elongation at maximum forceMean%58.9740.5060.2836.68Std. dev.%5.482.903.800.68Coeff. of var.%9.307.176.301.86Conf. int. 95%%6.813.604.720.85PosTest methodUnitSample 03Sample 04(4)Tensile strength and elongation of nonwovens(4a)Dry conditionlength-length-DirectionwisecrosswisecrossTensile strengthMeanN10.9720.317.3818.20Std. dev.N0.621.410.301.62Coeff. of var.%5.656.944.138.88Conf. int. 95%N0.771.750.382.00Elongation at maximum forceMean%44.4629.5265.3433.59Std. dev.%3.002.103.243.17Coeff. of var.%6.767.134.969.43Conf. int. 95%%3.732.614.023.93(4b)Wet conditionlength-length-DirectionwisecrosswisecrossTensile strengthMeanN8.1124.6911.5533.26Std. dev.N0.564.291.103.83Coeff. of var.%6.9117.369.4911.50Conf. int. 95%N0.695.321.364.75Elongation at maximum forceMean%62.2439.2263.8237.70Std. dev.%6.092.014.543.18Coeff. of var.%9.785.127.118.45Conf. int. 95%%7.562.495.643.95PosTest methodUnitSample 01Sample 02(5)Tear strength, trapezoid procedurelength-length-DirectionwisecrosswisecrossMax. forceN12.2630.9417.2242.92Coeff. of var.%10.6216.1519.9220.69(6)Bursting properties, pneumatic methodBursting strengthMeankPa62.986.1Coeff. of var.%8.627.50Bursting distensionMeanmm19.619.6Coeff. of%7.737.73var.PosTest methodUnitSample 03Sample 04(5)Tear strength, trapezoid procedurelength-length-DirectionwisecrosswisecrossMax. forceN6.9515.535.5011.55Coeff. of var.%10.7315.914.588.80(6)Bursting properties, pneumatic methodBursting strengthMeankPa37.15.2Coeff. of var.%1.6368.71Bursting distensionMeanmm22.823.9Coeff. of var.%3.562.32PosTest methodUnitSample 01Sample 02(7)Velocity of soaking waterlength-length-DirectionwisecrosswisecrossRising heightafter 10 sSingle valuesmm1211121411121514141014131310121412101414Meanmm12.410.613.413.8Rising heightafter 30 sSingle valuesmm1918192019172323201621191815192218162223Meanmm18.816.420.821.4Rising heightafter 60 sSingle valuesmm2515242424242730242128232422233024222530Meanmm24.220.825.427.4Rising heightafter 300 sSingle valuesmm3638393738394344383441353835394336374345Meanmm37.236.64140.8PosTest methodUnitSample 03Sample 04(7)Velocity of soaking waterlength-length-DirectionwisecrosswisecrossRising heightafter 10 sSingle valuesmm45865489558846684489Meanmm4.44.87.68Rising heightafter 30 sSingle valuesmm61012978131379131461110147121213Meanmm6.6101212.6Rising heightafter 60 sSingle valuesmm91216131110171810121719915131910201718Meanmm9.813.81617.4Rising heightafter 300 sSingle valuesmm2224222223222229242523272027202722322425Meanmm22.22622.226

[0129] Conclusions:

[0130] It was shown that nonwoven made by needle punching technology has better thermal properties (insulation) than respective fabric made by Aqua jet-technic. The needle punched fabric is also thicker.

[0131] Air permeability of 70 wt.-% of.-% fibrous monofilaments described here and 30 wt.-% lyocell was better compared to 80 wt.-% of wt.-% fibrous monofilaments described here and 20 wt.-% lyocell.

[0132] Thus, both the monofilament and possible other constituents of the fabric as well as technology used in manufacturing the fabric have an effect on the properties of the fabric. This provides numerous ways to tailor nonwovens for various applications.Example 4: PAE Curing

[0133] The monofilaments were prepared as explained in WO 2018 / 115577. The compositions of the fibrous monofilaments were 84.6 wt.-% MCF, CMC 12 wt.-%, PAE 2 wt.-% and aPam 1.4 wt.-%.

[0134] The heat treatment / curing of the filaments was carried out by keeping the fiber at 120° C. for 10 minutes, and at 80° C. for 12 hours or 24 hours. 120° C. was in laboratory oven conditions, 80° C. was used to evaluate large scale process (heated room).TABLE 7CuringWet Tenacity (cN / dTex)Time & temp.Same dayafter 1 weekafter 2 weeksNo curing0.210.580.4910 min, 120° C.0.920.831.0012 h, 80° C.0.770.840.8224 h, 80° C.0.780.860.91

[0135] The results are shown in table 7 above show that a sample without curing does not have satisfactory wet tenacity, even it increases a bit during the time. Sample with 10 min, 120° C. curing in a laboratory scale is used as a refence.

[0136] In the laboratory scale each monofilament has been subjected to even curing. Experiments in 80° C. are larger scale experiments that could be performed. It was shown that curing time of 12 hours is sufficient to ensure almost laboratory scale curing, longer time at the same temperature did not improve tenacityExample 5: Biodegradability in Aqueous Environment

[0137] The monofilaments used in this experiment and also for preparation on nonwoven were formed as explained in WO 2018 / 115577. The compositions of the fibrous monofilaments were 84.6 wt.-% MCF, CMC 12 wt.-%, PAE 2 wt.-% and aPam 1.4 wt.-%

[0138] The biodegradation of monofilament material (recipe above) was evaluated in an aqueous anaerobic biodegradation test. The test medium was anaerobic digester sludge obtained from a sewage plant treating primarily domestic waste. A set of 12 equal test vessels with a total volume of 120 ml each was used. Each test vessel was filled with 90 g test medium and (except for the control and DIC reactors) 23 mg of reference item (microcrystalline cellulose powder) or test item (fine fibers, added as received). The reactors were kept at 35° C.±2° C. in a water bath. The DIC reactors are taken along to make a correction for the inorganic carbon that is dissolved in the test medium at start of the test. The test was performed in triplicate and the total test duration was 60 days.

[0139] Tests for biodegradability were performed by OWS nv, Belgium following standard ISO 11734 Evaluation of the “ultimate” anaerobic biodegradability of organic compounds in digested sludge-Method by measurement of the biogas production (1995).

[0140] A known volume of anaerobic sludge, (corresponding to about 10% of the sludge concentration in a real digester), suspended in an oxygen free medium, is placed in a suitable vessel leaving headspace into which any gases produced may be evolved. Prior to sealing, a small amount of test compound is added.

[0141] The vessels are incubated at constant temperature. The headspace pressure resulting from the production of gas is measured, and the DIC (dissolved inorganic carbon, this is the inorganic carbon (mainly CO2) that is dissolved in the liquid phase) content of the digesting liquid determined. From the measured values of net gas products and the net DIC formation, the extent of biodegradation is calculated. The kinetics of biodegradation may be established by taking measurements at suitable intervals during the course of the test.

[0142] The sludge used was obtained from the sewage plant in Gent (Belgium) treating domestic wastewater. Before use, the inoculum was left to stabilise during 6 days. This post-fermentation was needed to reduce the biogas production rate (background activity). After post-fermentation, the sludge was centrifuged in completely filled, sealed centrifuge tubes at approximately 2500 g for 5 minutes at room temperature. The supernatant was discarded and the sludge pellet was suspended in an oxygen-free mineral salts medium. This centrifugation-rinsing step was repeated twice. The inoculum was diluted with mineral salts medium until a final concentration of 2.5 g TS / I was obtained, which falls within the desired range of 1 to 3 g / l. The organic matter content of the test medium was 39.9% on TS. An overview of the characteristics of the diluted sludge are given in Table 8. The pH was adjusted to 7.0±0.2 with dilute mineral acid.TABLE 8Characteristics of the inoculumCharacteristicsInoculumTotal solids (TS, %)0.25Volatile solids (VS, % on TS)39.9Ash content (% on TS)60.1pH7.0

[0143] The reference and test item were analysed for total solids (TS), volatile solids (VS), and total organic carbon content (TOC). The results are given in TableTABLE 9Total solids (TS), volatile solids (VS) and total organiccarbon (TOC) content of the reference and test itemTest itemTS (%)VS (% on TS)TOC (%)Cellulose97.399.243.6Monofilament material95.696.541.3Gas Results

[0144] Pressure increase of negative control, cellulose control and test material and biogas compositions were evaluated and showed that monofilament material behaves like cellulose, some reactions with a small delay (data not shown). Table 10 shows the biogas composition after 60 days of testing. The gas compositions were within a normal range for all test vessels. The high CH4 content demonstrates that a considerable amount of CO2 was still dissolved in the liquid phase.TABLE 10Average biogas composition (%) after 60 days of testingTest seriesCO2 content (%)CH4 content (%)Control12.687.4Cellulose16.183.9Monofilament material15.085.0Biodegradation Results

[0145] Table 11 shows the biodegradation percentages of reference and test item after 60 days. They are calculated as the amount of organic carbon in the sample that was converted to gaseous carbon (CH4 and CO2, both present in the headspace and dissolved in the liquid (DIC)).TABLE 11Biodegradation percentages at the end of the test (60 days)Average CAverage CBiodegradation (%)input (mg)gaseous (mg)AVGSDRELCellulose10.17.371.910.8100.0Monofilament9.67.578.03.8108.4material

[0146] The values in Table 11 do not include the amount of carbon which was originally present in the test or reference item and which in the course of the digestion has been converted to biomass carbon. Some of the carbon that is biodegraded is indeed used for the building of new bacterial biomass. For anaerobic digestion the biomass yield factor is between 10% and 30%. This means that for 1 g of carbon consumed, between 10% and 30% is used for new cell biomass while 70% to 90% is converted to gaseous, mineral carbon under the form of CH4 or CO2.

[0147] The biodegradation result of the reference item cellulose, obtained after 60 days of testing, was 71.9%+10.8%, which means that the criterion for a valid test (ISO 11734 (1995): 60% degradation of the reference item) was met.

[0148] Tested monofilament material started to degrade after a lag-phase of about 7 days. After about 35 days, a plateau phase was obtained for all replicates. The tested material reached a biodegradation of 78.0%+3.8% (or 108.4% relative to cellulose) after 60 days. In general, a test item has demonstrated a satisfactory level of biodegradation when 90% absolute or relative biodegradation is reached. This means that the monofilament material can be considered biodegradable under aqueous mesophilic anaerobic conditions within 60 days.Conclusions

[0149] The test shows that monofilament material started to degrade after a lag-phase of about 7 days. After about 35 days, a plateau phase was obtained for all replicates. The test item reached a biodegradation of 78.0%+3.8% (or 108.4% relative to cellulose) after 60 days. The monofilament material can be considered biodegradable under aqueous mesophilic anaerobic conditions within 60 days.Example 6: Industrial Composting

[0150] The aerobic biodegradation of test item Monofilament material was evaluated by Tests for biodegradability were performed by OWS nv, Belgium in a controlled composting test at an incubation temperature of 58° C.±2° C. The test was performed in duplicate. Reference material cellulose was added as powder, while test item Monofilament material was previously reduced in size (cryogenically milled until <1 mm). At start-up 80 g of reference or test item was added to 1200 g of compost inoculum. The control reactors contained only 1200 g of inoculum. The total test duration was 45 days.

[0151] Standard followed was ISO 14855-1 Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions-Method by analysis of evolved carbon dioxide (2012), but in duplicate instead of triplicate.

[0152] The inoculum was derived from the organic fraction of municipal solid waste. The waste was stabilized and aerated in a composting bin at the laboratory under controlled conditions for more than 20 weeks. Before use the compost was sieved through 5 mm. The characteristics of the inoculum used at start are given in Table 12.

[0153] The inoculum should have a total solids (TS) content between 50% and 55% and a volatile solids content (VS) on TS of more than 30%. Moreover, the pH should be between 7.0 and 9.0. As can be seen from Table 12 these requirements were fulfilled. The inoculum showed a total solids content of 54.1%, a volatile solids content of 33.4% on TS and a pH of 7.5.

[0154] According to the norm ISO 14855-1 (2012) a CO2 production between 50 mg and 150 mg CO2 / g VS should be measured for the controls during the first 10 days of the test. After 10 days an optimal background activity of 57 mg CO2 / g VS was measured.TABLE 12Characteristics of the inoculumCharacteristicsInoculumTotal solids (TS, %)54.1Moisture content (%)45.9Volatile solids (VS, % on TS)33.4Ash content (% on TS)66.6pH7.5Electrical conductivity (EC, μS / cm)4970Volatile fatty acids (VFA, g / l)b.r.Total N (g / kg TS)17.9NH4+—N (mg / l)18.1NOx−—N (mg / l)1410C / N9

[0155] The total solids (TS), volatile solids (VS), total organic carbon content (TOC) and theoretical amount of evolved carbon dioxide (ThCO2) of the reference and test item are summarized in Table 13.TABLE 13TS, VS, TOC and ThCO2 of reference and test itemTest itemTS (%)VS (% on TS)TOC (%)ThCO2 (mg / g)Cellulose97.399.243.61599Monofilament97.096.938.41408materialBiodegradation Results

[0156] Table 14 shows the net CO2 production and the biodegradation percentage of the reference and test item at the end of the test (45 days).TABLE 14Net CO2 production and biodegradation after 45 daysNet CO2(mg / g testBiodegradation (%)Test seriesitem)AVGSDRELCellulose145991.21.5100.0Monofilament122587.07.595.3material

[0157] The biodegradation of reference item cellulose started almost immediately and proceeded at a good rate. After 12 days cellulose was already degraded by 71.5%. The biodegradation rate gradually slowed down and at the end of the test (45 days) a plateau in biodegradation was reached at a level of 91.2%+1.5%. The test is considered valid if after 45 days the biodegradation percentage of the reference item is more than 70% and if the standard deviation of the biodegradation percentage of the reference item is less than 20% at the end of the test. Both requirements were fulfilled.

[0158] The biodegradation of tested monofilament material also started almost immediately and proceeded at a good rate. After 20 days test item Monofilament material was already degraded by 69.6%. The biodegradation rate gradually slowed down and at the end of the test (45 days) a plateau in biodegradation was reached at a level of 87.0%+7.5%. On a relative basis, compared to suitable reference substrate cellulose, a biodegradation percentage of 95.3% was calculated.

[0159] Monofilament material has demonstrated a satisfactory level of biodegradation when 90% absolute or relative biodegradation is reached. The maximum allowed test duration determined by the standards on industrial composting is 180 days. It can be concluded that tested monofilament material fulfilled the 90% requirement within 45 days of testing under the given aerobic conditions.Example 7: Properties of Non-Woven

[0160] The fibrous monofilaments were formed as explained in WO 2018 / 115577. The compositions of the fibrous monofilaments were 84.6 wt.-% MCF, CMC 12 wt.-%, PAE 2 wt.-% and aPam 1.4 wt.-%.

[0161] Nonwoven comprising 40 wt.-% fibrous monofilament, 40 wt-% Lyocell and 20 wt.-% PP BiCo (polypropylene bicomponent) was formed by using Aquajet technology by Suominen Corporation, Finland. Measurements are made for dry and wet sheets.

[0162] The water retention value (WRV) characterizes the fiber's ability to retain water if defined centrifugal forces are applied by DIN 53814, so major part of liquid absorbed between the fibers is removed. The water holding capacity or imbibition value (WIV) measures the amount of liquid which is absorbed between the fibers under free swell conditions according to the European Pharmacopoeia.TABLE 15Sheet 1Sheet 3BW~35~65Oven temperature, ° C.patternBasis weight (g / m2)30.258.0Thickness dry (mm)0.430.62Thickness wet(mm)0.370.60Dry Bulk (m3 / g; mm / gsm*1000)14.210.7Wet Bulk (m3 / g; mm / gsm*1000)12.310.3Thickness reduction when wet compared to14%3%dryDensity, dry0.0700.094Density, wet0.0820.097Tensile strength MD, dry (N / 5 cm)33.382.1Tensile strength CD, dry (N / 5 cm)7.125.2Elongation MD, dry (max, %)18.620.4Elongation CD, dry (max, %)89.879.2Tensile strength MD, wet (N / 5 cm)24.778.6Tensile strength CD, wet (N / 5 cm)5.332.0Elongation MD, wet (max, %)25.926.3Elongation CD, wet (max, %)117.982.4Abs. capacity (g / g) with water11.78.7

[0163] Tensile strengths (machine direction, md and cross direction, cd) were performed both for dry (solid line) and wet (dashed line) sheets. The results are shown in FIGS. 2a and 2b (machine direction and cross direction).

[0164] In nonwoven industry, high absorbency is an important, highly demanded property in many end-uses such as diapers, tampons, sanitary napkins, medical sponges, baby wipes, wiping cloth and the like. Each of these applications require a high capacity for absorbing and retaining water and other aqueous fluids, particularly body fluids.

[0165] It was noted that water adsorption capacity of the nonwoven is excellent, even about 1000% of dry weight of the nonwoven. This property is valuable in e.g., diaper and other adsorbent applications.

Claims

1. A nonwoven fabric comprising:(a) 20 to 100 wt.-% of the total weight of the nonwoven fabric a fibrous monofilament comprising:i. 80 to 98 wt.-% of the weight of component (a) non-regenerated microfibrillated cellulose (MFC); andii. 2 to 20 wt. % of the weight of component (a) dispersion agent(s) selected from carboxymethylcellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose hydroxyethyl methyl cellulose, methyl ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl cellulose, and starch or any mixture thereof, and(b) 0 to 80 wt.-% of the total weight of the nonwoven fabric thermoplastic fibers or man-made cellulosic fibers or non-wood derived cellulosic fibers or any mixture thereof.

2. The nonwoven fabric according to claim 1, wherein the fibrous monofilament further comprises additives selected from strength additives, hydrophobic adhesives, pigment(s), and / or other modifier(s).

3. The nonwoven fabric according to claim 1, wherein the strength additive is a dry strength agent or a wet strength agent.

4. The nonwoven fabric according to claim 2, wherein the hydrophobic adhesive is selected from alkyl ketene dimer, alkenylsuccinic anhydride, rosin, natural waxes, and modified sun flower based adhesive.

5. The nonwoven fabric according to claim 2, wherein said strength additive is G-Pam in amount of 0.5 to 3 wt. % of the total weight of the fibrous monofilament.

6. The nonwoven fabric according to claim 2, wherein said strength agent is anionic polyacrylamide in amount of 0.5 to 5 wt. % of the total weight of the fibrous monofilament.

7. The nonwoven fabric according to claim 2, wherein said strength agent is PEO in an amount of 0.5 to 5 wt.-% of the total weight of the fibrous monofilament.

8. The nonwoven fabric according to claim 2, wherein the hydrophobic adhesive is alkyl ketene dimer in amount of 0.5 to 10 wt. % of the total weight of the fibrous monofilament.

9. The nonwoven fabric according to claim 1, wherein said man-made cellulosic fibers are fiber(s) is (are) selected from the list consisting of Lyocell, viscose, modal, acetate, rayon, and recycled textile waste fibers or any mixture thereof.

10. The nonwoven fabric according to claim 1, wherein said thermoplastic fibers are selected from polypropylene, polyamide, polyester, polypropylene / polyester, and bi-component short cut fibers.

11. The nonwoven fabric according to claim 1, wherein said non-wood derived cellulosic fibers are selected from cotton, hemp, flax, sisal, jute, kenaf, bamboo, peat, and coconut or a mixture thereof; such as cotton, flax, hemp or a mixture thereof.

12. The nonwoven fabric according to claim 1, wherein the fabric comprises 80 to 98 wt.-% of the weight of non-regenerated microfibrillated cellulose and 2 to 20 wt. % of dispersion agent(s).

13. A product comprising: the nonwoven fabric according to claim 1, and optionally one or more protective layers and / or supporting framework and / or adsorbed moist or chemicals and / or means for fastening the nonwoven fabric.

14. The product according to claim 13, wherein said product is a surgical mask, a filter layer or a protective curtain comprising at least one layer of the nonwoven fabric and at least one protective layer.

15. The product according to claim 13, wherein the product is an impregnated sheet of the nonwoven fabric.

16. A method for manufacturing a fibrous monofilament comprising:forming an aqueous suspension comprising 80-98 wt.-% of water and 2-20 wt.-% dry matter, wherein the dry matter comprises microfibrillated cellulose and at least one dispersion agent selected from carboxymethylcellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, methyl ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl cellulose, and starch or any mixture thereof;extruding the suspension into a monofilament; anddrying the monofilament.

17. A fibrous monofilament comprising:a. 80 to 98 wt.-% non-regenerated microfibrillated cellulose; andb. 2 to 20 wt. %) dispersion agent(s) selected from carboxymethylcellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, methyl ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl cellulose, and starch or any mixture thereof; and optionallyc. additives according to claim 2; andbased on the dry weight of the monofilament, and having a tenacity of at least 1 cN / dTex measured using standard ASTM 3822 / D3822M-14 at RH 65% (+ / −2%) and temperature 20° C. (+ / −2° C.).

18. A method for manufacturing a nonwoven fabric comprising the steps of:(a) providing a fibrous monofilament comprisingi. 80 to 98 wt.-% of the weight of component (a) non-regenerated microfibrillated cellulose; andii. 2 to 20 wt. % of the weight of component (a) dispersion agent(s) selected from carboxymethylcellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, methyl ethyl hydroxyethyl cellulose, hydroxypropyl cellulose (HPC), ethyl cellulose (EC), and starch or any mixture thereof;(b) optionally providing further fibers selected from thermobonding polymers, man-made cellulosic fibers, non-wood cellulosic fibers and any mixture thereof; and(c) depositing filaments of (a) and optional fibers of (b) in a random pattern onto a surface to form nonwoven fabric and optionally drying the formed fabric.

19. The method according to claim 18, wherein step (c) comprises carding, wet or air laying, or spun laying the deposited filaments of (a) and optional fibers of (b) to form nonwoven fabric.

20. The method according to claim 18, wherein step (c) comprises needling, hydroentangling, thermobonding or chemically bonding the formed fabric.

21. The method according to claim 18, wherein step (c) comprises impregnating, smoothening, heat-setting, drying or calibrating the formed fabric.

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