Yarn comprising a filament core and a staple fiber sheath, textile article, natural cellulosic staple fiber blend and method for producing a yarn

Description

1 / 25 “YARN COMPRISING A FILAMENT CORE AND A SHEATH OF DISCONTINUOUS FIBER, TEXTILE ARTICLE, MIXTURE OF NATURAL CELLULOSIC DISCONTINUOUS FIBERS AND METHOD FOR PRODUCING A YARN Field of invention

[0001] The present invention relates to the field of yarn production. In more detail, the present invention relates to a yarn that uses short cellulosic fibers, for example, cotton, staple fibers normally obtained from the recycling of yarns and fabrics, and to a process for producing said yarn. The invention also relates to a method for recycling cotton fabrics. State of the art

[0002] Due to the costs and environmental impact of natural fiber production, methods have been developed to recycle natural fibers from textile waste in order to reuse them. A prominent example is the recycling of cotton from textile waste, particularly fabric and yarn waste, in order to obtain recycled cotton fibers.

[0003] Known recycling processes for textiles and yarns generally involve the mechanical breakdown of textiles into loose fibers that can be used to spin new yarns. In this process, machines are used that break down the fabric, for example, by means of rotating drums with metal pins. The mechanical tension on the yarn fibers causes the original fibers to break into shorter fibers.

[0004] One problem with recycled cotton fibers is that their content of short-length fibers makes them Petition 870250094653, dated 10 / 16 / 2025, page 15 / 48 2 / 25 unsuitable or inappropriate for yarn manufacturing, particularly in ring spinning machines for denim production. Virgin cotton staple fibers have a higher quantity of long fibers than recycled cotton fibers; for example, the average length L(n) (considering all the fibers in a yarn) of virgin cotton is generally greater than 20 mm, while recycled cotton staple fibers have an average length L(n) that is generally less than 15 mm, usually between 6 and 15 mm, most commonly between 9-12 mm.

[0005] Therefore, it is difficult to properly use recycled (short) cotton fibers in the production of yarn by ring spinning.

[0006] The short length of cotton fibers results in a yarn with very low strength, resulting in poor fabric, or it may not even be workable into a yarn due to the combined fiber breaks that occur in yarn-making machines. For this reason, recycled cotton fibers have been blended with virgin cotton fibers to give the final yarn acceptable mechanical properties and physical characteristics, such as bulk and appearance, of yarns containing 100% virgin natural fiber, for example, virgin cotton. The ratio between the amount of virgin cotton (CO) fibers and recycled cotton (RCO) fibers by weight in a yarn depends on the yarn production technique. Typically, open-end yarns can be composed of up to 100% recycled cotton, while in ring-spun yarns the RCO content does not exceed 40% (by weight) and generally the CO / RCO ratio (by weight) is in the range of 70 / 30 to 90 / 10. Petition 870250094653, dated 10 / 16 / 2025, page 16 / 48 3 / 25

[0007] It has also been proposed to improve the mechanical properties of yarns containing recycled cotton fibers by using polyester filaments and fibers. In one embodiment, polyester staple fibers are blended with cotton fibers before being spun into a yarn; these yarns have the disadvantage that, due to the presence of polyester, they cannot be easily dyed and have a poor appearance, i.e., an appearance that is not cotton-like. The proposed embodiments in which polyester filaments are provided as core filaments in a recycled cotton sheath have the aforementioned disadvantage of necessarily having a low recycled cotton fiber content. Furthermore, they also failed to solve the problem, mainly because the recycled cotton fiber sheath breaks easily when stretched or tensioned.

[0008] There is therefore a need to solve the problems of the state of the art and provide a yarn in which all the cotton fibers are recycled fibers, the yarn is a ring-spun yarn and has a good appearance and good to excellent mechanical characteristics. Summary of the invention

[0009] An objective of the present invention is therefore to provide a yarn in which all cotton fibers can be recycled, of short length, cotton fibers and having good to excellent mechanical properties and the appearance and aspect of a yarn including virgin cotton fibers.

[0010] Another objective of the invention is to provide a spun yarn with a core containing cotton fibers of length Petition 870250094653, dated 10 / 16 / 2025, page 17 / 48 4 / 25 short, elastic and stretchy.

[0011] The aforementioned objectives are achieved by means of the present invention which relates to a wire according to claim 1.

[0012] The invention also relates to a method of producing a spun yarn with a core containing recycled cotton fibers, i.e., of short length, according to claims 13 and 16. Another object of the invention is a mixture of staple fibers according to claim 12.

[0013] In particular, the present invention relates to a yarn and a relevant production method according to the appended independent claims, while the preferred aspects are cited in the dependent claims.

[0014] The expression “fiber blend” in the present description is used to identify a mixture of different fibers that is suitable for use in a ring spinning process to provide the sheath of a spun core yarn. Single fibers in the sheath of the yarn of the invention can be identified and, if necessary, physically removed from the mixture that forms the sheath.

[0015] For the present invention, the term “regenerated cellulosic fiber” or “synthetic fiber” indicates any type of discontinuous cellulose-based fiber that is industrially produced. This term includes all types of regenerated cellulosic fibers, such as lyocell, viscose, modal, bamboo (commercially available bamboo fiber is generally a regenerated cellulosic fiber produced from bamboo, i.e., a synthetic rayon made from cellulose extracted from bamboo), polynosic fiber, cupro, acetate, etc. These fibers Petition 870250094653, dated 10 / 16 / 2025, page 18 / 48 5 / 25 discontinuous artificial fibers have a substantially constant length, so that the length of these fibers falls within a very small range, i.e., they have a low CV value (i.e., coefficient of variation). For the present invention, the average length of these fibers, measured according to DIN 53805:1980-06, is in the range of 25 mm to 38 mm, preferably from 29 mm to 35 mm. The preferred count of regenerated fibers suitable for the invention is in the range of 1 dtex to 3 dtex, preferably about 1.2 dtex. The preferred regenerated cellulosic fibers for the present invention are sustainable cellulosic fibers, such as FSC-certified regenerated cellulosic fibers.

[0016] For the present invention, the term “virgin fiber” indicates cotton staple fibers derived from cotton that has not been worked into yarns and fabrics and that therefore has a high average fiber length.

[0017] For the present invention, the term “natural cellulosic fibers” means fibers obtained from the body of plants or animals. Preferred natural cellulosic fibers are fibers obtained or obtainable from the recycling process of fabrics and fibers from plants such as cotton, hemp, flax, and so forth. Typically, the natural cellulosic fibers used in the invention are recycled fibers, with counts close to each other, and are generally within the count range of regenerated cellulosic fibers.

[0018] The term “recycled cotton fibers” in the following description indicates cotton staple fibers derived from mechanical treatments, for example, opening and Petition 870250094653, dated 10 / 16 / 2025, page 19 / 48 6 / 25 sorting, of yarns and fabrics; one possible way to identify these fibers is by measuring their average fiber length. In embodiments, the average fiber length L(n), measured with DIN 53805:1980-06, is in the range of 6 to 16 mm. Tow falls within the definition of recycled cotton fibers. As is known, tow is a short fiber produced as waste in yarn production, typically removed from the yarn during the combing process.

[0019] Table 1 below summarizes the fiber dimensions of a fiber blend used as a sheath in a yarn according to the invention. These results can be obtained by known methods (e.g., DIN 53805:1980-06 or ASTM D1447) and known machines (e.g., Uster Afis Pro 2 or Textechno FCS-Fibrotest). Table 1 Fiber Sheath Preferred Value(s) Min Max Average Length L(n) 12 - 20 10 25 L(n) CV % 60 - 70 50 80 Short Fiber Content (less than 12 mm) SFC (n) O >40 30 70

[0020] Note that the values ​​above are obtained according to the DIN 53805:1980-06 standard, i.e., as an average value. The minimum (Min) and maximum (Max) in the table above are the minimum and maximum values ​​of this average. As Petition 870250094653, dated 10 / 16 / 2025, page 20 / 48 7 / 25 result, with reference, for example, to the average length, the embodiments of the invention have an average length between 10 and 25 mm, preferably between 12 and 20 mm.

[0021] Tables 2 and 3 below summarize the corresponding values ​​for the artificial or regenerated staple fibers used in the present invention. Table 2 Natural cellulosic fibers Preferred value(s) Min Max Average length L(n) 6 - 16 5 20 L(n) CV % 60 - 80 40 90 Short fiber content (less than 12 mm) SFC )u) % 50 - 70 40 80 Table 3 Regenerated cellulosic fibers Preferred value(s) Min Max Average length L(n) 30 - 34 28 36 L )u) CV % 20 - 30 0 50 Short fiber content (less than 12 mm) SFC )u) % 1 - 5 0 10

[0022] For example, recycled cotton fibers (short-length fibers) may have the specifications defined below in terms of average fiber length in numerical terms Ln. Average fiber length in numerical terms (Ln): 10.0 mm Petition 870250094653, dated 10 / 16 / 2025, page 21 / 48 8 / 25 CV %: 70.0 Short fiber content - less than 12.0 mm %: 60.0

[0023] The same histogram applied to discontinuous viscose fibers typically yields the following values: Average fiber length (in numerical terms) (Ln): 32.0 mm CV %: 24 Short fiber content (length less than 12 mm) SFC(n) %: 2.8 The above results are obtained with an Uster Afis Pro 2.

[0024] Average fiber length in numerical terms Ln can be calculated using the following formula: _lnili^n V Σ^ί where: Ln is the average fiber length in numerical terms, ni is the number of fibers with length li, and li is the length of fiber i.

[0025] Furthermore, as is known in the field, the Coefficient of Variation (CV%) is the ratio between the standard deviation s of a distribution of measurements and its mean value x, namely: CV% = =*100 x

[0026] In the final blend of the sheath, the high 5% (n) index is mainly due to the presence of longer regenerated cellulosic fibers, while the high SFC(n) value is mainly due to the presence of the first short fibers, for example, recycled cotton fibers with a high percentage of short fibers.

[0027] According to the invention, the yarn is a spun yarn Petition 870250094653, dated 10 / 16 / 2025, page 22 / 48 9 / 25 with a core comprising or consisting of polyester filaments. The linear density of the polyester filaments is in the range of 20 to 300 denier. The number of filaments is in the range of 6 to 288, while the total count for the final yarn is in the range of 5 / 1 to 60 / 1 Ne. In preferred embodiments, the ratio of the weight of the polyester filaments to the total weight of the yarn is in the range of 10 to 30%.

[0028] In embodiments, the elongation at break of the polyester filaments of the yarn core is less than 15%, more preferably between 8% and 12%, even more preferably between 10% and 12%, when tested with DIN ISO 2062.

[0029] According to one aspect of the invention, a yarn comprises a filament core and a staple fiber sheath. The fiber sheath is made of first and second fibers. The first fibers are natural cellulosic fibers, preferably recycled cotton staple fibers with an average length in the range of 6 to 16 mm, even more preferably about 10 mm.

[0030] Secondary fibers are artificial fibers, i.e., regenerated staple fibers, preferably viscose, with an average length greater than the average length of the primary fibers, preferably between 25 mm and 40 mm, more preferably between 28 mm and 36 mm. High-quality yarns have been achieved, in particular, with secondary fibers around 32 mm, as well as between 30 and 34 mm.

[0031] At least 95% of the fibers in the sheath are the first and second fibers mentioned above, where the weight ratio of the first fiber to the second fibers is Petition 870250094653, dated 10 / 16 / 2025, page 23 / 48 10 / 25 between 70 / 30 and 80 / 20.

[0032] In other words, the preferred embodiments have a hem composed (by at least 95% of its weight) of a blend made of 70% to 80% first fibers, i.e., recycled cotton fibers, while the remaining 20% ​​to 30% by weight of the blend is made of second fibers, i.e., viscose.

[0033] In a preferred embodiment, recycled cotton fibers are about 75% by weight of the blend and regenerated cellulosic fibers, for example, viscose, are 25% by weight of the blend.

[0034] The blending of the fiber sheath, as well as the presence of one or more polyester filaments in the core, allows the claimed fibers and filament to be worked into a yarn which, in turn, is workable into a fabric that has excellent market properties. In particular, the resulting yarn can be ring spun, i.e., a process that was previously not possible to perform on yarns with a high percentage of short fibers, such as recycled cotton fibers.

[0035] The average length of the sheath fibers (i.e., of all the fibers in the sheath) is between 10 and 25 mm, preferably between 12 and 20 mm. The average length is the value L(n) measured according to the DIN 53805:1980-06 standard.

[0036] Testing machines that can measure the above-mentioned indices, namely L(n), 5%(n), SFC(n), such as USTER AFIS PRO 2 or Textechno FCS-Fibrotest, are known in the art.

[0037] In the sheath, the 5%(n) fiber content (as previously measured according to DIN 53805:1980-06) is 5% Petition 870250094653, dated 10 / 16 / 2025, page 24 / 48 11 / 25 minus 25 mm, preferably between 25 mm and 40 mm, more preferably between 28 and 38 mm, and wherein the short fiber content SFC(n) (measured according to DIN 53805:1980-06) of the sheath is between 30% and 70%, with values ​​above 35% being preferred, more preferably above 40%, i.e., between 40 and 70%.

[0038] According to a preferred aspect, the elongation at break of the polyester filaments of the filament core is less than 15%, preferably between 5% and 15%, more preferably between 8% and 12%, even more preferably between 10% and 12%, when tested with DIN ISO 2062.

[0039] The claimed elongation at break is the elongation of all the core filaments, tested together.

[0040] It has been found, in particular, that if the core elongation is low (i.e., less than 15%, as mentioned above), yarn production and weaving processes are facilitated. In particular, in these embodiments, the core elongation is generally similar to the elongation of cotton fibers.

[0041] In fact, if the final yarn is tensioned, a high-stretch polyester core (i.e., more than 15% or more than 20%) can cause core sheath slippage and / or can cause a break in the discontinuous fiber sheath.

[0042] The use of low-stretch polyester filament(s) in the core helps to avoid the aforementioned problems.

[0043] Low-stretch polyester filaments are known in the art and are available Petition 870250094653, dated 10 / 16 / 2025, page 25 / 48 12 / 25 commercially. They can be obtained in different ways. One possible solution could be to provide a sketch during a texturing step of POY polyester filaments. This sketch is preferably between 1.7 and 2.5, more preferably between 1.8 and 2.1.

[0044] Polyester filaments are in fact preferably textured and, as mentioned, the outline can be applied during the texturing process, usually also heating the filaments during the outline stage in the texturing process.

[0045] According to one aspect, the amount of polyester filaments in the core is between 10% and 35% of the yarn weight, more preferably between 15% and 25%, even more preferably around 20%. The percentage above refers to the total count of polyester filaments, i.e., the total sum of the filament count.

[0046] According to one aspect, the total count of polyester filaments is between 50 and 150 den, more preferably between 60 and 120 den, even more preferably between 75 and 100 den.

[0047] As mentioned, the second fibers of the sheath have a greater average length than the average length of the first fibers.

[0048] Fiber length can be measured using suitable machines, such as the Uster Afis Pro 2 or TexTechno FCS-Fibro test, with methods known in the art, such as AFIS (Advanced Fiber Information System) according to DIN 53805:1980-06 or ASTM D1447.

[0049] To measure the nature of the fiber and the fiber length (i.e., the L(n), SFC(n) and 5%(n) values) of the sheath Petition 870250094653, dated 10 / 16 / 2025, page 26 / 48 13 / 25 of a finished yarn, the sheath must initially be separated from the core. This can be done by unwinding the yarn (i.e., applying a twist opposite to that of the yarn, such as S-twisting a Z-twisted yarn). This can be done manually or by a twisting machine.

[0050] The fibers obtained can then be tested to determine their nature, that is, to determine the presence of natural cellulosic fibers and regenerated cellulosic fibers. Possible known methods are AATCC 20 and 20A, or ISO 1833.

[0051] Subsequently, the fiber length can be tested, for example, via DIN 53805 or ASTM D1447, using a USTER AFIS PRO 2 or a Textechno FCS-Fibrotest.

[0052] Preferably, to provide better interaction between the first and second fibers of the sheath, the length of the second fibers is not much greater than the length of the first fibers. A preferred ratio between the average length L(n) of the second fibers versus the average length L(n) of the first fibers is between 1.5 and 3.8, more preferably between 2 and 3.5. The best results occurred when the ratio discussed above is between 2.5 and 3.3.

[0053] The yarn, according to one or more of the preceding aspects, can be used to produce a fabric, in particular a woven fabric (preferably denim) and a garment that includes that fabric. It is particularly possible to produce a fabric in which the yarns according to the invention are used in both the warp and weft directions.

[0054] It has been found that a fabric of this type, and especially a garment made from this fabric, can be Petition 870250094653, dated 10 / 16 / 2025, page 27 / 48 14 / 25 manufactured without virgin (i.e., conventional) cotton, although it has similar wearability (hand, softness, etc.) and optical properties (brightness, dyeing, etc.) to a fabric made from conventional cotton yarns. Furthermore, compared to fabrics made from conventional cotton yarns, the fabric according to the present invention exhibits similar mechanical properties, such as similar tensile strength, as well as better abrasion properties.

[0055] As an example, the abrasion of fabrics can be tested using the BS EN ISO 12947-2 method and the test, for which 25,000 to 30,000 cycles are performed.

[0056] If the test is continued even after this number of cycles, until the fabric breaks, a fabric according to the present invention has greater resistance (i.e., breaks after a greater number of cycles) compared to a standard cotton yarn fabric or a fabric made with recycled cotton yarns.

[0057] It has been tested that, if three identical pieces are tested, the only difference between the garments being a first piece made with virgin cotton yarns, the second piece with recycled cotton yarns, the third piece made according to the present invention, with recycled cotton fibers as first fibers, if the abrasion test is continued until the tested garment breaks, the third piece will last 2 to 3 times the duration of the first piece and 3 to 4 times the duration of the second garment.

[0058] The core may consist of a plurality of polyester filaments, or it may also include elastomeric filaments, such as elastane. Typically, in this case, the Petition 870250094653, dated 10 / 16 / 2025, page 28 / 48 15 / 25 core consists of polyester and elastomeric filaments.

[0059] The elastomeric filaments are generally in the range of 40 to 140 den, which are generally sketched at least 2.0 times, more preferably about 3 times before sheath application, so that their count on the yarn would be lower (with a 3.0 sketch it would be between about 13 and 47 den). In particular, the elastomeric filaments preferably have a sketch of 2.0 to 4.0, more preferably at least 2.5, preferably about 3.0.

[0060] One aspect of the present invention also relates to a blend of natural cellulosic staple fibers, preferably cotton staple fibers, and regenerated cellulose staple fibers, preferably viscose staple fibers, for a yarn according to any of the foregoing aspects, wherein: the weight ratio of said natural cellulosic fibers to said regenerated cellulose fibers is in the range of 70 / 30 to 80 / 20, preferably said ratio being about 75 / 25; the average length of the fibers in the blend is in the range of 10 to 25 mm, preferably from 12 mm to 20 mm; the 5% index (n) of the fibers in said blend is at least 25 mm, preferably at least 28 mm, more preferably in the range between 28 and 38 mm; the short fiber content SFC(n) of the sheath is at least 30%, preferably at least 40%.

[0061] The present invention also relates to a method of producing a yarn comprising the steps of: a) Selecting a filament core comprising a plurality of polyester filaments; b) Selecting the Petition 870250094653, dated 10 / 16 / 2025, page 29 / 48 16 / 25 first fibers which are natural cellulosic fibers; c) Select the second fibers which are regenerated cellulosic fibers; d) Provide a staple fiber sheath comprising at least 95% by weight of a mixture of said first fibers and said second fibers, wherein the weight ratio of said first fibers to said second fibers is in the range of 70 / 30 to 80 / 20, preferably said ratio being about 75 / 25, wherein the fibers of the sheath have an average length between 10 and 25 mm, preferably between 12 and 20 mm, wherein the 5%(n) index of the fibers of the sheath is between 25 mm and 40 mm, preferably between 28 and 38 mm, and wherein the short fiber content SFC(n) of the sheath is between 30% and 70%, more preferably between 40% and 70%; to combine said filament core and said discontinuous fiber sheath, by means of ring spinning;

[0062] The present invention also relates to a method of producing a yarn comprising the steps of: a) Selecting a filament core comprising a plurality of polyester filaments; b) Selecting a discontinuous fiber sheath in which at least 95% of the sheath is made of first fibers and second fibers, the first fibers being natural fibers, preferably with an average length between 6 and 16 mm, the second fibers being regenerated cellulosic fibers, preferably with an average length greater than the first fiber and preferably greater than 25 mm, more preferably greater than 30 mm, said first fibers being recycled cotton fibers, said second fibers being regenerated cellulosic fibers, the weight ratio of Petition 870250094653, dated 10 / 16 / 2025, pp. 30 / 48 17 / 25 of the aforementioned first fibers to the aforementioned second fibers is in the range of 70 / 30 to 80 / 20, preferably the aforementioned ratio being about 75 / 25; c) combine the aforementioned filament core and the aforementioned discontinuous fiber sheath, preferably by ring spinning.

[0063] As mentioned, recycled materials are preferably used, so that the first fibers of the hem are recycled cotton fibers and / or the polyester filaments are made of recycled polyester. Detailed description of the invention

[0064] Exemplary and non-limiting achievements will now be discussed with reference to the attached non-limiting figures, where: - Fig. 1 is a histogram of recycled cotton fibers, - Fig. 2 is a histogram of a mixture of fibers from a yarn sheath according to the invention; Figures 3a and 3b are a comparison of a test performed on fibers of the same yarns made according to the invention, removed from a fabric (Fig. 3a) and before being woven (Fig. 3b).

[0065] To facilitate the discussion, in the general discussion that follows, reference will be made to:

[0066] - Recycled cotton fibers as the first hem fibers. However, unless otherwise specified, the following description applies to other natural cellulosic fibers as first hem fibers;

[0067] - viscose fibers as the second hem fibers. However, unless specified, the following description applies to other regenerated cellulosic fibers as second hem fibers; Petition 870250094653, dated 10 / 16 / 2025, page 31 / 48 18 / 25

[0068] - Elastane filaments possibly present in the core as one or more elastomeric filaments. However, unless specified, the following description applies to cores comprising a single elastane filament as well as one or more different elastomeric filaments.

[0069] In preferred embodiments, a yarn comprises a core provided with polyester filaments and possibly also elastane filaments; the sheath is made of staple fibers comprising recycled cotton fibers and viscose fibers.

[0070] Polyester filaments typically make up between 10% and 35% of the total yarn weight, usually around 20% of the yarn. The total polyester filament count is typically between 20 and 300 den, while more preferred embodiments use a total polyester count between 75 and 100 den.

[0071] The elongation at break of polyester filaments (i.e., of the polyester core component) is less than 15%, more preferably between 8% and 12%, even more preferably between 10% and 12%. The test for measuring elongation at break is DIN ISO 2062.

[0072] By comparison, a traditional polyester yarn, initially produced with the same method but without the claimed outline, will be heavier (i.e., as having a higher count) and a greater elongation at break when tested with the same test, above 15%, generally in the range of about 17% - 25%.

[0073] If present, elastane is usually highly outlined (with an outline greater than 2.0, generally around Petition 870250094653, dated 10 / 16 / 2025, pp. 32 / 48 19 / 25 3.0) and is present in low weight amounts in the yarn, and therefore generally around 5 to 15% of the total yarn weight.

[0074] According to one aspect, the polyester filaments and the elastane filaments are combined at least at a plurality of connection points, in a known manner, and preferably by means of mixing, twisting or mechanical co-extrusion. As mentioned, the elastane filaments are preferably drawn before being combined with the polyester filaments.

[0075] According to one aspect, the continuous core fibers and the elastomeric filament(s) are connected continuously or substantially continuously by “mechanical co-extrusion of the filaments, preferably in a tensioned condition. During this co-extrusion, also known as co-feeding, two (or more) fiber bundles (in a tensioned state) are forced (fed together) through a restriction in which the fibers join together to such an extent that they remain locked even after exiting the restriction.

[0076] The hem is composed of staple fibers. At least 95% of the staple fibers in the hem are a blend of recycled cotton fibers, with 70% to 80% by weight of the blend being made of recycled cotton fibers, while the blend is viscose fibers.

[0077] Preferred realizations have approximately 75% recycled cotton fibers and 25% viscose fibers. The remaining portion (up to 5%), if present, may be other staple fibers. Typically, even if the blend of recycled cotton and viscose fibers is not 100% of the hem fibers, the recycled cotton fibers are at least 100%. Petition 870250094653, dated 10 / 16 / 2025, pp. 33 / 48 20 / 25 minus 60%, generally at least 65%, of the hem weight. When the blend of recycled cotton and viscose fibers is substantially 100% of the hem fibers, the recycled cotton fibers are between 70% and 80% of the hem weight.

[0078] The average length of recycled cotton fibers is between 6 and 16 mm.

[0079] Typically, more than 90% (by number) of recycled cotton fibers are below 30 mm. Achievements are possible where 50% of the fibers are below 15 mm.

[0080] Viscose fibers are longer than recycled cotton fibers in order to provide hem strength. However, as mentioned, it is preferable that they are not much longer than recycled cotton fibers in order to promote the coupling and blending of the hem fibers.

[0081] Viscose fibers have an average length greater than 25 mm, preferably greater than 30 mm, generally between 28 mm and 36 mm. In particular, it has been observed that very long viscose fibers can decrease the quality of the final yarn. In view of this, the most preferred embodiments use viscose fibers around 32 mm, such as between 30 mm and 34 mm. Typically, regenerated cellulosic staple fibers, such as viscose staple fibers, have uniform length, being produced by cutting viscose filaments.

[0082] Viscose filaments are preferably chosen so that their average length is between 1.5 and 3.8 times the average length of recycled cotton fibers, preferably between 2 and 3.5 times, even more preferably between 2.5 and 3.3 times the average length. Petition 870250094653, dated 10 / 16 / 2025, pp. 34 / 48 21 / 25 of the fibers are recycled cotton.

[0083] Viscose fibers and recycled cotton fibers are blended to form a mixture that is at least 95% by weight of hem fibers. As discussed, the ratio (by weight) between viscose fibers and recycled cotton fibers is between 20 / 80 and 70 / 30.

[0084] The average length of the sheath fibers is between 10 and 25 mm, preferably between 12 and 20 mm, while the 5%(n) index of the sheath fibers is at least 25 mm, preferably between 25 mm and 40 mm, more preferably between 28 and 38 mm. The short fiber content SFC(n) of the sheath is at least 35%, preferably at least 40%.

[0085] Apparatus for producing yarns is known in the art and is not discussed in detail here.

[0086] The yarn production method according to the present invention comprises providing a core, drawing polyester filaments and possibly combining them with elastane filaments.

[0087] The core is then combined with the sheath, which is usually provided in the form of one or more strands of discontinuous fiber.

[0088] The resulting product is then spun into yarn, preferably by ring spinning.

[0089] The yarn obtained can be used in a textile article and, in particular, a plurality of yarns according to the invention can be used in a fabric. In particular, they can be used as warp and / or weft yarns of the fabric.

[0090] It is in particular an object of the invention a fabric, preferably a denim fabric, in which all the yarns of Petition 870250094653, dated 10 / 16 / 2025, pp. 35 / 48 22 / 25 warp and weft are yarns according to the invention.

[0091] Warp yarns can be dyed, for example, dyed indigo, while weft yarns can be left undyed (although dyeing is possible).

[0092] As mentioned, a fabric obtained with the yarns according to the present invention is provided with better abrasion performance compared to fabrics made with standard cotton yarns and recycled cotton yarns.

[0093] An exemplary comparison is proposed below.

[0094] Fabric 1 is a fabric made with standard cotton yarns, while Fabric 2 is a fabric made with warp and weft yarns according to the invention.

[0095] Fabric 1 is made according to the following parameters: - Warp yarn composition: 100% cotton - Warp thread count: 10 / 1 Ne - Composition of the weft yarns: 94% cotton / 6% elastane - Weft thread count: 16 / 1 Ne - Woven fabric: 3 / 1 denim fabric, - Fabric composition: 98% cotton / 2% elastane.

[0096] Fabric 2 is made according to the following parameters: - Composition of warp yarns: 61% recycled cotton / 20% viscose / 19% recycled polyester - Warp yarn count: 10 / 1 Ne (same as Fabric 1) - Weft yarn composition: 60% recycled cotton / 20% viscose / 14% recycled polyester / 6% elastane - Weft thread count: 16 / 1 Ne (same as fabric 1) - Woven fabric: 3 / 1 denim fabric (same as fabric 1) - Fabric composition: 60% cotton / 20% viscose / 18% Petition 870250094653, dated 10 / 16 / 2025, pp. 36 / 48 23 / 25% recycled polyester / 2% elastane.

[0097] The two fabrics were tested as follows: Table 4 Tear strength in grams Raw After 5 home washes After 10 home washes Fabric 1 weft 3068 7577 2832 7070 2650 7030 warp Fabric 2 weft 2982 8450 3400 8304 2832 7679 warp The tear test is performed according to ISO 13937-1, 5 and 10 domestic washes are carried out at 40°C, normal procedure, followed by machine drying. In each cell, the top line shows the value in the weft direction, the bottom line shows the value in the warp direction. Table 5 Tensile strength in kg (raw) After 5 home washes After 10 home washes Fabric 1 weft 57.4 171.4 48.48 171.1 54.07 173.04 warp Fabric 2 weft 58.8 167.5 47.97 172.38 53.24 174.48 warp The tensile strength test is performed in accordance with ISO 1393-1, 5 and 10 domestic washes are carried out at 40°C, normal procedure, followed by machine drying. In each cell, the top line shows the value in the direction of Petition 870250094653, dated 10 / 16 / 2025, pp. 37 / 48 24 / 25 weave, the bottom line shows the value in the warp direction. Table 6 Abrasion resistance: Number of cycles required to break the fabric. Fabric 1: 93,000. Fabric 2: 186,000. The abrasion test is performed in accordance with ISO 12947-2 and continues until the tested fabric breaks.

[0098] As can be seen from the tests above, a fabric according to the invention has similar tensile strength and slightly improved tear resistance compared to a standard virgin cotton fabric. As a result, a fabric according to the invention has similar usability, while maintaining similar optical properties, compared to a standard virgin cotton fabric.

[0099] In addition, the fabric of the invention exhibits improved abrasion resistance, thus improving the fabric's lifespan.

[0100] The composition and length of the fiber can be tested according to the methods discussed above. They can be tested before being woven and after being woven, by removing them from a fabric, with similar results. In this sense, Figures 1 and 2 are tested on fibers that are not being woven into a fabric. Figures 3a and 3b show the comparison between fibers from the same yarn set according to the invention, where the test fibers Petition 870250094653, dated 10 / 16 / 2025, pages 38 / 48 25 / 25 of Fig. 3a come from a yarn removed from a fabric, while the fibers in the test of Fig. 3b come from a yarn after yarn production, before being woven into a fabric. As can be seen, the fiber length distribution is substantially the same. Petition 870250094653, dated 10 / 16 / 2025, pp. 39 / 48

Claims

1 / 5 CLAIMS 1) Yarn comprising a filament core and a staple fiber sheath, said staple fiber sheath comprising at least 95% by weight or consisting of a mixture of first fibers and second fibers, wherein the first fibers are natural cellulosic fibers and the second fibers are regenerated cellulosic fibers, characterized in that: the weight ratio of said first fibers to said second fibers is in the range of 70 / 30 to 80 / 20, preferably said ratio being about 75 / 25; the average length of the sheath fibers is in the range of 10 to 25 mm, preferably 12 mm to 20 mm; the 5%(n) index of the sheath fibers is between 25 mm and 40 mm, more preferably in the range between 28 and 36 mm, even more preferably between 30 and 34 mm; The short fiber content SFC(n) of the sheath is between 30% and 70%, preferably between 40% and 60%;and the said filament core comprises a plurality of polyester filaments. 2) Yarn, according to claim 1, characterized in that the elongation at break of the polyester filaments of the filament core, measured in accordance with DIN ISO 2062, is in the range of 5% to 15%, more preferably between 10% and 12%. 3) Yarn, according to either claim 1 or 2, characterized in that the natural cellulosic fibers are recycled cotton fibers. 4) Yarn, according to any of claims 1 to Petition 870250094653, dated 10 / 16 / 2025, page 40 / 48 2 / 5 3, characterized in that the ratio between the average length of the regenerated cellulosic fibers to the average length of the first fibers is in a range between 1.5 and 3.8, preferably between 2 and 3.5, more preferably between 2.5 and 3.

3. 5) Yarn, according to any one of claims 1 to 4, characterized in that the core comprises one or more elastomeric filaments, preferably with a diameter of 2.0 to 4.0, more preferably of at least 2.5, preferably of about 3.

0. 6) Yarn, according to any one of claims 1 to 5, characterized in that the polyester filaments have a draft between 1.5 and 2.5, preferably between 1.8 and 2.

2. 7) Yarn, according to any one of claims 1 to 6, characterized in that the polyester filaments are textured filaments. 8) Yarn, according to any one of claims 1 to 7, characterized in that the amount of polyester filaments in the core is in the range of 10% to 30% of the yarn's weight, preferably between 15% and 25% by weight, more preferably about 20% by weight. 9) Yarn, according to any one of claims 1 to 8, characterized in that the total count of polyester filaments is between 50 and 150 den, preferably between 60 and 120 den, more preferably between 75 and 100 den. 10) Yarn, according to any one of claims 1 to 9, characterized in that said filament core and discontinuous fiber sheath are combined Petition 870250094653, dated 10 / 16 / 2025, page 41 / 48 3 / 5 by means of ring spinning. 11) Textile article, preferably a denim fabric or garment, characterized in that it comprises a yarn, according to any one of claims 1 to 10. 12) A blend of natural cellulosic staple fibers, preferably cotton staple fibers, and regenerated cellulose staple fibers, preferably viscose staple fibers, for a yarn according to any one of claims 1 to 10, characterized in that: the weight ratio of said natural cellulosic fibers to said regenerated cellulose fibers is in the range of 70 / 30 to 80 / 20, preferably this ratio being about 75 / 25; the average length of the fibers in the blend is in the range of 10 to 25 mm, preferably from 12 mm to 20 mm; the 5% index (n) of the fibers in said blend is at least 25 mm, preferably at least 28 mm, more preferably in the range between 28 and 38 mm; the short fiber content SFC(n) of the sheath is at least 35%, preferably at least 40%. 13) Method for the production of a yarn, characterized by comprising the steps of: a. Selecting a filament core, comprising a plurality of polyester filaments; b. Selecting the first fibers which are natural cellulosic fibers; c. Selecting the second fibers which are regenerated cellulosic fibers; d. Providing a discontinuous fiber sheath, Petition 870250094653, dated 10 / 16 / 2025, p.42 / 48 4 / 5 comprising at least 95% by weight of a mixture of said first fibers and said second fibers, wherein the weight ratio of said first fibers to said second fibers is in the range of 70 / 30 to 80 / 20, preferably said ratio being about 75 / 25, wherein the sheath fibers have an average length between 10 and 25 mm, preferably between 12 and 20 mm, wherein the 5%(n) index of the sheath fibers is between 25 mm and 40 mm, preferably between 28 and 36 mm, and wherein the short fiber content SFC(n) of the sheath is between 30% and 70%, preferably between 40% and 60%; and e. combining said filament core and said staple fiber sheath by means of ring spinning. 14) Method according to claim 13, characterized in that the first fibers of the hem are recycled cotton fibers. 15) A method according to any one of claims 13 or 14, characterized in that the polyester filaments are made from recycled polyester. 16) Method for producing a yarn, characterized by comprising the steps of: a. Selecting a filament core, comprising a plurality of polyester filaments; b. Selecting a staple fiber sheath, wherein at least 95% of the sheath is made of first fibers and second fibers, the said first fibers being recycled cotton fibers, the said second fibers being regenerated cellulosic fibers, the weight ratio of said first fibers to said second fibers being in the range of 70 / 30 to 80 / 20, preferably Petition 870250094653, of 10 / 16 / 2025, page 43 / 48 5 / 5, the said ratio being about 75 / 25. c. combining said filament core and said staple fiber sheath by means of ring spinning; 17) Method, according to any one of claims 13 to 16, characterized in that the elongation at break of the polyester filaments of the filament core is in the range of 5% to 15%, preferably between 10% and 12%, when tested with DIN ISO 2062. Petition 870250094653, dated 10 / 16 / 2025, pp. 44 / 48

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