Fibrous monofilament, its manufacturing method, and fibrous material

Abstract

For example, a fibrous monofilament having reduced water absorption for use in textile applications is provided. The fibrous monofilament comprises at least 50% by weight of non-regenerated microfibrillated cellulose (MFC), a dispersant, at least one of a natural wax, a thermoplastic resin, a sizing agent, and a natural rubber, and a crosslinking agent. Also provided are a fibrous material comprising the same and a method for producing the fibrous monofilament.

Description

[Technical Field]

[0001] This specification relates to fibrous monofilaments, products containing the same, and methods for making the fibrous monofilaments. In particular, this specification relates to fibrous monofilaments having reduced water absorption and improved softness after several washing and drying cycles. [Background technology]

[0002] Today's textile applications often utilize synthetic materials when aiming for reduced water absorption and / or water / moisture resistance. However, synthetic materials often ultimately originate from the petroleum industry, which is one of the drivers of climate change. Therefore, there is a need for more sustainable alternatives based on natural fiber sources to be adopted in the textile industry. Natural fiber sources have been introduced to replace unsustainable cotton. However, measures are needed to reduce the water absorption of such sustainable natural fiber sources. Summary of the Invention

[0003] For example, sustainable fibrous monofilaments with reduced water absorption for use in textile applications are provided. The fibrous monofilaments disclosed herein can be used to at least partially replace petroleum-based synthetic materials currently in use. In certain applications, the disclosed fibrous monofilaments can replace unsustainable cotton. Furthermore, the production process for the fibrous monofilaments disclosed herein is environmentally friendly, utilizing mild conditions and without any harmful substances. This is a significant advantage compared to other cellulosic fibers such as viscose and lyocell. The disclosed fibrous monofilaments have reduced water absorption and improved softness after several washing and drying cycles.

[0004] According to one embodiment, a fibrous monofilament is provided, comprising at least 50% by weight of non-regenerated microfibrillated cellulose (MFC), a dispersing agent, at least one of a natural wax, a thermoplastic resin, a sizing agent, and a natural rubber, and a cross-linking agent.

[0005] According to another embodiment, there is provided a method for producing fibrous monofilaments. The method comprises forming an aqueous suspension comprising 90-96% by weight water and 4-10% by weight dry matter, the dry matter comprising non-regenerated microfibrillated cellulose (MFC), a dispersing agent, at least one of a natural wax, a thermoplastic resin, a sizing agent, and a natural rubber as an aqueous emulsion / dispersion, and a crosslinking agent, the dry matter comprising at least 50% by weight non-regenerated MFC. The method further comprises extruding the suspension into monofilaments and drying the monofilaments.

[0006] According to yet another embodiment, a fibrous material is provided, the fibrous material comprising a fibrous monofilament as described above. [Brief explanation of the drawings]

[0007] [Figure 1] Photographs illustrating a comparison of the visual appearance of a standard (non-hydrophobic) fibrous monofilament and a fibrous monofilament disclosed herein including a hydrophobic recipe and a hydrophobic surface finish are shown after three wash and dry cycles. DETAILED DESCRIPTION OF THE INVENTION

[0008] The solution is explained in more detail below with reference to several embodiments, which should not be seen as limiting.

[0009] The features recited in the described embodiments and claims are freely combinable with one another unless expressly stated otherwise.

[0010] In this disclosure, percentage values ​​relating to amounts or proportions of raw materials are weight percentages (wt %) of the dry monofilament unless otherwise indicated.

[0011] Plant materials are constructed by a matrix formed by cellulose fibers, which also contain lignin and hemicellulose. The cellulosic fibers that form such a matrix are fibril bundles, which are composed of microfibrils. Through the fibrillation process, the cellulose fibers are separated into a three-dimensional network of microfibrils with a larger surface area. These entangled fibrils are called microfibrillated cellulose (MFC). The width of the entangled fibrils in MFC can be 50 nanometers to 2 micrometers, and the length or longitudinal dimension can be 100 nanometers to 500 micrometers, for example, 100 nanometers to 200 micrometers.

[0012] In the context of the present disclosure, the method for producing MFC is not limited. MFC can be produced from cellulose fibers using methods known in the art, for example, through high pressure, high temperature, and high-speed impact homogenization. The homogenization process is used to exfoliate or disrupt the cell walls of the fibers and liberate their substructure, fibrils and microfibrils. Enzymatic and / or mechanical pretreatment of wood fibers can also be used.

[0013] In this disclosure, the expressions "non-regenerated cellulose" or "native cellulose" refer to cellulose or cellulose fibrils or fibers that have not undergone chemical or physical modification of their macromolecular structure. Non-regenerated MFC as discussed herein is substantially non-regenerated and is composed primarily of the crystalline structure of cellulose I. Cellulose I has the structure I α and I βFor example, man-made cellulosic fibers commonly used in textile applications are regenerated and their crystalline structure is primarily other than cellulose I. The conversion of cellulose I to cellulose II (or other forms such as cellulose III or cellulose IV) is irreversible. Thus, these forms are stable and cannot be converted back to cellulose I.

[0014] In the context of the present disclosure, cellulose can be derived from any plant-based material. Plant-based raw materials can be woody or non-woody. Woody materials can be based on conifers such as spruce, pine, fir, larch, Douglas fir, or hemlock, or hardwoods such as birch, aspen, poplar, alder, eucalyptus, or acacia, or any mixture of the above. Non-woody materials can be cotton, hemp, flax, sisal, jute, kenaf, bamboo, peat, or coconut. Non-woody natural cellulose fibers can be derived from agricultural residues, grasses, or other plant materials such as straw, leaves, bark, seeds, shells, flowers, vegetables, or fruits. Woody plants have good availability, a small environmental impact, and good fiber quality. The above applies to both unregenerated cellulose and also to regenerated and processed forms of cellulose.

[0015] An object of the present disclosure is to provide a sustainable natural fiber source with reduced water absorption for use in, for example, textile applications. The fibrous monofilaments disclosed herein can be used, for example, in insulation materials used in the textile industry to at least partially replace petroleum-based synthetic materials currently used. Furthermore, the disclosed fibrous monofilaments allow for the replacement of unsustainable cotton. Furthermore, the disclosed fibrous monofilaments are produced in a more environmentally friendly manner compared to other cellulosic fibers such as viscose and lyocell. The disclosed fibrous monofilaments have reduced water absorption and improved softness after several washing and drying cycles.

[0016] As used herein, the term "fibrous monofilament" refers to a continuous length of individual fibrils grouped and extending generally along the longitudinal dimension of a cellulose monofilament. The fibrils are intertwined with one another to form a permanent monofilament structure. A monofilament cannot be opened or decomposed. Disintegration of a fibrous monofilament results in only individual fibrils. A fibrous monofilament can comprise a continuous length of several meters or kilometers. The individual fibrils of a fibrous monofilament are primarily oriented along the length of the fibrous monofilament. The term "monofilament" refers to a single-strand filament produced by extruding a polymer suspension. A fibrous monofilament may also be referred to as a monofilament fiber.

[0017] The fibrous monofilament according to the present disclosure comprises or consists of non-regenerated microfibrillated cellulose (MFC), a dispersant, a cross-linking agent, and at least one of natural waxes, thermoplastics, sizing agents, and natural rubber.

[0018] According to one embodiment, the dispersant, natural wax, thermoplastic resin, sizing agent, natural rubber, and / or crosslinking agent are biobased and / or biodegradable. When the components of the fibrous monofilament are biobased and / or biodegradable, the biodegradability of the fibrous monofilament and materials prepared therefrom can be improved. Biodegradability of a material means that more than 90% of the original material is converted into CO2, water, and minerals by biological processes within six months.

[0019] The fibrous monofilament disclosed herein comprises at least 50 wt% of non-regenerated MFC based on the dry weight of the fibrous monofilament. Preferably, the amount of non-regenerated MFC is 50-95 wt%. For example, the amount of non-regenerated MFC in the fibrous monofilament can be 60-95 wt%, 70-95 wt%, 80-95 wt%, 80-90 wt%, or 80-85 wt%.

[0020] Dispersants are required in the manufacturing process of fibrous monofilaments to improve separation of MFC fibrils and prevent their settling or aggregation. The dispersant can be any anionic hydrophilic polymer. In one example, the dispersant is carboxymethyl cellulose (CMC) and / or anionic polyacrylamide (aPAM). Alternatively, the dispersant can be any of 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 combination thereof. The dispersant can also have an effect on the shear strength of the fibrous monofilaments. aPAM can also function as a rheology modifier.

[0021] MFC fibrils exhibit extensive hydrogen bonding resulting from the presence of surface hydroxyl groups. However, these hydroxyl groups also efficiently bind water molecules, thereby increasing moisture sensitivity and reducing the wet strength of materials containing MFC. To reduce moisture sensitivity of hydrophilic MFC, a degree of hydrophobicity can be added by incorporating a hydrophobic component. In the context of the present disclosure, hydrophobicity is introduced with at least one of natural waxes, thermoplastic resins, sizing agents, and natural rubbers.

[0022] The fibrous monofilament includes at least one of a natural wax, a thermoplastic resin, a size, and a natural rubber.

[0023] Thermoplastics or thermoplastics (materials) refer to polymeric materials that become soft or moldable at elevated temperatures and solidify upon cooling.

[0024] Waxes include a diverse class of lipophilic organic compounds that are plastic solids at or near ambient temperatures. Waxes typically contain higher alkanes and lipids, with melting points above about 40°C. Waxes melt to form low-viscosity liquids. Natural waxes refer to waxes produced by plants or animals. Natural waxes also include modified plant and animal waxes.

[0025] Sizing agents are substances that can be used in the textile or paper industry to adjust the absorbent and abrasive properties of a product.

[0026] Natural rubber is composed of a polymer of isoprene, along with minor impurities of other organic compounds. Natural rubber can be harvested from rubber trees or other trees in the form of latex, which is then refined into rubber. Natural rubber has high elongation and high elasticity, as well as waterproof properties.

[0027] According to one embodiment, the amount of natural wax, thermoplastic resin, sizing agent, and / or natural rubber is 0.1 to 15 wt % of the dry weight of the fibrous monofilament, for example, 0.1 to 10 wt %, 0.1 to 5 wt %, 0.5 to 5 wt %, 1 to 5 wt %, or 1 to 2.5 wt %. The effect of the natural wax, thermoplastic resin, sizing agent, and / or natural rubber is to reduce the water absorption of the fibrous monofilament.

[0028] During the manufacturing process, natural wax, thermoplastic resin, sizing agent, and / or natural rubber are added to the suspension as an aqueous emulsion. The aqueous emulsion containing natural wax, thermoplastic resin, sizing agent, and / or natural rubber may also be referred to as an aqueous dispersion. The aqueous emulsion includes an emulsion stabilizer. The emulsion stabilizer may also be referred to as an emulsifier. The emulsion stabilizer stabilizes the emulsion by reducing interfacial tension. Examples of emulsion stabilizers include surfactants and solid particles such as lignin nanoparticles. Lignin nanoparticles may be utilized as a stabilizer via the so-called Pickering emulsion strategy. Herein, the Pickering emulsion strategy may enable uniform dispersion of natural wax, thermoplastic resin, sizing agent, and / or natural rubber on the MFC network.

[0029] An example of a suitable sizing agent for the fibrous monofilaments disclosed herein is alkylketene dimer (AKD), which, in addition to reducing the water absorption properties of the fibrous monofilaments, can further increase the strength of the fibrous monofilaments.

[0030] Examples of suitable thermoplastic resins for the fibrous monofilaments disclosed herein include, for example, polybutylene adipate terephthalate (PBAT) and poly(butylene succinate-co-butylene adipate) (PBSA). Additionally, thermoplastic natural rubber, which refers to a thermoplastic material produced by blending thermoplastic rubber with natural rubber, may also be considered. Furthermore, PBAT blended with polylactic acid (PLA) may also be used.

[0031] Examples of suitable natural waxes for the fibrous monofilaments disclosed herein include, for example, beeswax, carnauba wax, and rice bran wax.

[0032] The hydrophobicity introduced by at least one of the natural wax, thermoplastic resin, sizing agent, and natural rubber has the effect of reducing the inter- and intramolecular hydrogen bonding of the MFC, thereby providing water repellency and allowing the fibrous monofilament to maintain its soft and fluffy appearance when dried after wetting.

[0033] The fibrous monofilament includes a crosslinking agent, e.g., a wet strength agent. According to one embodiment, the amount of crosslinking agent is 1 to 6 wt %, e.g., 2 to 5 wt %, of the dry weight of the fibrous monofilament. In one example, the crosslinking agent is a polyamidoamine-epichlorohydrin (PAE) resin. The PAE provides the fibrous monofilament with improved wet strength properties, such as wet strength and elongation. The PAE may also prevent shrinkage and improve wet abrasion resistance.

[0034] According to one embodiment, the fibrous monofilament further comprises an amino-functional component such as chitosan. The amino-functional component refers to a (polymeric) component having one or more free amino groups. Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). Chitosan is commercially available by deacetylating chitin, a structural component in the exoskeleton of crustaceans and the cell walls of fungi. The degree of deacetylation (%DD) in commercially available chitosan ranges from 60% to 100%. Chitosan has the effect of reducing water absorption. Furthermore, it also allows the fibrous monofilament to maintain its fluffiness after washing and subsequent drying. The amount of the amino-functional component such as chitosan can be, for example, 0.5 to 5 wt %, e.g., 1 to 3 wt %, of the dry weight of the fibrous monofilament.

[0035] Fibrous monofilaments comprising, in addition to non-regenerated MFC, a dispersant, at least one of a natural wax, a thermoplastic resin, a size, and a natural rubber, and a crosslinking agent, exhibit reduced water absorption that may be sufficient for certain applications. However, in applications where even lower water absorption is desired, the fibrous monofilaments may further comprise a hydrophobic surface finish.

[0036] For example, the hydrophobic surface finish may be a fluorine-free agent, such as a silicone-based agent or a long-chain hydrocarbon. In the context of this disclosure, a long-chain hydrocarbon refers to a hydrocarbon having at least 10 carbon atoms. The hydrophobic surface finish may be bio-based and / or biodegradable.

[0037] According to an exemplary embodiment, the fibrous monofilament comprises at least 50% by weight of non-regenerated microfibrillated cellulose, CMC as a dispersing agent, PAE resin as a cross-linking agent, and AKD.

[0038] In addition to the dispersant and cross-linking agent, the fibrous monofilament may include additional polymeric additive(s). For example, the fibrous monofilament may include a plasticizer. The plasticizer may be, for example, polyethylene oxide (PEO).

[0039] According to one embodiment, the fibrous monofilament disclosed herein exhibits a water absorption (Wa) of at most 200%, or at most 150%, or at most 100%, as measured according to EN 13543-2001. At best, a water absorption of about 50% can be achieved. The water absorption test determines the water absorption capacity of a (filled) material when immersed in water for 1 hour under specific conditions detailed in EN 13543-2001. For natural fiber-based materials, a water absorption of at most 200% is considered good, and a water absorption of at most 100% is considered very good. For reference, synthetic polyester fiber-based materials may have a water absorption of about 50%.

[0040] The fibrous monofilament according to the present disclosure has a melting point of 500 to 2000 kg / m 3, e.g., 1000 to 1700 kg / m 3 , for example, about 1500 kg / m 3 The density may be

[0041] To produce fibrous monofilaments, an aqueous suspension is formed containing water, non-regenerated microfibrillated cellulose (MFC), a dispersant, at least one of natural wax, thermoplastic resin, sizing agent, and natural rubber, and a crosslinking agent. The natural wax, thermoplastic resin, sizing agent, and / or natural rubber are added to the suspension as an aqueous emulsion / dispersion. The aqueous emulsion / dispersion also contains an emulsion stabilizer. The aqueous suspension contains 90-96% by weight water and 4-10% by weight dry matter, the dry matter comprising non-regenerated microfibrillated cellulose (MFC), a dispersant, at least one of natural wax, thermoplastic resin, sizing agent, and natural rubber, and a crosslinking agent. At least 50% by weight of the dry matter content is non-regenerated MFC.

[0042] The typical order of adding the ingredients (added to the aqueous solution) to form the aqueous suspension is MFC, crosslinker, dispersant, and at least one of natural wax, thermoplastic resin, size, and natural rubber as an aqueous emulsion / dispersion. Alternatively, the dispersant can be added immediately after the MFC.

[0043] The aqueous suspension is directed (extruded) through a small nozzle where the fibers are well aligned (oriented) with the flow. The nozzle delivers the aqueous suspension to a solid surface, which is subsequently dried to obtain fibrous monofilaments.

[0044] Initial fibril orientation of the fibrous monofilament can be achieved during the extrusion stage. A nozzle having an outer diameter equal to or less than the maximum fibril length of the fiber causes the fibrils to be substantially oriented in the longitudinal direction of the suspension exiting the nozzle. Fibril orientation along the longitudinal direction of the fibrous monofilament provides strength to the filament.

[0045] The produced fibrous monofilaments are continuous, but can be post-processed into shorter lengths by any suitable method known in the art. The thickness of the fibrous monofilaments can be influenced, at least in part, by adapting the production speed, aqueous suspension concentration, and nozzle geometry.

[0046] Maintaining an optimal pH in the suspension can play a role in the manufacturing process. The addition of PAE often strongly affects the suspension pH. For example, adding 2 wt. % PAE can lower the pH by one unit (e.g., from pH 6.5 to pH 5.5). For AKD, the optimal operating range in terms of pH is from about 6.5 to strongly alkaline. Therefore, when using PAE and AKD, it is recommended to adjust the pH of the suspension to the desired level after adding the PAE and before adding the AKD. The pH can be adjusted with a base such as NaOH. Alternatively, a buffer solution can be utilized to maintain the pH at the desired level.

[0047] The method may further include applying a hydrophobic surface finish to the monofilament after drying. The hydrophobic surface finish may be applied, for example, by at least one of plasma coating, wet spray coating, dipping, impregnation, immersion, and / or kiss roller coating. As previously mentioned, the hydrophobic surface finish may be a fluorine-free agent, such as a silicone-based agent or a long-chain hydrocarbon. The hydrophobic surface finish typically has a positive effect on the wash durability of the fibrous monofilament. The hydrophobic surface finish may be referred to as a durable water repellent (DWR). In certain cases, the hydrophobic surface finish may be arranged to be attached to the fibrous monofilament via a covalent bond. The covalent bond may attach the hydrophobic surface finish in a wash-resistant manner.

[0048] The fibrous monofilaments according to the present disclosure are utilized in fibrous materials such as woven, knitted, or nonwoven materials, or as composite materials. The fibrous monofilaments can be utilized to produce fibers or yarns for fibrous materials.

[0049] The fibrous material may be manufactured by using any method known in the art, for example, for nonwoven materials for use in thermal insulation applications in the textile industry, fibrous monofilaments may be processed into fluffy spherical clusters of material.

[0050] Textile product applications, such as clothing or sleeping bags for cold or cool environments, typically employ insulating materials. Today, when selecting an insulating material, the primary choice is between down and synthetic fillers. Down's excellent compressibility allows for small pack sizes. Down is also highly resilient. However, if the product becomes wet, down will lose its insulating power. Synthetic fillers are made with synthetic materials designed to mimic the functionality of down. Synthetic insulation is not damaged by moisture. Furthermore, synthetic fillers are much easier to maintain than down and are more cost-effective. However, as already mentioned, a drawback of synthetic materials is that they are often ultimately derived from the oil industry, one of the drivers of climate change.

[0051] The fibrous monofilaments disclosed herein exhibit reduced water absorption compared to previously used standard (non-hydrophobic) recipes. Furthermore, the presence of compacted structures after wetting in materials prepared from the monofilaments is reduced. The materials remain fluffy and flexible after drying, making them suitable for use as insulating materials, for example, in clothing. The fibrous monofilaments disclosed herein and / or materials prepared therefrom can be used to replace synthetic polyester or polypropylene fibers currently used in insulating materials. At least 50% by weight of the polyester / polypropylene fibers can be replaced with the fibrous monofilaments disclosed herein and / or materials prepared therefrom.

[0052] The way a garment interacts with a user's body plays a major role in the user's perceived comfort, particularly with regard to heat and moisture dissipation. The fibrous monofilaments disclosed herein can be used in products that can improve a user's sensory and thermal comfort. For example, the fibrous monofilaments disclosed herein can be used to provide breathability to products utilizing them. Breathability refers to the ability to dissipate heat and prevent the accumulation of water vapor (sweat), thereby providing a greater sense of comfort to the user. Furthermore, the thermal properties of fibrous monofilaments according to the present disclosure have been shown to be superior. Fibrous monofilaments produced by extruding a polymer suspension can retain a significant amount of trapped air, thus providing greater thermal insulation. Materials comprising or composed of the fibrous monofilaments disclosed herein can be used to maintain a balance between heat loss from a user's body and internal heat generation to keep the user comfortable.

[0053] The wash durability of materials comprising or consisting of the monofilaments disclosed herein has been tested by following standard ISO 6330 using a wash program at 40° C. Based on the results, the water absorption rate, and therefore the voluminous structure and flexibility of the material, can remain at a desired level over at least three wash and dry cycles.

[0054] FIG. 1 shows a photograph illustrating the comparison of the visual appearance of 3 g of a standard (non-hydrophobic) fibrous monofilament and 3 g of a fibrous monofilament disclosed herein with a hydrophobic recipe and hydrophobic surface finish after three wash and dry cycles. It can be clearly seen that the standard non-hydrophobic recipe results in a compressed, non-fluffy, paper-like structure after three wash and dry cycles. The presence of such a compressed structure is undesirable, for example, in insulation applications, because insulating capacity is lost when the material no longer exists in a fluffed, voluminous state that can trap air within the structure. Furthermore, such a compressed structure can reduce or even eliminate the flexibility of the material, thereby affecting user comfort. Fill power is a measure of a material's "fluffiness," loosely related to its insulating value. The higher the fill power, the more air a specific weight of material can trap, and therefore the greater the insulating capacity the material will have. Any insulating material provides warmth by trapping a layer of air that separates the cold side from the hot side. A thicker layer of trapped air provides greater insulation. This thickness can be referred to as "loft." After three wash and dry cycles, materials constructed from fibrous monofilaments according to the present disclosure still have a fluffy, voluminous structure, and the flexibility of the material remains, thus demonstrating desirable wash durability. [Example]

[0055] Exemplary fibrous monofilaments were prepared and their water absorption properties were investigated.

[0056] The fibrous monofilaments contained 80-85 wt% non-regenerated MFC as the main component. The non-regenerated MFC had a hemicellulose content of about 1-5 wt% or about 12-17 wt%. The fibrous monofilaments contained 1, 1.5, or 5 wt% AKD and 2 or 4 wt% PAE. CMC was used as a dispersant, and aPAM was used as a rheology modifier.

[0057] The water absorption (Wa) of (fibrous) materials containing or composed of fibrous monofilaments was measured according to EN 13543-2001. For the monofilaments described above, average water absorption was shown to be between about 50% and about 200%, depending on both the hemicellulose content of the MFC and the drying conditions of the fibrous monofilament. For reference, fibrous monofilaments prepared with a standard recipe containing 0.5 wt.% AKD and 2 wt.% PAE exhibited average water absorptions of greater than 200%, such as between about 250% and about 850%, depending on both the chemical properties, such as the hemicellulose content, of the MFC and the drying conditions of the fibrous monofilament. In general, higher water absorption values ​​were observed for fibrous monofilaments containing MFC with a higher hemicellulose content.

[0058] Furthermore, the effect of chitosan on the water absorption of (fiber) materials containing or consisting of fibrous monofilaments was investigated. The monofilament compositions and the measured average water absorption of the investigated materials are shown in Table 1. [Table 1]

[0059] All of the samples S1-S5 contained 80-85 wt% non-regenerated MFC with a hemicellulose content of approximately 12-17 wt%. Additionally, the samples contained 2 wt% or 3 wt% aPAM.

[0060] For reference, a standard recipe utilizing 0.5 wt% AKD with MFC having a hemicellulose content of approximately 12-17 wt% demonstrated an average water absorption rate of approximately 650-850%. With the addition of 1 wt% chitosan, the average water absorption rate was only approximately 300%. Therefore, the results demonstrate that chitosan, even at low concentrations, along with AKD, can reduce water absorption.

[0061] With regard to AKD, experiments have shown that an amount of 0.5 wt% AKD alone is not sufficient to reduce water absorption to the desired level, however, when combined with a hydrophobic surface finish, an amount of 0.5 wt% AKD is shown to be sufficient.

Claims

1. A fibrous monofilament, at least 50% by weight of non-regenerated microfibrillated cellulose (MFC), - a dispersant, at least one of natural waxes, thermoplastic resins, sizes, and natural rubbers; - a cross-linking agent.

2. 10. The fibrous monofilament of claim 1, wherein the dispersant, the natural wax, the thermoplastic resin, the sizing agent, the natural rubber, and / or the crosslinking agent are bio-based and / or biodegradable.

3. 3. The fibrous monofilament according to claim 1 or 2, wherein the sizing agent is alkylketene dimer (AKD).

4. The fibrous monofilament according to any one of claims 1 to 3, wherein the amount of the natural wax, thermoplastic resin, sizing agent, and / or natural rubber is 0.1 to 15% by weight.

5. 10. The fibrous monofilament according to any one of the preceding claims, wherein the amount of cross-linking agent is 1 to 6% by weight.

6. 10. The fibrous monofilament according to any one of the preceding claims, wherein the cross-linking agent is a polyamidoamine-epichlorohydrin (PAE) resin.

7. 10. A fibrous monofilament according to any one of the preceding claims, further comprising an amino-functional component such as chitosan.

8. 10. The fibrous monofilament according to any one of the preceding claims, further comprising a hydrophobic surface finish.

9. 9. The fibrous monofilament of claim 8, wherein the hydrophobic surface finish is bio-based and / or biodegradable.

10. 10. The fibrous monofilament of claim 8 or 9, wherein the hydrophobic surface finish is a fluorine-free silicone-based agent or a fluorine-free long-chain hydrocarbon.

11. 10. Fibrous monofilament according to any one of the preceding claims, exhibiting a water absorption (Wa) of at most 200%, measured according to EN 13543-2001.

12. 12. A method for producing a fibrous monofilament according to any one of claims 1 to 11, said method comprising: forming an aqueous suspension comprising 90-96% by weight of water and 4-10% by weight of dry matter, the dry matter comprising non-regenerated microfibrillated cellulose (MFC), a dispersant, at least one of a natural wax, a thermoplastic resin, a size, a natural rubber as an aqueous emulsion / dispersion, and a crosslinker, the dry matter comprising at least 50% by weight of non-regenerated MFC; - extruding said suspension into monofilaments; - drying said monofilaments.

13. The method of claim 12, further comprising applying a hydrophobic surface finish to the monofilaments after drying.

14. 14. The method of claim 13, wherein the hydrophobic surface finish is applied by at least one of plasma coating, wet spray coating, dipping, impregnation, immersion, and / or kiss roller coating.

15. A fibrous material comprising the fibrous monofilament according to any one of claims 1 to 11.

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