Recyclable threads and textiles made therefrom

Abstract

The present disclosure relates to a high strength, biodegradable and fully recyclable thread having a structure comprising a core and a skin formed from artificial cellulose fibers. Further, the present disclosure relates to a method of forming the fully recyclable wire, the method comprising providing a wire core, a wire sheath, stacking the wire sheath around the wire core; and twisting the stacked wire skin and wire core together. The present disclosure provides a line that enables circular economy, enhances sustainability, reduces textile waste, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention generally relates to high-strength recyclable threads and fabrics made therefrom, and more particularly to high-strength, biodegradable and fully recyclable threads having such a structure including a core and a sheath, which enable a circular economy of articles made therefrom to enhance sustainability and reduce textile waste. Background Art

[0002] Current systems for producing, distributing, and disposing of clothing exist almost entirely in a linear "take-make-dispose" mode, that is, extracting virgin resources, using clothing for a short period of time, and then discarding it, whereby the materials are sent to landfills or incinerated. In fact, more than 70% of discarded clothing ends up in landfills or incinerators, while less than 1% is incorporated into the production of new textiles. From this perspective, the disposal rate is equivalent to landfilling one garbage truck of textile waste per second. This problem is exacerbated by the fact that more than half of the textiles currently produced are made of synthetic fibers (which are generally non-biodegradable and have been found to shed microfibers into the surrounding environment).

[0003] The recycling of textile waste that does occur involves sending the waste to other industries for use in lower-value applications such as insulation materials, mattress fillings, and industrial wipes. The absolute amount of textile waste generated is further increased due to the underutilization of clothing. For example, the emergence of fast fashion and falling costs means that clothing production has doubled from 2000 to 2014. In today's trend-driven system, consumers keep clothing for approximately half the time they did 15 years ago. It is estimated that more than half of the fast fashion items produced are discarded within a year, leading to an extreme throwaway culture. The result of all the prominent aggregating factors is a large amount of non-reusable textile waste, which ultimately ends up in landfills or incinerators at a high environmental cost.

[0004] To achieve suitable material properties such as strength and durability, many textiles are formed of or include non-recyclable materials. For example, many garments are made of cotton with at least 2% nylon, making the garments non-recyclable.

[0005] Man-made cellulose fibers (MMCF) are a group of fibers that are typically sourced mainly from wood and, in some cases, from other cellulose sources such as bamboo or other plant materials. Cellulose exists in the plant cell wall and helps plants and trees stay upright. It is also a key component of cotton fibers, where it is found in a highly pure form. Cotton is an example of a 'natural' cellulose fiber and is processed differently from MMCF, which follows a dissolution and extrusion process and is thus referred to as'man-made'. In most MMCF production, wood is mechanically chopped and then processed multiple times into sheets of cellulose 'pulp'. These sheets are then dissolved to form a viscose solution, which is extruded through a spinneret into fibers in a wet spinning process.

[0006] From a sustainability perspective, MMCF production has great potential; moving production away from oil-derived synthetic fibers and reducing freshwater consumption by reducing cotton cultivation. In addition, MMCF uses significantly less land compared to cotton and has no pesticides or insecticides. However, crucial to the proof of sustainability are responsible sourcing practices and production processes, such as replanting forests at a faster rate than harvesting and recycling the chemicals used in production in a closed-loop manner.

[0007] At the core of the proof of sustainability of MMCF are responsible sourcing practices and production processes; ensuring that tree harvesting is done at a replenishable rate and using a closed-loop process. Despite improvements, the environmental organization Canopy estimates that around one-third of MMCF is produced from ancient and endangered forests, which poses a serious threat to the environment and our ecosystem. In addition, on the demand side, the fashion system into which MMCF enters is premised on a linear system; extracting virgin resources for production and discarding textiles after minimal use, which generates large amounts of waste.

[0008] Progress has been made in laying out a future system that is recyclable and replaces the use of virgin wood from ancient and endangered forests with responsible forestry and alternative fiber sources, namely waste cotton textiles and other agricultural residues. Cotton textiles provide an excellent source of cellulose that will be recycled into new MMCF fibers, requiring only 1 ton of cotton waste input to produce 1 ton of MMCF output compared to 2.5 to 3 tons of conventional wood input. This opportunity is unique and should not be underestimated; as long as 25% of cotton and rayon textile waste is converted into recycled MMCF, the demand for virgin wood fibers in viscose production will be eliminated.

[0009] Textile recycling technologies offer an encouraging solution to close the loop in MMCF production, thus alleviating the burden on virgin resources and reducing textile waste. There are two key forms of textile recycling: mechanical and chemical. Mechanical recycling is a more established industry, with its roots in the 'downcycling' industry, which produces materials for insulation, industrial clothing, or other low-value uses. Mechanical recycling from textiles to new textiles is typically carried out on high-purity, long staple fibers such as wool and cashmere. The mechanical recycling process involves decomposing garments by cutting them into pieces, pulling apart the fibers, and then using a carding process to untangle and align them. Inherent in the mechanical recycling process is the shortening of the fibers, which reduces their performance during yarn and fabric production. This makes it challenging to achieve the versatility and quality required for finished garments using mechanically recycled fibers. Therefore, it can be said that, given the continuous deterioration of fiber length in each cycle, the mechanical recycling of cotton does not provide a 'true circular' solution. To address this issue, recycled cotton fibers are typically blended with virgin cotton fibers to improve performance, but this worsens the environmental footprint of the final output.

[0010] Furthermore, textile-to-textile mechanical recycling solutions require high-purity raw materials. Given the prevalence of blended fabrics in the post-consumer waste stream (a study from the Netherlands estimates it to be approximately 40% of post-consumer textiles), the low tolerance for contamination by other fibers is particularly problematic. Finally, given that mechanical recycling does not change the color of the garments, they must be sorted manually into color groups, which increases the labor costs of the process. Given all of the above, it can be said that textile-to-textile mechanical recycling has greater applicability to the post-industrial (rather than post-consumer) textile waste stream, thereby better ensuring the uniformity of the raw materials in terms of purity and color.

[0011] On the other hand, chemical recycling of textile waste offers an encouraging alternative as it is able to overcome some of the drawbacks of mechanical recycling. From a process perspective, chemical recycling breaks down fibers into their chemical structural units and then rebuilds them into new fibers that are indistinguishable or even of better quality. Emerging chemical recycling technologies are also able to address the issue of blended fiber garments. For example, polyester and cotton have very different solubility characteristics, allowing chemical recycling to separate and extract the two fibers in a polycotton blend. Specifically, for cotton, which accounts for nearly a quarter of the global fiber market, the process typically involves dissolving cotton cellulose in a solvent and then wet-spinning new fibers from the resulting slurry in a manner similar to the conventional viscose process and other artificial cellulose fibers.

[0012] While this technology holds great potential in closing the loop on many textile waste materials, there are still some key obstacles to scaling it up. First, aside from a few examples, investors have not shown strong interest in this area, and given the high capital costs and long commercialization times, such investments are considered too risky. Additionally, due to the lack of formal brand interaction with innovators, the perceived risk of this technology is increased, and overall there are few underwriting agreements and other co-development contracts. Without signals of underwriting demand, it is challenging to attract investors to this area.

[0013] Therefore, there is a need for a high-strength, biodegradable, and recyclable thread that enables a circular economy for the items made from it, to enhance sustainability and reduce textile waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the claims at the end of the specification. The foregoing and other objects, features, and advantages of the present invention are apparent from the following detailed description in conjunction with the accompanying drawings, in which:

[0015] Figure 1A is a perspective schematic view of a fully recyclable thread according to an embodiment of the present invention;

[0016] Figure 1B is a cross-sectional schematic view of a fully recyclable thread according to an embodiment of the present invention;

[0017] Figure 1C is a partially cut-away perspective view of a fully recyclable thread according to an embodiment of the present invention;

[0018] Figure 2 is an SEM image of a cross-section of an embodiment of a fully recyclable thread at 250x resolution;

[0019] Figure 3 is an SEM image of a cross-section of an embodiment of a fully recyclable thread at 500x resolution;

[0020] Figure 4 is an SEM image of a cross-section of an embodiment of a fully recyclable thread at 1000x resolution;

[0021] Figure 5 is an SEM image of a cross-section of a single thread of a fully recyclable thread at 1000x resolution;

[0022] Figure 6 is an SEM image of a cross-section of a single thread of a fully recyclable thread at 1000x resolution;

[0023] Figure 7 is a SEM image along the longitudinal axis of an embodiment of a composite wire at 100x resolution; and

[0024] Figure 8 is a SEM image along the longitudinal axis of an embodiment of a composite wire at 250x resolution. Detailed Description

[0025] The present invention has use as a high-strength, biodegradable, and fully recyclable wire having a structure including a core and a sheath, which enables a circular economy for articles made therefrom to enhance sustainability and reduce textile waste.

[0026] The present invention will now be described with reference to the following embodiments. From these descriptions, it will be apparent that the present invention can be implemented in different forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the present invention to those skilled in the art. For example, features shown for one embodiment can be incorporated into other embodiments, and features shown for a particular embodiment can be deleted from other embodiments. Additionally, various changes and additions to the embodiments presented herein will be apparent to those skilled in the art in accordance with this disclosure, and these changes and additions do not depart from the present invention. Accordingly, the following description is intended to illustrate some specific embodiments of the present invention and not to exhaustively specify all of its permutations, combinations, and variations.

[0027] It should be understood that in providing a numerical range, the range is intended to cover not only the end-point values of the range but also the intermediate values, which are expressly included within the range and vary according to the last significant digit of the range. By way of example, the recited range of 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the description of the present invention are used herein only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] Unless otherwise indicated, either expressly or by context, the following terms are used herein as described below.

[0030] As used in the description of the present invention and the appended claims, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" are also intended to include the plural forms.

[0031] Also as used herein, "and / or" means and encompasses any and all possible combinations of one or more of the associated listed items, as well as the absence of a combination when interpreted in the alternative ("or").

[0032] According to an embodiment, a high-strength, biodegradable, and fully recyclable thread is provided for forming textiles made therefrom. As Figure 1A shown, an embodiment of the fully recyclable thread 10 is formed by a core 12 and a sheath 14 surrounding the core 12. According to an inventive embodiment, both the core 12 and the sheath 14 are formed of man-made cellulose fibers (MMCF).

[0033] According to some inventive embodiments, the MMCF is lyocell. Lyocell fibers are short fibers produced from natural cellulose in harvested wood pulp using a fully recyclable solvent spinning technique. These are man-made fibers, but the source is natural. Lyocell is versatile and combines excellent strength, washability, and low fabric shrinkage with all the benefits of the excellent hand, drape, color strength, luster, absorbency, and biodegradability typically associated with cellulose. It is twisted or spun into yarns and woven or knitted into fabrics or garments. According to an embodiment, the lyocell fibers are short fibers produced from natural cellulose in harvested wood pulp using a fully recyclable solvent spinning technique. Lyocell fibers are versatile and combine excellent strength, washability, and low fabric shrinkage with all the benefits of the excellent hand, drape, color strength, luster, absorbency, and biodegradability typically associated with cellulose. Lyocell can include a peach skin finish and feel and a soft powdery surface, which is light reflected from small hairs on the fabric surface, or the fiber can be silky, smooth, and shiny. When used in woven and knitted fabrics, lyocell fibers have excellent dye absorption and color stability, extremely high tensile strength in woven and knitted fabrics, very good washability, and clear stitch construction. These lyocell fibers have a linear density (dtex) of 1.7, a tenacity (cN / tex) of 42 - 44, an elongation % of 14 - 16, a wet tenacity (cN / tex) of 37 - 41, a wet elongation % of 16 - 18, a 5% elongation wet modulus (cN / tex) of 270, and a water absorbency % of 65. According to an embodiment, the lyocell includes native cellulose, recycled cellulose, or a combination thereof.

[0034] According to some inventive embodiments, the MMCF is at least partially formed from sustainable wood pulp. According to some inventive embodiments, the MMCF is at least partially formed from cellulose pulp prepared from textile waste, agricultural waste, microbial cellulose, or a combination thereof. According to other inventive embodiments, the MMCF is at least partially formed from food waste.

[0035] The unique methods and techniques disclosed herein for mechanically combining these fibers in a certain weight percentage range produce a thread that provides a unique combination of the enhanced properties described above, including the ability to be fully recycled and biodegradable, while still providing a high strength comparable to that of synthetic materials that are not fully recyclable. According to some inventive embodiments, the core and sheath of the thread are present in a ratio of 60 - 90:40 - 10 (weight / weight). In some inventive embodiments, the core has a linear density of 85 to 280 dtex. According to an embodiment, the thread of the present invention has a total denier of 125 to 485 dtex.

[0036] In some inventive embodiments, the core fibers are continuous fibers. In some inventive embodiments, the sheath fibers are continuous or have a length of less than 65 mm and in some embodiments a length of 35 - 55 mm. Thus, the comfort of the textiles made therefrom is improved. According to some inventive embodiments, the single-layer core fibers are each spun with a Z-twist. Additionally, the single-layer sheath fibers are each spun with a Z-twist. The final two-layer thread is spun with an S-twist.

[0037] Due to the unique structure of the thread, the thread has improved higher strength and higher toughness compared to conventionally spun recyclable threads. According to some inventive embodiments, the filament strength of the thread is at least 600 cN. According to additional inventive embodiments, the filament strength of the thread is at least 1100 cN.

[0038] According to specific embodiments of the present invention, fibers with the most desired properties are selected. These fibers are then mechanically combined to form the threads of the present invention. These threads of the present invention produce enhanced desired properties that exceed the desired properties of the individual fibers. Weaving and knitting patterns can also produce a further enhancement of the desired properties.

[0039] The strength and characteristics of the final textile material depend substantially on the nature of the fibers, then on how the fibers are arranged into threads, and on the structure of the fabric. Based on the fiber lengths used in the core and sheath and the nature of the twisting process, the threads of the present invention are capable of imparting properties previously not available to the textiles or garments formed therefrom.

[0040] Understanding the basic properties of multiple fibers and the threads formed therefrom, and then uniquely mechanically arranging the fibers, provides threads with the desired properties of the multiple fibers, which in turn allows woven and knitted fabrics to utilize those desired properties. The additional mechanical properties of the weaving and knitting processes (i.e., the different patterns of weaving and knitting) can further enhance the desired properties.

[0041] As Figures 1A - 1CAs shown, an embodiment of the fully recyclable thread 10 of the present invention includes a core 12 and a thread covering 14 surrounding the core 12. The core 12 is formed of continuous short fibers, which are fibers geometrically characterized by a very high aspect ratio. Depending on the fiber, the fiber diameter is generally in the range of 3 - 200 μm. According to an embodiment, the MMCF short fibers are twisted and used as the core 12 of the thread 10 of the present invention. The core 12 twisted in the same direction as the covering 14 under controlled conditions achieves properties that were not previously available, and these properties are different from either of the individual MMCFs when these materials form the core and the covering respectively.

[0042] According to an embodiment, depending on the type of material used, the linear density of the staple short fibers forming the core 12 is at least 85 dtex and up to 280 dtex or more. According to some inventive embodiments, the core 12 is an untwisted yarn or a twisted yarn construction. According to an embodiment, the core is characterized by a Z-twist. According to an embodiment, the core has a special surface treatment provided thereon, which adds functions to the core. These functions improve the product performance and / or processability in applications. Examples thereof include the application of a water repellent finish or a bonding activation finish.

[0043] According to an embodiment, the MMCF short fibers are twisted into a yarn, which is used as the covering 14 of the thread 10. According to an embodiment, the MMCF of the covering is a staple yarn. According to an embodiment, the MMCF covering short fibers are characterized by a Z-twist.

[0044] According to an embodiment, the core 12 is thickly covered with covering fibers to form the covering 14 thereon. The covering 14 thickly covers the core 12, thereby enhancing the strength of the thread 10 of the present invention. Considering that the core 12 and the covering 14 are formed of similar materials, that is, both are formed of MMCF, the thread 10 of the present invention and the textiles formed therefrom can be easily recycled without the need for pre-sorting of different materials.

[0045] According to an embodiment, the thread 10 of the present invention has a linear density of Nm50 / 2 to Nm20; and a twist per meter (TPM) of 500 to 1200. According to an embodiment, the twisting is in the same direction, and according to an embodiment, this direction is in the S direction, while according to other embodiments, this direction is in the Z direction. It should be understood that over-twisting is generally required, especially in the thread 10 twisted in the S direction, to compensate for the twist relaxation in response to the internal tension generated by the twisting process.

[0046] According to an embodiment, the fully recyclable thread 10 of the present invention exhibits high toughness. Toughness is defined herein as the ratio of tensile strength to yarn fineness. Toughness is calculated using the ultimate breaking force of the yarn (when the thread or yarn is stretched to its breaking point) and the linear density, and can be used to compare different materials or different finenesses of materials. According to some inventive embodiments, the toughness of the thread of the present invention is 2.5 to 5.0 cN / tex. According to still other inventive embodiments, the breaking strength of the thread of the present invention is 700 to 1300 cN. According to an embodiment, the elongation of the thread of the present invention is 5% to 15%.

[0047] According to some inventive embodiments, the thread 10 may include a covering that covers the skin 14 of the thread 10. According to an embodiment, the covering is formed from recycled cotton, organic cotton, or a combination thereof.

[0048] According to an inventive embodiment, the thread 10 can be dyed in various colors. According to an embodiment, the thread 10 of the present invention is dyed using natural dyes. According to an embodiment, the thread 10 of the present invention is dyed using natural indigo dye. According to an embodiment, the thread of the present invention is dyed using a beam-to-beam dye. According to an embodiment, the thread is dyed during the polymerization or formation of the thread, thereby saving the time and processing steps of a separate dyeing operation, associated pollution, and cost. According to an embodiment, the thread of the present invention is treated with a surface treatment of chemicals or plasma to increase the affinity of the dye applied thereto.

[0049] Some inventive properties are detailed in Table 1 below.

[0050] Table 1. Toughness and Strength of Core and Covering at Various Ratios

[0051]

[0052] The present invention is further detailed with reference to the following examples. These examples are not intended to limit the scope of the appended claims.

[0053] Example 1

[0054] The thread of the present invention is prepared from Lyocell. The thread has a core and a skin applied thereto. The spun Lyocell thread has a tkt. of 120 and 24 tex (tex). The resulting thread was then tested to determine the nominal grist, sizing, strength, toughness, % elongation, and TPI. The nominal grist was obtained as 240 to 310, the sizing was 100 to 150 dtex, the strength was 690 to 1,300 cN, the toughness was 20 to 50 cN / tex or 2 to 6 g / den, the % elongation was 6% to 20%, and the TPI was 18 to 30.

[0055] The patent documents and publications mentioned in the specification indicate the level of those skilled in the art to which the present invention pertains. These documents and publications are incorporated herein by reference to the extent that each individual document or publication is specifically and individually incorporated herein by reference.

[0056] The foregoing description illustrates specific embodiments of the present invention, but is not meant to be limiting of its practice. The appended claims (including all equivalents thereof) are intended to define the scope of the present invention.

Claims

1. A fully recyclable thread, the fully recyclable thread comprising: a core (12); and a thread covering surrounding the core (14); wherein both the core and the thread covering are formed of man-made cellulose fiber (MMCF).

2. The fully recyclable thread according to claim 1, wherein the core and the thread covering are joined by a unique core-spun spinning technique using ring spinning, modified ring spinning, short spinning, two-fold spinning, vortex spinning, and air-jet spinning techniques.

3. The fully recyclable thread according to any one of claims 1 to 2, wherein the thread is dyeable.

4. The fully recyclable thread according to any one of claims 1 to 3, wherein the filament strength of the thread is in the range of 600 cN to 2400 cN based on the construction and thickness of the material.

5. The fully recyclable thread according to any one of claims 1 to 4, wherein the core and the thread covering are present in a ratio between 60%-90% and 40%-10%.

6. The fully recyclable thread according to any one of claims 1 to 5, wherein both the core and the thread covering are twisted in the Z direction.

7. The fully recyclable thread according to any one of claims 1 to 6, wherein both the core and the thread covering are twisted in the S direction.

8. The fully recyclable thread according to any one of claims 1 to 7, wherein the tenacity of the thread is 3 to 8.5 grams / denier.

9. The fully recyclable thread according to any one of claims 1 to 8, wherein the MMCF is Lyocell.

10. The fully recyclable thread according to claim 9, wherein the Lyocell comprises native cellulose.

11. The fully recyclable thread according to claim 9, wherein the Lyocell comprises recycled cellulose.

12. The fully recyclable thread according to any one of claims 1 to 8, wherein the MMCF is at least partially formed of sustainable wood pulp.

13. The fully recyclable thread according to any one of claims 1 to 8, wherein the MMCF is at least partially formed of cellulose pulp prepared from textile waste, agricultural waste, microbial cellulose, or a combination thereof.

14. The fully recyclable thread according to any one of claims 1 to 8, wherein the MMCF is at least partially formed of food waste.

15. The fully recyclable thread according to any one of claims 1 to 14, the fully recyclable thread further comprising a covering covering the thread covering.

16. The fully recyclable thread according to claim 15, wherein the covering is formed of recycled cotton, organic cotton, or a combination thereof.

17. The fully recyclable thread according to any one of claims 1 to 16, wherein the fully recyclable thread has a twist per meter (TPM) of 500 to 1200.

18. A method of forming the fully recyclable thread according to claim 1, the method comprising: providing a core; providing a thread covering; layering the thread covering around the core; and twisting the layered thread covering and core together.

19. The method according to claim 18, further comprising applying a surface treatment to the fully recyclable thread.

20. The method according to any one of claims 18 or 19, further comprising dyeing the fully recyclable thread using natural dyes.

21. The method according to any one of claims 18 to 20, further comprising applying a bio-based lubricant to the fully recyclable thread.

22. The method according to any one of claims 18 to 21, wherein at least one of the core thread or the sheath thread is derived from at least one of the following sustainable sources: wood pulp, textile waste, agricultural waste, food waste, chemically modified wood pulp using ionic liquids, or any other waste stream composed of cellulose-rich components.

23. The method according to claim 22, wherein both the core thread and the sheath thread are derived from the sustainable source.

24. The method according to claim 23, wherein the core thread and the sheath thread are derived from a single sustainable source.

25. The method according to claim 23, wherein the core thread and the sheath thread are each derived from different types of the sustainable source.

26. Use of the thread according to any one of claims 1 to 18 for forming a fabric or a garment formed from the fabric.

27. The use according to claim 26, wherein the garment is formed without using synthetic sewing thread.

28. The use according to claim 27, further comprising recycling the garment.

29. The fully recyclable thread according to any one of claims 1 to 17, wherein the thread is finished with antistatic, antimicrobial, and flame-retardant finishing agents.

30. The fully recyclable thread according to any one of claims 1 to 17, wherein the thread is coated with a chemical for improving abrasion resistance.

31. The fully recyclable thread according to any one of claims 1 to 17, wherein the thread is coated with a bio-enzyme to improve hairiness.

32. The fully recyclable thread according to any one of claims 1 to 17, wherein the thread comprises a blend of refractory fibers.

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