WO2023187004A1

WO2023187004A1 - A continuous filament obtained from granulated cork, process for the manufacturing of a cork-based filament, and fabric thereby obtained

Info

Publication number: WO2023187004A1
Application number: PCT/EP2023/058189
Authority: WO
Inventors: Lance Johnson
Original assignee: Pda Ecolab
Priority date: 2022-03-29
Filing date: 2023-03-29
Publication date: 2023-10-05
Also published as: FR3134120A1; FR3134120B1

Abstract

The present disclosure relates to a cork-based yarn or filament comprising : - at least one yarn, tow, monofilament or tape of natural or synthetic fiber; and - a molded outer structure coating the at least one yarn, tow, monofilament or tape, the outer structure being composed of granulated cork and/or micro-granulated cork and/or cork dust.

Description

A CONTINUOUS FILAMENT OBTAINED FROM GRANULATED CORK, PROCESS FOR THE MANUFACTURING OF A CORK-BASED FILAMENT, AND FABRIC THEREBY OBTAINED

Technical field

[0001] The present disclosure relates generally to filaments and fabrics, and in particular to filaments and fabrics containing cork.

Background art

[0002] It is known that cork is renewably obtained from the bark of some trees, in particular the cork oak, i.e. without uprooting them. Cork has many interesting properties which include impermeability to water, imputrescibility, high compressibility / elasticity, and it is also insulating. For these reasons, as well as for its effective manufacture through cutting operations, cork is used in several fields ranging from fashion to food and wine preservation to aerospace .

[0003] One common use is its reduction into thin sheets which are adhered to an adhesive linen, obtaining linenized cork sheets that can be employed, e. g., as wallpaper, upholstery, handbags and luggage, etc. These kinds of sheets, which may be as fine as a few tenths of millimeter thick often also serve as a raw material for the manufacture of cork "yarns," "stripes," or "ribbons". In instances where a yarn is created, the linenized cork sheets are most-typically cut into thin strips, and then twisted and agglomerated and/or stitched together into a yarn. Alternatively, it is known that a "ribbon" or "stripe" of linenized cork can be produced by employing a similarly thin sheet of cork which is slightly more than twice the width of the base fabric to which it will be adhered (typically 2-10mm for the fabric, and 5-21mm for the cork) , bonding the adhesive linen strip to the center of the cork, and folding the remaining material around the linen strip so that the edges meet on the opposing face to fully enclose the linen material .

[ 0004 ] Both of these processes present similar drawbacks : 1 ) The processes require finely cleaved sheets of cork to be prepared which is an expensive raw material to obtain; 2 ) The industrial process to either cut-down the large format lineni zed cork sheets , or to accurately wrap a linen strip to encompass it in cork are both extreme precision processes which increase the time and cost to manufacture ; 3 ) Because the processes are based on the use of prepared linen fabrics and strips which have a typical length ranging between 40m and 100m, it is necessary to perform additional precision steps in order to produce an apparently seamless yarn or ribbon when technical requirements demand greater lengths . The result is that cork yarns and ribbons thusly prepared can have a cost of several hundred euros per kilogram .

Summary of Invention

[ 0005 ] Embodiments of the present invention relates to a filament fabricated using granulated and micro-granulated cork which is able to be produced in extended lengths , a process for the manufacturing of such cork-based filament , and the fabrics obtained thereby .

[ 0006 ] While cork is an exceptional material for many uses , a cost which is so high puts it well beyond the acceptable price of materials for many applications where cork' s characteristics would be beneficial . One technical problem present in the prior art is to provide cork-based filament which is conceived to avoid manufacturing processes necessitating the above-cited drawbacks with reference to the state of the art . Such problem would be ef fectively addressed by a filament which can be fabricated with a process which is able to use lower-value cork as a raw material , signi ficantly reduces the orders of precision required for machinery to prepare an acceptable end-product , and is appropriate for bulk applications where a continuous filament of more than 1 000 m is reasonable without splices or j oins in the filament .

[ 0007 ] The current invention outlines a cork-based filament having at least one natural fiber "yarn" contained within its structure whereby cork granules and micro granules are adhered to both the surface of the yarn and to each other through an agglomerating process . In order to produce such a filament , a manufacturing process is envisioned comprising the steps of : * preparing granules or microgranules of cork material from trimmings/waste , inferior grade , and recycled cork sources ; * providing at least one natural fiber yarn, tow, monofilament or tape wound upon a donor bobbin; * positioning the donor bobbin at the input end of a die with at least one inj ection port and running the yarn through the die to an uptake bobbin; * preparing the cork granules or microgranules with an agglomerating agent and forcing them, under pressure , through the at least one inj ection port into the die as the tensioned yarn is taken up by the uptake bobbin at a concurrent rate to the speed of the inj ection flow filling the die cavity; * performing a heat exchange or other curing process to the agglomerating agent immediately before or immediately after the yarn and cork granule assembly exits the die ; * optionally treating the prepared cork-based filament with a si zing agent to provide increased suppleness , durability, or to promote matrix compatibility when the filament is intended for use in composites ; * drying the corkbased filament ; and *winding the finished cork-based filament , kept at tension, onto the uptake bobbin .

[ 0008 ] An advantage of the process according to embodiments of the present invention lies in obtaining a cork-based filament which retains certain key properties of cork, including its insulative and vibration damping properties yet can easily be manufactured at a fraction of the cost of comparable yarns or ribbons produced according to the state of the art .

[ 0009 ] With such features , the cork-based filaments thereby obtained are employable in composites , furniture making and other crafts , 3D printing (with the addition of an external polymer or monomer shell or plastici zing agent which surrounds the filament ) and other technical applications where current costs and dimensions for cork yarns and ribbons are prohibitive .

[ 0010 ] Embodiments of the present disclosure aim to at least partially address some or all of the needs in the prior art .

[ 0011 ] One aspect of the present disclosure consists of at least one natural or synthetic fiber yarn, tow, monofilament , or tape situated primarily within a surrounding structure of granulated or micro-granulated cork and/or cork dust where the cork component has been adhered to the natural or synthetic fiber yarn and to itsel f through an agglomeration or bonding process and where the cross-section of the resulting filament is determined by an external mold or die whereby the resulting filament is extruded or pultruded along the lengthwise axis of the natural- fiber yarn .

[ 0012 ] A "natural- fiber yarn" is any construction of vegetal , mineral , or animal fibers or filaments , either singular or in bundles which provide a tensile strength suitable for the manufacturing process described below . Examples of naturalfiber yarns include but are not limited to vegetal fibers such as cotton, linen, ramie , and other long fibers and staple fibers derived from plant-based origins which are twisted together to form a continuous multi filament yarn or thread; or man-made cellulosic fibers which are created from cellulose microfibrils which have been cleaved from the surrounding plant structure and re-combined into a staple fiber, long fiber, or continuous monofilament . Examples of mineral fiber yarns include basalt , silica, and other mineral fibers which are either spun as staple fibers , or spun as continuous filaments which may be aligned to form a yarn with little or no twist . Examples of animal fiber yarns include wool , silk, hair and serosa which are j oined together by twisting .

[ 0013 ] "Granulated and micro-granulated cork" are predominantly spherical but irregularly shaped cork particles which are achieved by a grinding or granulating process where the cork particles have a dimension of between 0 . 25 mm and 1mm for micro-granulated cork, and between 1 mm and 5 mm for granulated cork . The source of the base material which is granulated may include waste from cork punching and cutting processes to obtain high-value cork products , cork of an inferior grade not suitable for use for high-quality cork products , or sources of recycled cork such as wine-bottle stoppers .

[ 0014 ] "Cork Dust" is a byproduct of cork processing which results in particles of cork which have a dimension of less than 0 . 25 mm .

[ 0015 ] According to one embodiment a single natural or synthetic fiber yarn is coated with an even volume , or an even wall thickness , of cork particles along its length, which have been adhered to both the yarn and each other to form an integral filament of determined length without j oins or splices in the length . It should be noted that , in case the path of the yarn within the resulting cork-based filament varies , the thickness of cork particles might become uneven with respect to the yarn . However, the volume or cork particles will still remain constant or substantially constant in this case because it will be determined by the cross section of the mold or die used to shape the cork particles , minus the volume of the yarn .

[ 0016 ] According to one embodiment a single natural or synthetic fiber yarn i s coated with a variable wall thickness of cork particles along its length, which have been adhered to both the yarn and each other to form an integral filament of determined length without j oins or splices in the length .

[ 0017 ] According to one embodiment more than one natural or synthetic fiber yarn is coated with a wall thickness of cork particles along its length, which have been adhered to both the yarn and each other to form an integral filament of determined length without j oins or splices in the length .

[ 0018 ] According to one embodiment the resulting filament has a round, ovoid, or other geometric cross section which is consistent along its length .

[ 0019 ] According to one embodiment the resulting filament has a cross section which changes in shape or scale along its length .

[ 0020 ] According to one embodiment the filament may be coated with a si zing agent to alter the mechanical characteristics of the filament such as to promote cohesiveness , durability, or adhesion to a matrix i f the filament is intended for composites use ; or the filament may be treated with emollients , dyes , or other substances to alter the sensory characteristics of the filament .

[ 0021 ] According to one embodiment more than one cork-based filament may be helicoidally twisted, braided, or j oined in a similar functional manner . Moreover, the j oined filaments may be coupled to a yarn sewn longitudinally thereto , and/or si zed together, in order to improve its consistency and workability . [0022] According to one embodiment at least one cork-based filament may be helicoidally twisted with other filaments, fibers or materials, or braided, or joined in a similar functional manner. Moreover, the joined filaments may be coupled to a yarn sewn longitudinally thereto, or sized together, in order to improve its consistency and workability.

[0023] The filaments may then be utilized in the construction of woven or non-woven fabrics; may be combined with a wax or polymer to allow 3D printing; may be used in the reinforcement or damping of composite structures, or any similar function where a relatively low cost, highly-ecological , insulative, vibration damping material is preferred.

[0024] According to one aspect, there is provided a corkbased filament comprising: at least one yarn, tow, monofilament or tape of natural or synthetic fiber; and an outer structure coating the at least one yarn, tow, monofilament or tape, the outer structure being composed of granulated cork and/or micro-granulated cork and/or cork dust; and the outer structure composed of cork has a cross- sectional form which is determined by an external mold or die.

[0025] According to one embodiment, the cork-based filament has a length in excess of 100 m, and for example in excess of 1000 m.

[0026] According to one embodiment, the granulated cork, micro-granulated cork, and/or cork dust is agglomerated to itself and to the at least one yarn, tow, monofilament or tape. According to one embodiment, the granulated cork, microgranulated cork, and/or cork dust is at least partially agglomerated by natural adhesive components released from the cork itself.

[0027] According to one embodiment, the granulated cork, micro-granulated cork, and/or cork dust is at least partially agglomerated by an added agglomerating agent comprising one or more of: natural or synthetic polymers, lignins, casein, starches, resins, glues, or, for example, other bonding agents commonly used for the production of cork products.

[0028] According to one embodiment, the at least one yarn, tow, monofilament or tape has a linear density in the range 20 to 2000 Tex (g/km) , and the outer structure for example has a volume per meter which is at least equal to the volume per meter of the at least one yarn, tow, monofilament or tape, and for example equal to at least five times, or ten times, or even up to 200 times the volume per meter of the at least one yarn, tow, monofilament or tape.

[0029] According to one embodiment, the at least one yarn, tow, monofilament or tape comprises twisted or untwisted fibers formed of one or more of: natural fibers, nylon, polyester, polyethylene, polypropylene, Dyneema, aramid yarn, or other synthetic fibers, the yarn, tow, monofilament or tape for example having a breaking strength of at least 8 Newtons .

[0030] According to one embodiment, the cork-based filament has a width to thickness ratio for example in the range 1:1 to 1:20, and for example having a periodically varying thickness, width and/or shape along its length.

[0031] According to a further aspect, there is provided a 3D printing filament comprising the above cork-based filament encased in a polymer shell or plasticizing agent suitable for being activated by the 3D printing process, the plasticizing agent for example comprising a thermo-plastic, photo-reactive plastic and/or polymer medium.

[0032] According to a further aspect, there is provided a process for manufacturing a cork-based filament, the process comprising: supplying at least one natural or synthetic yarn, tow or filament to a die; and supplying, under pressure, granulated cork and/or micro-granulated cork and/or cork dust to an injection port of the die in order to form, by extrusion, an outer structure coating the at least one yarn, tow, monofilament or tape.

[0033] According to one embodiment, the process further comprises, supplying the granulated cork and/or microgranulated cork and/or cork dust to the injection port, forcing the cork granules into the die, and combining the granulated cork and/or micro-granulated cork and/or cork dust with an agglomerating agent, wherein the agglomerating agent is supplied by a separate injection port of the die and the granulated cork and/or micro-granulated cork and/or cork dust are combined with the agglomerating agent inside the die.

[0034] According to one embodiment, the process further comprises, prior to supplying the granulated cork and/or micro-granulated cork and/or cork dust to the injection port, combining the granulated cork and/or micro-granulated cork and/or cork dust with an agglomerating agent, wherein the agglomerating agent is supplied with the granulated cork and/or micro-granulated cork and/or cork dust to the injection port .

[0035] According to one embodiment, the process further comprises, supplying the granulated cork and/or microgranulated cork and/or cork dust to the die through the injection port, whereby the cork granules are situated along the outer surface of the natural fiber yarn, and once situated thusly, applying steam, for example super-heated to a temperature of between 270° C and 370°C, and for example to between 300°C and 350°C, through a separate injection port to the granulated cork and/or micro-granulated cork and/or cork dust, to bring out, for example, naturally occurring pectins, lignins and/or other chemical compounds from within the cork to serve as the agglomerating agent.

[0036] According to a further aspect, there is provided a process of forming a fabric comprising combining the above cork-based filament with other filaments and/or yarns to form the fabric.

[0037] According to yet a further aspect, there is provided a process of forming a plastic reinforced composite comprising combining the above cork-based filament with an encapsulating plastic matrix.

[0038] According to a further aspect, there is provided a process of forming a fabric comprising: manufacturing a corkbased filament according to the above process; and combining the cork-based filament with other filaments and/or yarns to form the fabric.

[0039] According to yet a further aspect, there is provided a process of forming a plastic reinforced composite comprising: manufacturing a cork-based filament according to the above process; and combining the cork-based filament with an encapsulating plastic.

[0040] Further aspects and embodiments are defined by the appended set of claims.

Brief description of drawings

[0041] Embodiments of the present invention will be described hereinbelow according to some variations of a preferred embodiment thereof, given as a non-limiting and outlining example. Reference will be made to the figures in the annexed drawings, wherein:

[0042] Figure 1A is an enlarged perspective view of a section of a cork-based filament according to an embodiment of the present disclosure; [ 0043 ] Figure IB is a cross-section view of the cork-based filament of Figure 1A;

[ 0044 ] Figure 2A is an enlarged perspective view of a section of a cork-based filament obtained according to the present process according to another embodiment of the present disclosure ;

[ 0045 ] Figure 2B is a cross-section view of the cork-based filament of Figure 2A;

[ 0046 ] Figure 3 is a schematic view of a donor bobbin, a die apparatus for agglomerating granulated cork to the at least one yarn, and an uptake bobbin which winds and stores the assembled cork-based filament according to an embodiment of the present disclosure ;

[ 0047 ] Figure 4 is a schematic view of more than one donor bobbin, an alternative die apparatus for agglomerating granulated cork to more than one yarn, and an uptake bobbin which winds and stores the assembled cork-based filament according to an embodiment of the present disclosure ; and

[ 0048 ] Figure 5 is a flow diagram illustrating operations in a method of fabricating a cork-based filament according to an example embodiment of the present disclosure .

Description of embodiments

[ 0049 ] Like features have been designated by like references in the various figures . In particular, the structural and/or functional features that are common among the various embodiments may have the same references and may dispose identical structural , dimensional and material properties .

[ 0050 ] For the sake of clarity, only the operations and elements that are useful for an understanding of the embodiments described herein have been illustrated and described in detail . [0051] Unless indicated otherwise, when reference is made to two elements connected together, this signifies a direct connection without any intermediate elements other than conductors, and when reference is made to two elements coupled together, this signifies that these two elements can be connected or they can be coupled via one or more other elements .

[0052] In the following disclosure, unless indicated otherwise, when reference is made to absolute positional qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or to relative positional qualifiers, such as the terms "above", "below", "higher", "lower", etc., or to qualifiers of orientation, such as "horizontal", "vertical", etc., reference is made to the orientation shown in the figures.

[0053] Unless specified otherwise, the expressions "around", "approximately", "substantially" and "in the order of" signify within 10 %, and preferably within 5 %.

[0054] Figure 1A is an enlarged perspective view of a section of a first embodiment of a cork-based filament 100 produced with a natural or synthetic fiber yarn, tow or monofilament 101, referred to hereafter as a yarn, contained within an outer structure 102 made of agglomerated cork, which can be obtained according to a process described herein.

[0055] Figure 2A shows an enlarged perspective view of a section of a second embodiment of a cork-based filament 200 produced with two natural or synthetic fiber yarns, tows or monofilaments 101, 201, referred to hereafter as yarns, contained within an outer structure 102 made of agglomerated cork, which can be obtained according to a process described herein . [0056] The outer structure 102 of the cork-based filaments 100, 200 of Figures 1A and 2A is for example molded, and is for example over-molded onto an outer surface of the yarn, tow or monofilament 101 and/or 201. The outer structure 102 is for example composed of granulated cork and/or microgranulated cork and/or cork dust. The outer structure 102 is for example formed by an extrusion process or co-extrusion process, a cable-coating extrusion process, or extrusion over-molding process.

[0057] "Granulated cork" and "micro-granulated cork" are for example predominantly spherical but irregularly shaped cork particles which are achieved by a grinding or granulating process where the cork particles have a dimension, for example, of between 0.25 mm and 1 mm for micro-granulated cork, and between 1 mm and 5 mm for granulated cork. The source of the base material which is granulated may include waste from cork punching and cutting processes used to obtain high-value cork products, cork of an inferior grade not suitable for use for high-quality cork products, or sources of recycled cork such as wine-bottle stoppers.

[0058] "Cork Dust" is for example a byproduct of cork processing which results in particles of cork which have a dimension of less than 0.25 mm.

[0059] As represented in Figures IB and 2B, the natural or synthetic fiber yarns 101, 201 each for example has a substantially circular cross-section. The yarns 101, 201 each for example have a diameter of at least 50 microns, and for example of at least 100 microns.

[0060] In alternative embodiments, the yarn 101 and/or 201 could be replaced by a tape 101, 201 of the same natural or synthetic fiber but having a width greater than its thickness, for example having a width to thickness ratio is equal to 2:1 or more, and in some cases equal to 200:1. For example, each of the tapes 101, 201 has a thickness of at least 50 microns, and for example of at least 100 microns, and a width of at least 100 microns and up to 10 mm. In such a case, the corkbased filaments 100, 200 will also be substantially in the form of tapes.

[0061] A tensile breaking strength of the yarns or tapes 101, 201, is for example at least equal to 8 N.

[0062] As represented in Figure IB, in some embodiments, the outer structure 102 is a coating formed on the yarn 101 having a thickness th of at least 0.1 mm, and for example at least 0.2 mm or 0.5 mm. Similarly, as represented in Figure 2B, the outer structure 102 is a coating formed on both yarns and having a thickness th of at least 0.1 mm, and for example at least 0.2 mm or 0.5 mm, with respect to either or both yarns. The outer structure 102 for example covers an entire outer surface of each of the yarns, 101, 201, between ends of the yarns 101, 201. In some embodiments, the thickness of the outer structure 102, and/or the volume of the outer structure 102, is constant, or substantially constant, along the length of the yarn or yarns. It should be noted that, in case the path of the yarn or yarns varies within the resulting corkbased filament, the thickness of cork particles might become uneven with respect to the yarn or yarns in some portions of the resulting filament. However, in this case, a volume of cork particles for example still remains constant or substantially along the length of the yarn or yarns, because it will be determined by the cross section of the mold or die used to shape the cork particles, minus the volume of the yarn or yarns .

[0063] In some embodiments, the cork-based filament 100 or 200 has a width to thickness ratio in the range 1:1 to 1:20, and for example has a periodically varying thickness, width and/or shape along its length. In the example of Figure IB, the width to thickness ratio is equal to substantially 1:1. In the example of Figure 2B, the width (horizontal direction in the figure) to thickness (vertical direction in the figure) ratio is equal to substantially 3:2.

[0064] The cork-based filament 100, 200 of Figures 1A and 2A each have, for example, a length in excess of 100 m, and for example in excess of 1000 m.

[0065] According to one embodiment, the granulated cork, micro-granulated cork, and/or cork dust is agglomerated or bonded to itself and to the at least one yarn 101 or 201. For example, the granulated cork, micro-granulated cork, and/or cork dust is at least partially agglomerated or bonded by natural adhesive components released from the cork itself. Additionally, or alternatively, the granulated cork, microgranulated cork, and/or cork dust is at least partially agglomerated or bonded by an added agglomerating agent, which may comprise one or more of: natural or synthetic polymers, lignins, casein, starches, resins, glues, or, for example, other bonding agents commonly used for the production of cork products .

[0066] In some embodiments, the yarn 101 of Figure 1A has a linear density in the range 20 to 2000 Tex (g/km) . The outer structure 102 of the filament 100 of Figure 1A for example has a volume per meter which is at least equal the volume per meter of the yarn 101, and for example equal to at least five times the volume per meter of the yarn 101, or equal to at least ten times the volume per meter of the yarn 101, and in some cases equal to up to 200 times the volume per meter of the yarn 101.

[0067] In some embodiments, the pair of yarns 101, 201 of

Figure 2A have a combined linear density in the range 20 to 2000 Tex (g/km) . The outer structure 102 of the filament 200 of Figure 2A for example has a volume per meter which is at least equal the volume per meter of the pair of yarns 101, 201, and for example equal to at least five times the volume per meter of the pair of yarns 101, 201, or equal to at least ten times the volume per meter of the pair of yarns 101, 201 and in some cases equal to up to 200 times the combined volume per meter of the pair of yarns 101, 201.

[0068] In some embodiments, the yarn 101 and/or 201 comprises twisted or untwisted fibers formed of one or more of: vegetal fibers such as cotton, linen, ramie, or man-made cellulosic fibers; mineral fibers such as basalt, silica, and other mineral fibers; animal fibers such as wool, silk, hair and serosa; or synthetic fibers such as nylon, polyester, polyethylene, polypropylene, Dyneema, or aramid fibers.

[0069] Figure 3 generally illustrates the equipment and process to produce a cork-based filament such as the corkbased filament 100 of Figure 1. A donor bobbin 10 of natural or synthetic fiber yarn 101 is positioned proximate to the input side of a die 11 for the forming of agglomerated cork. The yarn 101 is for example threaded through a stationary device 41 with an aperture which is slightly larger than the yarn 101 and which is made out of a low-friction material, to guide the yarn into the die 11, and in particular to a yarn entry port of the die 11. Examples of low-friction materials for the purposes described herein include certain polyolefins, polyamides, engineered polymers such as turcite, or low- friction metals such as brass. The yarn 101 for example passes through a tapering channel 111 of the die 11 and to a mixing point 112 where the cork particles are adhered to the yarn.

[0070] For example, cork particles 102 have been placed in a reservoir, or "hopper" 13. The cork particles 102 are for example fed through an injection port 113 of the die by a "screw feed device" 132 or similar feed device. The cork particles are for example joined with an agglomerating agent, which has for example been fed from a reservoir 141 through a second injection port 114 of the die.

[0071] The cork particles 102, agglomerating agent, and yarn 101 are for example adhered together at the mixing point 112. The reservoir or hopper 13 is for example configured to supply the cork particles under pressure, for example at a pressure that is higher than the ambient pressure, and up to 5 MPa, and for example of between 0.5 MPa and 3 MPa. Additionally, the reservoir 141 is for example configured to supply the agglomerating agent at a pressure that is higher than the ambient pressure, and up to 5 MPa, and for example of between 0.5 MPa and 3 MPa. In some cases, the pressure of the agglomerating agent is substantially the same pressure as the cork particles, whereas in other cases it is chosen to be different in order to adjust the ratio of agglomerating agent to cork particles.

[0072] As the yarn 101 continues its path through the die 11, a forming end 115 of the tapered channel 111 adds compression to the assembly of yarn, cork, and agglomerating agent to give it its final molded form. Through the forming section 115, the die may include a heating element, cooling elements, high-frequency elements for ultrasonic or radiofrequency bonding, or other appropriate devices 60 for heat and/or energy transfer to cure the agglomerating agent, cork particles, and yarn into a single cohesive filament.

[0073] Upon exit of the die 11, the cork-based filament 100 is for example passed through a second stationary device 42 with an aperture which is slightly larger than the cork-based filament 100 and which is made out of a low-friction material to maintain the filament's straight path through and out of the die 11. The filament 100 then for example passes through a second aperture 50 formed of a low-friction material, and which runs back and forth on a track or guide, which is for example parallel to the axis of rotation of the uptake bobbin 12, in order to evenly distribute the filament 100 on the uptake bobbin 12.

[0074] Figure 4 is a schematic view of more than one donor bobbin 13, an alternative die apparatus 11' for agglomerating granulated cork to more than one yarn, and an uptake bobbin 12 which winds and stores the assembled cork-based filament according to an embodiment of the present invention. For example, the apparatus of Figure 4 is used to produce a corkbased filament such as the cork-based filament 200 of Figure 2, having multiple yarns contained within.

[0075] A plurality of donor bobbins 10 & 20 supplying natural or synthetic fiber yarns 101 and 201 are positioned proximate to the input side of the die 11' for the forming of agglomerated cork. The yarns 101 & 102 are for example threaded through a stationary device 41 with a corresponding number of apertures, each aperture being slightly larger than the yarns 101 & 102, and which is made out of a low-friction material, to guide the yarns into the die 11, and in particular to a yarn entry port of the die 11. The yarns 101 & 102 pass through a tapering channel 111, similar to that of Figure 3, and to a mixing point 112, where cork particles are adhered to the yarns 101, 201.

[0076] For example, the cork particles have been pre-mixed with an agglomerating agent and placed in the reservoir, or "hopper" 13, and have been fed through an injection port 113 by a "screw feed device" 132 or similar feed device. The reservoir or hopper 13 is for example configured to supply the mixture of the cork particles and agglomerating agent under pressure, for example at a pressure that is higher than the ambient pressure, and up to 5 MPa, and for example of between 0.5 MPa and 3 MPa. In some embodiments, as represented in Figure 4, a plurality of reservoirs, or hoppers, 13 is provided, each coupled to a corresponding inj ection port of the die 11 ' , which can help to obtain an even coating of the outer structure of the filament 200 in the case of multiple yarns .

[ 0077 ] As the yarns 101 & 102 continue their path through the die 11 ' , the forming end 115 of the tapered channel 111 for example adds compression to the assembly of yarn, cork, and agglomerating agent to give it its final molded form . Through the forming section 115 , the die 11 ' for example includes a conveyor or tank-track style belt 70 , which propels the corkbased filament 200 through the die and allows the filament to be formed with a continuous or non-continuous cross-section as the agglomerating agent , cork particles , and yarn form into a single cohesive filament .

[ 0078 ] Upon exit of the die 11 ' , the cork-based filament 200 is for example passed through a si zing bath 80 , which is for example configured to coat the cork-based filament 200 with a UV protective coating, for example applied in liquid form . The cork-based filament 200 is then for example dried to help seal and coalesce the cork construction and to aid in the bonding of the cork-based filament 200 with protective coating A second stationary device 42 , with an aperture which is slightly larger than the cork-based filament 200 and which is made out of a low- friction material to maintain the filament ' s straight path through the die 11 and si zing bath 80 , is for example positioned at the side of the bath where the corkbased filament 200 exits the si zing bath 80 . The filament 200 then for example passes through a second aperture 50 formed of a low- friction material and which for example runs back and forth on a track or guide , which is for example parallel to the axis of rotation of the uptake bobbin 12 in order to evenly distribute the filament 200 on the uptake bobbin 12 . [ 0079 ] Alternative embodiments may include the use of more than one type of natural- fiber and/or synthetic- fiber yarn or tape in constructions which include more than one yarn or tape in the interior of the cork-based filament ; and/or may include the use of natural- fiber or synthetic fiber yarns or tapes which are pre-treated with adhesive agents to improve the bonding strength of the cork particles to the yarn or tape .

[ 0080 ] The cork-based filaments , once fabricated, may be combined with additional cork-based filaments , natural fibers , synthetic fibers , or other similar materials to form a fabric . Such fabric may be produced by weaving, knitting, braiding, tubular braiding, tubular knitting, or through processes where filaments and/or yarns are stitched or tangled together to form a non-woven fabric .

[ 0081 ] While figures 3 and 4 are described according to an example in which the outer structure of cork particles is formed on one or more yarns , it could equally be used to apply the outer structure of cork particles to one or more natural or synthetic fiber tapes as described in relation with Figures 1A, IB, 2A and 2B .

[ 0082 ] Figure 5 is a flow diagram illustrating operations in a method of fabricating a cork-based filament according to an example embodiment of the present disclosure .

[ 0083 ] In an operation 501 , at least one yarn, tow, monofilament or tape , such as the yarn or tape 101 of Figure 1A or the yarns or tapes 101 , 201 of Figure 2A, are supplied to a die , such as the die 11 of Figure 3 or the die 11 ' of Figure 4 . For example , they are supplied to a yarn or tape entry port of the die 11 or 11 ' .

[ 0084 ] In an operation 502 , cork dusk and/or cork granules is/are supplied, under pressure , in other words pressuri zed to a higher pressure than the atmospheric pressure, to an injection port of the die 11, which is for example a different port to the yarn or tape entry port. For example, the cork particles are a result of a process of preparing granules or microgranules of cork material from trimmings/waste, inferior grade, and/or recycled cork sources. In some embodiments, an agglomerating agent is supplied to the same injection port, mixed with the cork particles, or to a separate injection port of the die 11 or 11' , to be combined with the cork particles. In alternative embodiments, no agglomerating agent is used. Instead, the cork particles are situated along the outer surface of the natural fiber yarn or tape, and steam is applied, for example super-heated to a temperature of between 270°C and 370°C, and for example to between 300°C and 350°C, through a separate injection port of the die to the cork particles, to bring out, for example, naturally occurring pectins, lignins and/or other chemical compounds from within the cork to serve as the agglomerating agent.

[0085] In an operation 503, the outer structure of the corkbased filament is for example formed by molding or overmolding on the yarn, tape, yarns or tapes, within the die 11 or 11' . For example, the process is an extrusion process, whereby pulling each yarn or tape through a tapered, narrowing, channel of the die, and at the same time injecting the cork particles under pressure to be adhered to the yarn or tape inside the tapered channel, results in the formation of the molded outer structure of the cork-based filament. In some embodiments, the process involves performing a heat exchange or other curing process to the agglomerating agent.

[0086] In some embodiments, further operations 504 and/or 505 are optionally performed.

[0087] Operation 504 for example involves passing the corkbased filament resulting from operation 503 through a sizing bath . For example , this permits the application of a protective coating, and/or of an external polymer or monomer shell or plastici zing agent surrounding the filament , which permits the cork-based filament to be used in a 3D printing process . The plastici zing agent for example comprises a thermo-plastic, photo-reactive plastic and/or polymer medium .

[ 0088 ] Operation 506 involves winding the cork-based filament onto an uptake bobbin for storage prior to use .

[ 0089 ] Examples of uses of the cork-based filament described herein include using it to form a woven or non-woven fabric, for example by combining it with other filaments and/or yarns , or using it to form a plastic reinforced composite , which for example involves incorporating the cork-based filament into an encapsulating plastic or encapsulating plastic matrix .

[ 0090 ] Further example embodiments of the present disclosure are described by the following examples .

[ 0091 ] Example 1 : A continuous cork-based filament is constructed composing : at least one yarn, tow, or monofilament of natural fiber which is situated primarily to the interior of the resulting filament ; an outer structure which is composed of granulated and/or micro-granulated cork, and/or cork dust which has been agglomerated to the natural fiber and to itsel f .

[ 0092 ] Example 2 : The filament of Example 1 , whereby the cork component of the filament is adhered to the natural fiber component of the filament and to itsel f using superheated steam as the agglomerating agent to release and activate the natural adhesive components within the cork itsel f .

[ 0093 ] Example 3 : The filament of Example 1 , whereby the cork component of the filament is agglomerated to the natural fiber component with an added agglomerating agent which may include natural or synthetic polymers , lignin, casein, starches , resins, glues, or other bonding agents which are or may become commonly used for the production of cork products.

[0094] Example 4: A manufacturing process for the manufacturing of a cork yarn comprising the steps of:

- preparing granules or microgranules of cork material from trimmings/waste, inferior grade, and recycled cork sources;

- providing at least one natural fiber yarn, tow or filament with a breaking strength which is for example at least equal to 8 Newtons wound upon a donor bobbin;

- positioning the donor bobbin at the input end of a die with at least one injection port and running the yarn through the die to an uptake bobbin; preparing the cork granules or microgranules with an agglomerating agent and forcing them, under pressure, through the at least one injection port into the die as the tensioned yarn is taken up by the uptake bobbin at a concurrent rate to the speed of the injection flow filling the die cavity;

- performing a heat exchange or other curing process to the agglomerating agent;

- drying the cork-based filament; and

- winding the finished cork-based filament, kept at tension, onto the uptake bobbin.

[0095] Example 5: A cork yarn manufactured by the process according to any one of the previous examples.

[0096] Example 6: A fabric obtained by weaving the cork yarn (20) of the Example 5.

[0097] Example 7: The use of the fabric of Example 6 and/or of the cork yarn obtained by Example 4, in the fields of dressmaking, upholstery, coatings in general, furniture making, or plastic-reinforced composites.

[0098] Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these embodiments can be combined and other variants will readily occur to those skilled in the art . For example , it will be apparent to those skilled in the art that the use of one or more of the reservoirs 141 of Figure 3 could be applied the embodiment of Figure 4 , and/or the si zing bath and/or multiple reservoirs 113 of Figure 4 could be used with the apparatus of Figure 3 .

[ 0099 ] Additionally, while embodiments have been described in which an agglomerating agent is mixed with cork particles , in alternative embodiments , the cork component of the filament is adhered to the yarn component of the filament and to itsel f using superheated steam as the agglomerating agent to release and activate the natural adhesive components within the cork itsel f .

[ 0100 ] Furthermore , while the diagrams , processes , and descriptions envision a single cork-based filament being produced from a single machine , it is envisioned that a die may provide multiple ports for the ingress and egres s of a yarn/ filament whereby a single machine may produce more than one cork-based filament at a time as is common for volume production to those skilled in the art .

[ 0101 ] Finally, the practical implementation of the embodiments and variants described herein is within the capabilities of those skilled in the art based on the functional description provided hereinabove .

Claims

CLAIMS l. A cork-based filament comprising:

- at least one yarn, tow, monofilament or tape (101, 201) of natural or synthetic fiber; and

- a molded outer structure (102) coating the at least one yarn, tow, monofilament or tape, the outer structure being composed of granulated cork and/or micro-granulated cork and/or cork dust.

2. The cork-based filament of claim 1, wherein the outer structure (102) has been formed by an extrusion process.

3. The cork-based filament of claim 1 or 2, wherein the outer structure (102) has a thickness of at least 0.1 mm.

4. The cork-based filament of any of claims 1 to 3, wherein the outer structure (102) has a volume that is constant along the length of the cork-based filament, a crosssection form of the outer structure for example being determined by an external mold or die (11, 11' ) .

5. The cork-based filament of any of claims 1 to 4, having a length in excess of 100 m, and for example in excess of 1000 m.

6. The cork-based filament of any of claims 1 to 5, wherein the granulated cork, micro-granulated cork, and/or cork dust is agglomerated to itself and to the at least one yarn, tow, monofilament or tape (101, 102) .

7. The cork-based filament of claim 6, wherein the granulated cork, micro-granulated cork, and/or cork dust is at least partially agglomerated by natural adhesive components released from the cork itself.

8. The cork-based filament of claim 6 or 7, wherein the granulated cork, micro-granulated cork, and/or cork dust is at least partially agglomerated by an added agglomerating or bonding agent comprising one or more of: natural or synthetic polymers, lignins, casein, starches, resins, glues, or, for example, other bonding agents commonly used for the production of cork products. The cork-based filament of any of claims 1 to 8, wherein the at least one yarn, tow, monofilament or tape (101, 201) has a linear density in the range 20 to 2000 Tex (g/km) . The cork-based filament of any of claims 1 to 9, wherein the outer structure (102) has a volume per meter equal to at least five times a volume per meter of the at least one yarn, tow, monofilament or tape, and for example equal to at least ten times the volume per meter of the at least one yarn, tow, monofilament or tape. The cork-based filament of any of claims 1 to 10, wherein the at least one yarn, tow, monofilament or tape (101, 201) comprises twisted or untwisted fibers formed of one or more of: vegetal fibers such as cotton, linen, ramie, or man-made cellulosic fibers; mineral fibers such as basalt, silica, and other mineral fibers; animal fibers such as wool, silk, hair and serosa; or synthetic fibers such as nylon, polyester, polyethylene, polypropylene, Dyneema, or aramid fibers. The cork-based filament of any of claims 1 to 11, having a width to thickness ratio in the range 1:1 to 1:20, and for example having a periodically varying thickness, width and/or shape along its length. A 3D printing filament comprising the cork-based filament of any of claims 1 to 12 encased in a polymer shell or plasticizing agent suitable for being activated by the 3D printing process, the plasticizing agent for example comprising a thermo-plastic, photo-reactive plastic and/or polymer medium.

. A fabric comprising the cork-based filament of any of claims 1 to 12. . A process for manufacturing a cork-based filament (100, 200) , the process comprising:

- supplying at least one natural or synthetic yarn, tow, monofilament or tape (101, 201) to a die (11, 11' ) ;

- supplying, under pressure, granulated cork and/or microgranulated cork and/or cork dust to an injection port of the die (11, 11' ) in order to form, by extrusion, an outer structure coating the at least one yarn, tow, monofilament or tape. . The process of claim 15, further comprising, prior to supplying the granulated cork and/or micro-granulated cork and/or cork dust to the injection port, combining the granulated cork and/or micro-granulated cork and/or cork dust with an agglomerating or bonding agent, wherein the agglomerating agent is supplied with the granulated cork and/or micro-granulated cork and/or cork dust to the injection port. . The process of claim 15, further comprises, supplying the granulated cork and/or micro-granulated cork and/or cork dust to the injection port, forcing the cork granules into the die, and combining the granulated cork and/or micro-granulated cork and/or cork dust with an agglomerating or bonding agent, wherein the agglomerating agent is supplied by a separate injection port of the die and the granulated cork and/or micro-granulated cork and/or cork dust are combined with the agglomerating agent inside the die. . The process of any of claims 15 to 17, further comprising, supplying the granulated cork and/or microgranulated cork and/or cork dust to the die through the injection port, whereby the cork granules are situated along the outer surface of at least one natural or synthetic yarn, tow, monofilament or tape (101, 201) , and once situated thusly, applying steam, for example super-heated to a temperature of between 270° C and 370°C, and for example to between 300°C and 350°C, through a separate injection port to the granulated cork and/or micro-granulated cork and/or cork dust, to bring out, for example, naturally occurring pectins, lignins and/or other chemical compounds from within the cork to serve as the agglomerating agent. A process of forming a fabric comprising combining the cork-based filament of any of claims 1 to 12 with other filaments and/or yarns to form the fabric. A process of forming a plastic reinforced composite comprising incorporating the cork-based filament of any of claims 1 to 12 into an encapsulating plastic.