CN118251521A - Filiform core, elastic composite yarn comprising filiform core, fabric comprising filiform core or elastic composite yarn and method for manufacturing filiform core or elastic composite yarn - Google Patents

Abstract

The invention relates to a filiform core (1) for a composite yarn (9) for braiding a fabric, comprising at least one elastic thread (3) and at least one control thread (5, 7); the at least one elastic thread (3) comprises rubber, preferably natural rubber; the at least one control wire (5, 7) comprises a synthetic polymer.

Description

Filiform core, elastic composite yarn comprising filiform core, fabric comprising filiform core or elastic composite yarn and method for manufacturing filiform core or elastic composite yarn

The present invention relates to a filiform core, an elastic composite yarn comprising the filiform core, a fabric comprising the filiform core or the elastic composite yarn and a method for manufacturing the filiform core or the elastic composite yarn.

Elastic composite yarns typically comprise a filiform core comprising one or more elastic filaments and a sheath surrounding the filiform core. The use of filaments made from elastic fibers (also known as spandex or brand name lycra) in the filiform core of elastic composite yarns has become popular due to its excellent elongation properties. However, elastic fiber filaments have poor biodegradability. Accordingly, attempts have been made to find elastic fiber substitutes having higher biodegradability.

For this purpose, WO 2020/0084361 proposes to replace the elastic filaments with a thick core made of rubber. In order to be able to cover the coarse core with a cotton sheath, a hollow spindle spinning machine is proposed. In addition, to prevent inelastic deformation of the yarn, it is proposed to place a supplementary yarn made of natural fabric (e.g. cotton) between the core and the sheath.

However, since hollow spindle spinning machines are not always available in existing factories, it is desirable to provide an at least partially biodegradable filiform core that can be produced and processed by various spinning machines, in particular by ring spinning machines and hollow spindle spinning machines. Furthermore, the inventors have found that there is a need to provide a filiform core that can be produced and/or sheathed with an improved process stability (i.e. reduced risk of failure during manufacturing). Furthermore, it has been found desirable to provide an at least partially biodegradable core with improved elastic recovery.

The object of the present invention is to solve the disadvantages of the prior art, in particular to provide an at least partially biodegradable filiform core, an elastic composite yarn comprising the filiform core, a fabric comprising the filiform core or the elastic composite yarn and a method for manufacturing the filiform core or the elastic composite yarn, wherein the filiform core can be produced using more spinning machines, has improved process stability and/or has improved elastic recovery.

This object is solved by claims 1, 7, 19, 21 and 22.

According to one aspect of the present invention, there is provided a filiform core of elastic composite yarn for use in braiding fabrics. The filiform core comprises at least one elastic filament comprising rubber, preferably natural rubber, and at least one control filament comprising a synthetic polymer.

The at least one elastic filament and the at least one control filament may be interconnected to form a filamentary core. The connection may be achieved through multiple connection points as described in WO 2012/062480A2, which is incorporated herein by reference for the purpose of illustrating how the filaments are connected to each other. For example, the connection may be achieved by mixing or twisting one wire onto another wire or wires. The connection between the filaments may also be accomplished continuously along the filament cores to provide a continuous contact surface between adjacent filaments. At least two filaments may be manufactured separately and transported separately to form a filamentary core. In particular, the filamentary core may be manufactured separately or simultaneously with the manufacture of the filaments thereof. The filiform core may be made simultaneously during the manufacture of the composite yarn or at a previous stage to produce an intermediate product which is introduced into the manufacture of the elastic composite yarn at a second manufacturing stage. In particular, the filiform core may be provided on a spindle or spindle that processes the filiform core into an elastic composite yarn.

The term fibers shall hereinafter contain staple fibers and filaments. A filament is understood to mean in particular a fibrous structure of extremely long or indefinite length. In contrast, staple fibers are understood to mean, in particular, strands (strands) of defined length or short length. In particular, the short length should be a length of at most 500mm, at most 200mm, at most 150mm, at most 100mm, at most 80mm, at most 60mm or at most 45 mm.

In particular, the filaments may be monofilaments or multifilaments. A monofilament is understood to be a single thread of extremely or indefinite length. Multifilament is understood to mean extremely long or indefinite length strands comprising at least two, in particular combined into one filament. In particular, multifilaments with two strands of indefinite length differ from two monofilaments in that they have been combined with one another into an intermediate product prior to being processed into a filiform core or yarn. At least one of the individual strands of the monofilament or at least two strands of the multifilament can in particular be a single strand (one-PIECE STRAND) or a multi-strand (multi-PIECE STRAND). A single segment strand is understood to mean in particular a strand consisting of the entire length of one single segment thereof. For example, individual strands may be produced by melt spinning. In contrast, a multi-segment strand may include a plurality of short strands (or staple fibers) arranged to form strands of extremely long or indefinite length. Hereinafter, the monofilaments implemented as single segment strands will be referred to as single segment monofilaments. Multifilament yarn whose strands are realized as single filaments will be referred to as single-segment multifilament yarn.

Yarn is understood to be, in particular, a collection of numerous filaments and/or staple fibers (which may or may not be textured, spun, twisted or laid together). A composite yarn in the sense of the present invention shall in particular be a yarn comprising staple fibers and/or filaments of at least two different materials, such as polyester filaments surrounded by a sheath of staple fibers made of cotton. Elastic composite yarn is understood to mean in particular a composite yarn comprising at least one elastic filament. Thus, the elastic composite yarn may be, for example, an elastic rubber yarn covered with a cotton sheath. In particular, the elastic composite yarn of the present invention should be used to make fabrics, such as woven or knitted fabrics. The fabric according to the invention should be used in particular for the manufacture of garments, preferably denim.

The term "rubber" as used herein refers to polymers obtainable by polymerization of isoprene monomers. "Natural rubber" as referred to herein is rubber obtained from natural sources (which is obtained preferably without a polymerization step), such as natural rubber (mainly in the form of latex) harvested from rubber trees (bassinet hevea) or other plants.

The elastic filament may comprise at least 50wt.% rubber relative to the total weight of the elastic filament. The elastic filament may comprise at least 60wt.% rubber relative to the total weight of the elastic filament. The elastic filament may comprise at least 70wt.% rubber relative to the total weight of the elastic filament. The elastic filament may comprise at least 80wt.% rubber relative to the total weight of the elastic filament. The elastic filament may comprise at least 90wt.% rubber relative to the total weight of the elastic filament. The elastic filament may comprise at least 95wt.% rubber relative to the total weight of the elastic filament. The elastic filament may comprise at least 98wt.% rubber relative to the total weight of the elastic filament. The elastic filament may comprise at least 99wt.% rubber relative to the total weight of the elastic filament. The elastic filaments may be composed of rubber.

For ease of reading, the elastic filaments containing rubber are also referred to hereinafter as rubber filaments. However, it should be clear that this does not mean that at least one elastic thread must consist purely of rubber.

Preferably, at least one of the rubber filaments is a monofilament, preferably a single segment monofilament. Such monofilaments may be produced, for example, by extruding, especially by extruding, a large amount of natural rubber through a nozzle and curing the natural rubber. Curing may be achieved by well known vulcanization methods. In contrast to the preferred use of rubber filaments as monofilaments, elastomeric filaments (e.g., lycra) are typically used as multifilaments. The inventors of the present invention have found that the use of monofilaments instead of multifilaments unexpectedly improves the process stability when processing rubber filaments (not elastomeric filaments).

Furthermore, it has been found to be advantageous to use rubber filaments having a substantially arcuate cross-section, in particular an elliptical cross-section and/or a circular cross-section. This can be achieved in particular by producing the rubber filaments by extrusion using an annular-opening nozzle through which the filaments are extruded. It has been found that the production of filiform cores and the production of composite yarns is less prone to failure, in other words, can be produced with increased process stability, by replacing the longitudinally cut smooth rubber core used in WO2020/084361A1 with a rubber wire of essentially arcuate cross section. This may be interpreted as that it avoids edge cuts which could lead to accidental entanglement of the rubber filaments with the control filaments (or sheaths) interfering with the spinning process. Furthermore, it has been found that such filaments are not prone to filament breakage which can lead to interruption of the manufacturing process and render the final product useless.

Preferably, at least one control filament is a single segment monofilament or a single segment multifilament. In particular, it has proven advantageous to use single-segment filaments, which stabilize the rubber filaments during spinning, thereby improving process stability. In contrast, a thread composed of short fibers, for example, is less stable in extension of its length in the transverse direction, and therefore is less suitable for stabilizing rubber filaments. Preferably, the at least one control yarn is produced by melt spinning. Melt spinning has the advantage of giving the control filaments a substantially smooth surface, i.e. not as much as, for example, cotton. Preferably, at least one control wire has a substantially circular cross-section, in particular a circular cross-section or an elliptical cross-section.

Within the meaning of the present invention, control filaments are in particular filaments having different material compositions and/or having different material properties (e.g. due to a linear mass density different from that of elastic filaments). In particular, the different material compositions enable the production of a filamentary core combining the advantages of both materials with one product. For example, as described in EP 2145034B1, the combination of elastic and inelastic filaments in a filiform core enables the benefits from both the performance of elastic filaments and inelastic filaments to be obtained, resulting in elastic yarns with improved elastic recovery. Elastic recovery is an important property of elastic yarns because the yarn is able to recover its original length by further releasing the tensile stress after it has been deformed by the first application of the tensile stress. If the recovery properties of the elastic yarn are insufficient or too low, undesirable growth effects may occur. The growth effect is undesirable because the elastic yarn does not provide sufficient elastic recovery to restore the elastic yarn to its original state prior to stressing. Especially considering fabric products, especially pants made of fabric woven from elastic yarns, in highly stressed textile areas (such as the knees and back areas of the pants), the growth effects can cause improper fit (SLAGGY FIT), possibly even rendering the product useless to the consumer. Thus, in order to avoid such a growth effect, the at least one control filament may be realized, for example, with a less elastic (compared to an elastic filament), or even with a non-elastic filament (as defined below). Thus, an at least partially biodegradable core may be provided which benefits from the increased elastic recovery provided by the combination of elastic filaments and less elastic filaments (or inelastic filaments), in particular as described in EP 2145034B 1.

The term "synthetic polymer" as used herein refers to man-made polymers, particularly polymers synthesized by polymerizing one or more monomers under laboratory/industrial conditions. Methods for preparing a variety of synthetic polymers, particularly the specific synthetic polymers mentioned below, are well known in the art.

The control yarn may include at least 50wt.% synthetic polymer relative to the total weight of the control yarn. The control yarn may include at least 60wt.% synthetic polymer relative to the total weight of the control yarn. The control yarn may include at least 70wt.% synthetic polymer relative to the total weight of the control yarn. The control yarn may include at least 80wt.% synthetic polymer relative to the total weight of the control yarn. The control yarn may include at least 90wt.% synthetic polymer relative to the total weight of the control yarn. The control yarn may include at least 95wt.% synthetic polymer relative to the total weight of the control yarn. The control yarn may include at least 98wt.% synthetic polymer relative to the total weight of the control yarn. The control yarn may include at least 99wt.% synthetic polymer relative to the total weight of the control yarn. The control filaments may be composed of synthetic polymers. The inventors have found that the process stability of manufacturing a filiform core and of manufacturing a yarn comprising the core can be improved by supplementing the natural complementary thread known from WO 2020/084361A1 with at least one control yarn according to the underlying invention, including synthetic polymers. One reason for this seems to be that control filaments comprising synthetic polymers may provide a relatively smooth surface compared to, for example, a hairy cotton thread. The hairy nature of the cotton thread appears to lead to an unexpected mixing or sticking with the rubber thread and/or sheath, which may lead to an interruption of the manufacturing process, in particular the spinning process. Further, by using synthetic polymers, the properties of the control filaments and thus of the filiform core can be adjusted over a wide range, so that the filiform core can be used in a larger number of application fields. In particular, the improved elastic recovery can be more precisely tuned by a wide range of polymers and their significantly different properties (e.g., in terms of elasticity, elongation at break and tensile strength).

Preferably, the synthetic polymer is selected from the group consisting of polyesters, polyethylene, polypropylene, polystyrene, polyamides, polyaramides, polyoxymethylene, polytetrafluoroethylene, polyetheretherketone, polyphenylene sulfide, polyalkylene terephthalates (preferably polybutylene terephthalate, polypropylene terephthalate, polyethylene terephthalate (PBT)), copolymers of two or more thereof or mixtures of two or more thereof, preferably polyesters, polyethylene, polypropylene, polystyrene, polyalkylene terephthalates or mixtures of two or more thereof, most preferably polyesters.

It has been found that the combination of polyester (as a synthetic polymer) with rubber filaments is particularly advantageous in providing a filiform core with a desired elastic recovery. In particular, it has been found that polyesters with higher tensile strength and higher elongation at break can increase the elastic recovery of the filiform core and the elastic composite yarn produced therefrom, as compared to, for example, cotton used for complementary yarns in the prior art.

The polyester may be a biodegradable polyester, and in particular may be an aliphatic polyester. Preferably, the polyester is selected from polylactic acid (PLA), polyglycolic acid (PGA), polyepsilon Caprolactone (PCL), polyhydroxybutyrate (PHB), poly (3-hydroxyvalerate), polyethylene succinate (PESu), polypropylene succinate (PPSu), polybutylene succinate (PBSu), polyadipates, copolymers of two or more thereof or mixtures of two or more thereof.

In another embodiment, the polyester may be a copolymer of at least one aliphatic polyester (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyepsilon Caprolactone (PCL), polyhydroxybutyrate (PHB), poly (3-hydroxyvalerate), polyethylene succinate (PESu), polypropylene succinate (PPSu) or polybutylene succinate (PBSu), polyadipate) and at least one aromatic polyester (e.g., polybutylene terephthalate, polytrimethylene terephthalate, polyethylene terephthalate (PBT)).

Preferably, the elastic filaments contain at least 80wt.% cis-1, 4-polyisoprene relative to the total weight of the elastic filaments. Preferably, the elastic filaments contain at least 85wt.% cis-1, 4-polyisoprene relative to the total weight of the elastic filaments. Preferably, the elastic filaments contain at least 90wt.% cis-1, 4-polyisoprene relative to the total weight of the elastic filaments. Preferably, the elastic filaments contain at least 95wt.% cis-1, 4-polyisoprene relative to the total weight of the elastic filaments. Preferably, the elastic filaments contain at least 98wt.% cis-1, 4-polyisoprene relative to the total weight of the elastic filaments. Preferably, the elastic filaments contain at least 99wt.% cis-1, 4-polyisoprene relative to the total weight of the elastic filaments. Preferably, the elastic filaments consist of cis-1, 4-polyisoprene.

Cis-1, 4-polyisoprene may be obtained from plants, preferably selected from the group consisting of: brazil, guianensis, and Benthamiana rubber trees.

Preferably, the elastic filament further comprises one or more of the following: vulcanizing agent, vulcanization accelerator, vulcanization activator, anti-sticking agent, antioxidant and stabilizer.

Preferably, the vulcanizing agent is sulfur. In the rubber of the elastic yarn, sulfur may act as a vulcanizing agent in the form of a sulfur bridge between two different polymer chains of the rubber. The vulcanizing agent may be used in an amount of 0.5wt.% to 5wt.%, preferably 1wt.% to 2.5wt.%, based on the total weight of rubber in the elastic filaments.

The vulcanization accelerator may be a thiazole vulcanization accelerator. The vulcanization accelerator may be used in an amount of 0.1wt.% to 2wt.%, based on the total weight of rubber in the elastic cord.

The vulcanization activator may include or may be a fatty acid, preferably stearic acid. The vulcanization activator may be used in an amount of 0.5wt.% to 15wt.%, preferably 1wt.% to 10wt.%, based on the total weight of rubber in the elastic filaments.

The detackifier may include talc. The antiblocking agent may be used in an amount of 0.5 to 1wt.%, preferably 1 to 5wt.%, based on the total weight of rubber in the elastic filaments.

Preferably, the control wire further comprises a biodegradability enhancing additive. Preferred embodiments of the biodegradability-enhancing additive are described below in the context of other aspects of the invention. Surprisingly, it has been found that the use of a biodegradability enhancing additive does not impair the performance of the control yarn to the extent that the benefits of the above synthetic polymer diminish. Thus, surprisingly, a filamentous core was invented for elastic and control filament biodegradable materials, while maintaining the performance advantages of synthetic polymers.

Another aspect of the invention also relates to a filiform core of elastic composite yarn for knitting fabrics, which can be combined with the previous aspect of the invention (or vice versa). The filamentary core comprises at least one elastic filament. The at least one elastic filament may comprise or consist of a synthetic polymer, in particular may be made of elastic fibers. In particular, the elastic filaments may be lycra filaments. Preferably, however, the at least one elastic filament comprises rubber, preferably natural rubber. In particular, the at least one elastic thread may be realized as at least one elastic thread described in the context of the preceding aspects of the invention.

In addition, the filamentary core comprises at least one control wire comprising a synthetic polymer. The control wire may be implemented as described in the foregoing related aspects of the invention and preferred embodiments thereof. According to this aspect of the invention, at least one control wire is biodegradable. The biodegradability of the control filaments may be achieved, for example, by using a biodegradability enhancing additive and/or by using a self-biodegradable control filament-forming material (e.g. polymer), for example by using a suitable aliphatic polyester (such as those described above).

As mentioned above, it has surprisingly been found that the use of biodegradable control filaments, in particular with biodegradability enhancing additives, does not impair the properties of the synthetic polymer to such an extent that the benefits of the synthetic polymer are lost. In particular, it has been found that biodegradable control filaments comprising synthetic polymers and in particular comprising biodegradability enhancing additives can be advantageously used not only in combination with rubber filaments, but also in combination with synthetic elastic filaments, thereby greatly increasing the field of application of at least partially biodegradable filiform cores.

Preferably, the biodegradability-enhancing additive comprises (or consists of) one or more selected from the group consisting of: starch, a bioaugmentation additive (preferably a microbial strain), a pro-oxidant (preferably a transition metal complex and/or transition metal ion, wherein the transition metal is preferably iron, manganese or cobalt), and a composition comprising 2-hydroxy-3- (trimethylamino) propyl ether.

Preferably, the biodegradability-enhancing additive comprises or consists of starch, or is a composition comprising starch and 2-hydroxy-3- (trimethylamino) propyl ether.

Preferably, at least one elastic thread and/or at least one control thread according to any of the preceding aspects of the invention or embodiments thereof is biodegradable. In particular, the biodegradability of the at least one elastic thread may be provided by using rubber, in particular natural rubber (in particular as described above). The biodegradability of the control filaments may in particular be provided by using a biodegradability enhancing additive as described above or by using a self-biodegradable control filament forming material (e.g. a polymer), for example by using a suitable aliphatic polyester.

Preferably, a biodegradable material in the sense of the present invention shall be a material that is capable of passing ASTM D6400. For purposes of this disclosure, the biodegradability-enhancing additive is suitable for providing biodegradability to a material (e.g., a polymer) that includes an additive that enables the material to pass ASTM D6400.

Additionally, or alternatively, in any of the foregoing aspects of the invention, the at least one control wire is biodegradable in that at least 10%, at least 20%, at least 30%, at least 40%, or at least 45% of the at least one control wire can be biodegraded within 500 days, particularly within 517 days, as measured according to ASTM D5511. In particular, the biodegradation rate measured according to ASTM D5511 for control yarn samples (including polyesters as synthetic polymers) within 517 days was 45.2%. In particular, the following parameters have been measured:

Additionally, or alternatively, in any of the foregoing aspects of the invention, the at least one control wire is biodegradable in that at least 10%, at least 15%, at least 20%, at least 25%, or at least 30% of the at least one control wire can be biodegraded within 500 days, particularly within 507 days, as measured according to ASTM 6691. In particular, the biodegradation rate measured according to ASTM 6691 for control yarn samples (including polyesters as synthetic polymers) within 507 days was 32.4%. In particular, the following parameters have been measured.

It has been found that by adding the above mentioned biodegradability enhancing additives, many different synthetic polymers can achieve the preferred biodegradability described in ASTM D551 and ASTM D6691.

Preferably, the linear mass density of the at least one elastic thread is less than 200dtex, less than 180dtex, less than 160dtex, or less than 140dtex, or less than 130dtex and/or at least 30dtex, at least 40dtex, at least 50dtex, at least 60dtex or at least 70dtex, at least 80dtex, at least 90dtex or at least 100dtex. It is particularly preferred that the linear mass density of the at least one elastic thread is 50dtex to 190dtex, even more preferably 80dtex to 170dtex, most preferably 100dtex to 150dtex. As mentioned above, the at least one elastic filament is preferably a single segment monofilament having a linear mass density within this range. In the case where it is realized as a single-segment multifilament, the sum of the linear mass densities of the multiple single-segment strands of the multifilament may be within this preferred range. For example, in the case of two strands, the linear mass density of each strand is most preferably 50dtex to 75dtex. The same applies to the case where at least one elastic filament comprises, for example, two elastic filaments spun together into a filiform core. For example, in the case where at least two elastic filaments are provided, the sum of the linear mass densities of these at least two elastic filaments may be within the aforementioned preferred range. Thus, each of the at least two filaments may again be realized with a monofilament or a multifilament as described above.

In particular, it has been found that the above linear mass density range enables the elastic filaments to be spun with at least one control filament in a ring spinning machine, in case the at least one elastic filament comprises rubber as described above. Thus, the filiform core can be produced by more spinning arrangements. It has been found that rubber filaments having a density in the above-mentioned range can be produced by extrusion. Thereby realizing two positive effects at the same time. In one aspect, the rubber filaments may be processed in a ring spinning arrangement. On the other hand, for the above reasons, the rubber filaments may be prepared to have a circular cross section, thereby further stabilizing the process.

In less preferred embodiments, the maximum linear mass density of the rubber filaments may be up to 1000dtex, up to 800dtex, up to 600dtex, up to 400dtex, up to 300dtex or up to 250dtex.

Preferably, the linear mass density of the at least one control yarn is at least 20dtex, at least 30dtex, at least 35dtex, at least 40dtex or at least 50dtex and/or at most 500dtex, at most 420dtex, at most 400dtex, at most 300dtex, at most 200dtex or at most 150dtex. It is particularly preferred that the linear mass density of the at least one control yarn is 50dtex to 180dtex, even more preferably 80dtex to 150dtex. Preferably, the at least one control yarn is realized as at least one multifilament yarn, preferably as at least one single-segment multifilament yarn. Preferably, the at least one multifilament yarn comprises 10 to 60, more preferably 20 to 50, most preferably 30 to 40, especially 36 filaments, which together have a preferred linear mass density as defined above. It has been found that the use of control filaments in the preferred ranges described above means a good combination of over filaments (which are not sufficiently thick to stabilize the elastic filaments, especially the rubber filaments, during spinning) and over filaments (which make the process itself prone to failure) during spinning. In this respect it has been found particularly preferred to use two control wires, each of which has the preferred linear mass density described above.

Preferably, at least one elastic filament is elastic in that it is capable of being stretched at least about 2 times its package length and has an elastic recovery of at least 90% to 100% after release from stretching 2 times its package length.

The elastic recovery is a parameter of the elastic properties of at least one elastic filament as described above. The elastic recovery expressed as a percentage represents the ratio of the length of the elastic filament after release of the tensile stress to the length of the elastic filament before the tensile stress was applied (package length). A high percentage (i.e., 90% to 100%) of elastic recovery is believed to provide an elastic ability to return substantially to the original length after application of stress. In this respect, the control wire, which will be mentioned below, is preferably defined by a low percentage of elastic recovery, such that if a stretching of at least twice its original length is achieved, the control wire will not be able to substantially recover to its original length. The percent elastic recovery of the filaments may be tested and measured according to standard astm d 3107, which standard is expressly incorporated herein by reference in its entirety. The test method astm d 3107 is a test method for fabrics made from yarns. Yarn testing methods and testing devices may be used to individually measure filaments and/or yarns. For example, USTERTENSOR RAPID-3 equipment (Uster, switzerland) can measure the elasticity, breaking force, etc. of a yarn or filament. An example of such a test device is described in WO 2012/062480A2, which is incorporated herein by reference.

Additionally or alternatively, an elastic filament within the meaning of the present invention may be understood as a filament having an elongation of at least 150%, at least 180%, at least 210%, at least 230% or at least 260% compared to its package length at a maximum tensile strength according to DIN EN ISO 2062:2010-04. In particular, the average elongation measured for the rubber core in the form of a single-segment monofilament having a linear mass density of 118dtex was 221%. In contrast, the average elongation of Lycra multifilaments with a linear mass density of 78dtex was 261%. In both tests, the average value was calculated based on 20 tests.

Preferably, the at least one control wire is less elastic than the at least one elastic wire, in particular, the control wire cannot be stretched beyond a maximum length that is less than 1.5 times its package length without permanent deformation.

In particular, the lower elastic control yarn provides a safety function that prevents the yarn from being over stretched, thereby avoiding the growth effects described above. Whereby the elastic recovery of the filamentary core can be improved. The use of control filaments comprising synthetic polymers has been found to be particularly advantageous in combination with natural rubber cores, because the elastic/inelastic behavior of the control filaments can be perfectly adjusted to compensate for the difference in elastic behavior of the rubber filaments compared to the elastic filaments. Thus, an at least partially biodegradable filamentary core may be provided which, contrary to the biodegradable cores known in the art, provides similar elongation and recovery properties as the filamentary cores described in EP 2145034 B1 and WO 2016/135211.

In particular, the lower elastic control yarn is less elastic because it cannot be stretched about 1.5, 1.6, 1.7, 1.8, 1.9 or 2 times its package length, while having no elastic recovery of at least 90% up to 100% after a stretch release from 1.5, 1.6, 1.7, 1.8, 1.9 or 2 times its package length.

Preferably, at least one control wire cannot be stretched beyond a maximum length that is less than 1.5 times its original package length without permanent deformation. In this case, the at least one less elastic control yarn may also be referred to as an inelastic yarn. Suitable inelastic control filaments include filaments formed from synthetic polymers (e.g., polyamides, especially nylon 6, nylon 66, PBT, etc.). In addition, polyesters, polyolefins (e.g., polypropylene, polyethylene), and the like, as well as mixtures and copolymers thereof, may also be used. For inelastic control filaments, polyester, nylon or any other composition having the elasticity defined above may be used. For example, elastomeric polyesters or elastomers of two-component elastomeric polyesters (e.g.)。Two different polyesters can be extruded together, produced by Invista.

The at least one control yarn and the at least one elastic yarn are spun into a filiform core by ring spinning or by hollow spindle spinning.

Preferably, the at least one control wire is helically wound around the at least one elastic wire. It has been found that controlling the filaments thereby stabilizes the elastic filaments, which improves the process stability during the manufacture of the filiform core and the subsequent yarn (or fabric). Spiral winding can be achieved in particular by spinning a wire-like core by hollow spindle spinning.

It has been found particularly preferred to use at least two control wires helically wound around or twisted with at least one elastic wire. In particular, at least two control filaments are helically wound around the elastic filament in an alternating manner by hollow spindle spinning, wherein each coil of one control filament is followed in the length direction by a coil of the other control filament. In other words, the two control wires extend in a spiral fashion around the core, wherein the spiral inner diameters of the two control wires are substantially equal. In other words, it is further preferred that at least two control wires both contact the elastic wire, preferably in a spiral contact. Alternatively, the inner control wire may be helically wound around the elastic wire to provide the inner protective coating, and the outer control wire may be helically wound around the inner protective coating to form the outer protective coating. The inner control wire and the outer control wire may be helically wound around the elastic wire in the same direction (or in opposite directions).

It has been found that a particular advantage of using two control wires is that the same elastic wire stability as with one control wire can be achieved without making the resulting core too stiff. This can be explained in particular in that the use of two control wires can increase the number of stable coils per unit length around the elastic wire without having to increase the number of coils per unit length of the control wires, which seems to make the resulting core less stiff.

Preferably, in the unstrained state of the core, at least one control wire extends relatively loosely compared to the elastic wire. This relatively loosely lengthening of the control wire allows the elastic wire to be stretched until the point at which the control wire reaches its elongation limit (i.e., the point at which the relative relaxation of the control wire has disappeared because the control wire is under tension). When the elongation limit is reached, the at least one control wire provides resistance against further elongation, thereby reducing the risk of over-stretching the elastic wire. If the tension on the core is further increased, the core may be further stretched without substantial permanent deformation until a point is reached at which the at least one elastic wire and/or the at least one control wire reaches its elongation limit without substantial permanent deformation as defined above.

The invention also relates to a yarn comprising a filiform core according to one or both of the preceding aspects of the invention. In particular, the filamentary core may be implemented by one or more of the preferred embodiments described above.

The yarn further comprises a fibrous sheath surrounding the filiform core. Preferably, the filiform core and the fibrous sheath are spun into an elastic composite yarn by ring spinning or core spinning. The fibrous sheath may comprise short fibers and/or filaments. Preferably, the fibrous sheath is comprised of at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100% staple fibers.

In particular, the fibrous sheath may comprise cellulosic fibers and/or synthetic fibers (filaments and/or staple fibers). In particular, cellulose fibres made from ethers or esters of cellulose (which may be obtained from the bark, wood or leaves of plants or from other plant-based materials). In addition to cellulose, the fibers may include hemicellulose and lignin, among others. In particular, the cellulose fibers may be natural cellulose fibers or man-made (regenerated) cellulose fibers. For example, natural cellulose fibers in the form of cotton fibers, silk fibers and/or linen fibers may be used. In particular, man-made cellulose fibers are produced by pulping plants and then extruding the pulp in the same manner as synthetic fibers (e.g., polyester or nylon). For example, the man-made cellulose fibers may be used in the form of rayon, lyocell (tencel), modal, and/or viscose fibers. In particular, synthetic fibers are fibers that have been manufactured by chemical synthesis. Typically, synthetic fibers and/or filaments are produced by extruding a fiber-forming material through a spray head into air and water to form the fibers. Synthetic fibers can be made, for example, from crude oil and intermediates including petroleum, coal, limestone, and water. As synthetic fibers, for example nylon fibers, polyester fibers, acrylic fibers, spandex fibers, aramid fibers, T400 and/or glass fibers may be used.

Particularly preferably, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100% of the fibers are biodegradable fibers, in particular biodegradable fibers capable of passing ASTM D6400 as described above. In particular, the amount of fiber may be selected from, for example, cotton, wool, silk, flax, hemp, jute, sisal, raffia, ramie, and linen. In particular, if the core is composed of biodegradable fibers (e.g., elastic rubber filaments and at least one biodegradable control filament), the integral yarn can be biodegradable. Additionally or alternatively, the sheath may comprise or consist of synthetic fibers (e.g., polyester).

Preferably, the elastic composite yarn is colored, in particular with indigo. In particular, the elastic composite yarn is ring dyed, in particular by vat dyes.

Preferably, the linear mass density of the fibrous sheath is at least 3Ne, at least 3.5Ne, at least 4Ne, at least 5Ne, at least 6Ne, at least 8Ne or at least 10Ne and/or is at most 80Ne, at most 60Ne, at most 55Ne, at most 50Ne, at most 40Ne, at most 30Ne or at most 20Ne. Particularly preferably, the linear mass density is 4Ne to 55Ne, more preferably 6Ne to 40Ne, most preferably 8Ne to 30Ne or 10Ne to 20Ne.

The invention also relates to a fabric comprising a filiform core and/or yarn as described above. Preferably, the fabric is a woven fabric. In particular, the yarn is used as at least one warp and/or at least one weft yarn in a woven fabric, in particular at least 10%, at least 25%, at least 50%, at least 75% or 100% of the warp and/or weft yarns. Preferably, the fabric is a jean fabric. In particular, the fabric is an indigo-dyed denim fabric.

Another aspect of the invention relates to a method for making a filiform core or elastic composite yarn. In particular, the method may be carried out by producing a filiform core and/or an elastic composite yarn as described above. Furthermore, the filiform core and/or the elastic composite yarn can be designed such that it can be produced with the method of the invention.

The method comprises the step of spinning at least one elastic yarn and at least one control yarn comprising a synthetic polymer, in particular ring spinning or hollow spindle spinning, into a filiform core.

Those skilled in the art know how to perform ring spinning and hollow spindle spinning, and how to distinguish between filiform cores made by ring spinning and cores made by hollow spindle spinning. In particular, when ring spinning is used, at least one elastic yarn and at least one control yarn are combined and then twisted in the S-direction or Z-direction by a ring runner system of a ring spinning machine. Whereby both the at least one elastic filament and the at least one control filament are twisted. By spinning using a hollow spindle, the at least one control yarn can be helically wound around the at least one elastic yarn, in particular without twisting the at least one elastic yarn.

In particular, hollow spindle spinning may be performed as disclosed in WO2020/084361A1, which is incorporated herein by reference. In particular, hollow spindle spinning can be achieved as described in WO2020/084361 in fig. 1 and 2, in which the elastic fiber used is replaced by at least one of the aforementioned at least one elastic yarn and the covering yarn described therein is replaced by at least one of the aforementioned at least one control yarn. In particular, at least one control yarn is helically wound around at least one elastic yarn by hollow spindle spinning.

In particular, synthetic polymers may be selected as described above. According to an alternative of this aspect of the invention, the at least one elastic filament comprises rubber, preferably natural rubber. In particular, a rubber core, in particular a rubber core of a material and/or linear mass density as described above, can be selected. According to a second option of this aspect of the invention (which may be combined with the preceding option), at least one control wire is biodegradable. Biodegradability may be achieved by using a biodegradability enhancing additive, which may be selected as described above; and/or by using a material (such as a polymer) that is itself biodegradable to form the control filaments, such as by using a suitable aliphatic polyester, such as those described above.

Preferably, during spinning, at least one elastic yarn is drawn at a draw ratio of 1.5 to 5.0, more preferably 1.9 to 4.2, most preferably 2.5 to 3.5. Additionally or alternatively, the control filaments are drawn in the range of 1.0 (i.e., no draw) to 1.2, more preferably 1.05 to 1.15, most preferably 1.07 to 1.12. Additionally or alternatively, the draw ratio of the at least one elastic filament is preferably at least 0.3, at least 0.5, at least 0.7, at least 1.0, at least 1.2, or at least 1.5 greater than the draw ratio of the at least one control filament.

In particular, the draft ratio is the ratio of the length of the raw yarn strand fed from its package to the length of the yarn strand delivered from the spinning machine. Thus, a draft ratio greater than 1.0 is a measure of the reduction in volume and weight of the raw silk strands. In particular, the package length is the length of the tensioned filaments or yarns forming the same package.

Preferably, the at least one control yarn and the at least one elastic yarn are spun (in particular ring spun or hollow spindle spun) in such a way that: after the spinning process, the at least one control yarn has a length remaining compared to the at least one elastic yarn, in other words, the at least one elastic yarn is in a relatively low state. Thus, between the initial draw and up to a certain point of draw, the filamentary core is drawn while only the elastic filaments and not the control filaments provide a restoring force. After this point, the control wire becomes active in providing a restoring force, thereby protecting the core from over-stretching and the resulting unwanted growth. This relatively relaxed state of the at least one control yarn can be achieved in particular by selecting the respective draw ratio difference (for example as described above) in combination with the respective rotational speed of the spinning arrangement.

Preferably, the method further comprises the step of spinning (especially ring spinning) the fibrous sheath around the filiform core. In particular, the fibrous sheath is designed as described above. Preferably, the fibrous sheath is spun around the filiform core by core-spun spinning. Core spun yarns comprise, inter alia, introducing a filiform core into a stream of staple fibers such that the staple fibers of the resulting yarn more or less cover the filiform core.

In particular, the filiform core is produced in a first step and surrounded by a fibrous sheath in a second step. For example, in a first step a filiform core is produced by hollow spindle spinning and in a second step a fibrous sheath is covered around the filiform core by core spun yarn.

Or the filiform core and the fibrous sheath surrounding the filiform core may be realized in one step. For example, at least one elastic filament and at least one control filament may be combined and transferred together into the middle of the sliver, which is then spun around the two filaments by core spun yarn to form a filiform core and a fibrous sheath surrounding the filiform core in one step.

Other aspects, features, and characteristics of the present invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, in which:

Fig. 1: schematic representation of a filiform core produced by hollow spindle spinning;

fig. 2: schematic representation of an elastic composite yarn comprising the filiform core of fig. 1;

fig. 3: schematic representation of an alternative filiform core produced by hollow spindle spinning;

fig. 4: schematic representation of a filiform core produced by ring spinning;

Fig. 5: schematic illustration of spinning S twist in an elastic yarn into a filiform core by ring spinning; and

Fig. 6: schematic illustration of spinning Z-twist in an elastic yarn into a filiform core by ring spinning.

In fig. 1, a filiform core 1 produced by hollow spindle spinning is shown, wherein the elastic filaments are indicated with reference number 3. In the embodiment of fig. 1, the at least one control wire comprises two control wires denoted by reference numerals 5 and 7. In the illustrated embodiment, the elastic filaments 3 and the control filaments 5 and 7 are each single-segment monofilaments.

Two control filaments 5, 7 are helically wound around the elastic filament 3, thereby forming a core-stabilizing protective layer (coat) for further processing into yarns and for further processing of yarns into fabrics. In fig. 1, at least two control wires 5, 7 are wound around the elastic wire 3 in an alternating manner, wherein each coil 5C of one control wire 5 is followed in the length direction by a coil 7C of the other control wire 7. In other words, the two control wires 5, 7 extend in a spiral manner around the core 4, wherein the spiral inner diameters of the two control wires are substantially equal. In other words, it is also preferred that both control wires 5, 7 contact the elastic wire in a spiral contact.

Fig. 3 schematically shows an alternative embodiment of a filiform core produced by hollow spindle spinning, wherein an inner protective layer is formed by an inner control wire 5 helically wound around an elastic wire 3 and an outer protective layer is formed by an outer control wire 7 helically wound outside the inner protective layer. In the embodiment shown in fig. 3, the inner control wire 5 is helically wound in a counter-clockwise direction and the outer control wire 7 is helically wound in a clockwise direction. In an alternative embodiment (not shown), the inner control wire 5 may be helically wound in a clockwise direction and the outer control wire 7 may be helically wound in a counter-clockwise direction. In a further embodiment (not shown), both control wires 5, 7 may be helically wound in the same direction.

Fig. 4 is intended to schematically show the difference between a filiform core 1 produced by ring spinning (as shown in fig. 1 and 3) and a filiform core produced by ring spinning (as schematically shown in fig. 4). Hollow spindle spinning provides the filiform core 1 with a protective layer helically surrounding the loops 5c, 7c of the elastic filaments 3, whereas ring spinning provides the filiform core in which both the elastic filaments and the control filaments 5 are twisted relative to each other about a twisting axis (dashed line in fig. 4). Depending on the materials used for the elastic yarn 3 and the control yarn 5 and the spinning parameters, the yarn 3, 5 may shrink to a different extent after spinning, whereby one yarn may be stretched more loosely than the other. In fig. 4, an embodiment is shown in which the elastic yarn 3 is contracted more strongly after spinning, leaving the control yarn 5 with a length remaining, in other words, the control yarn 5 is in a relatively relaxed state compared to the elastic yarn. In fig. 4, the elastic thread 3 is not completely straight but slightly helically twisted as a result of the ring spinning operation.

Another distinction between a threadlike core 1 spun by a hollow spindle and a threadlike core spun by a ring can be seen from the twisting of the elastic filaments 3. In particular, when ring spinning is used, at least one elastic yarn 3 and at least one control yarn 5 are combined and then twisted in the S direction (fig. 5) or the Z direction (fig. 6) by a ring runner system of a ring spinning machine. Thereby, both the at least one elastic filament 3 and the at least one control filament 5 are twisted. As schematically shown in fig. 5 and 6, even if the elastic yarn 3 is completely contracted into a straight yarn after spinning, the elastic yarn is twisted around its own longitudinal axis (indicated by oblique lines in the elastic yarn 3 in fig. 5 and 6). In contrast, when spinning using a hollow spindle, the elastic yarn 3 is not twisted. Further, as shown by S and Z in fig. 5 and 6, when ring spinning is used, the control yarn 5 twisted with the elastic yarn 3 will be twisted in the same direction as the elastic yarn 3.

Fig. 2 shows an exemplary embodiment of an elastic composite yarn 9 comprising the filiform core 1 shown in fig. 1 and a sheath 11 of staple fibers surrounding the filiform core 1, wherein the sheath 11 is spun around the core by core spun yarn.

The features disclosed in the above description, in the drawings and in the claims may be essential for the implementation of the invention in different embodiments alone and in any combination.

Reference numerals:

1 filiform core

3 Elastic yarn

5. 7 Control wire

5C control wire 5 coil

7C coil of control wire 7

9 Composite yarn

Claims (22)

1. A filiform core (1) for a composite yarn (9) for braiding a fabric, comprising:

-at least one elastic thread (3), said at least one elastic thread (3) comprising a rubber, preferably a natural rubber, and

-At least one control wire (5, 7), said at least one control wire (5, 7) comprising a synthetic polymer.

2. The filiform core (1) of claim 1, wherein the synthetic polymer is selected from the group consisting of: polyesters, polyethylenes, polypropylenes, polystyrenes, polyamides, polyaramides, polyoxymethylene, polytetrafluoroethylene, polyetheretherketone, polyphenylene sulfide, polybutylene terephthalate, polyalkylene terephthalates, preferably polybutylene terephthalate, polypropylene terephthalate, polyethylene terephthalate (PBT), copolymers of two or more thereof or mixtures of two or more thereof; preferably polyester, polyethylene, polypropylene, polystyrene, polyethylene terephthalate or a mixture of two or more thereof; most preferred is polyester.

3. The filiform core (1) according to claim 2, wherein the polyester is an aliphatic polyester.

4. The filiform core (1) according to one of the preceding claims, wherein the elastic filaments (3) contain at least 80wt.% of cis-1, 4-polyisoprene relative to the total weight of the elastic filaments (3).

5. The filiform core (1) according to one of the preceding claims, wherein the elastic thread (3) further comprises one or more of the following: vulcanizing agent, vulcanization accelerator, vulcanization activator, anti-sticking agent, antioxidant and stabilizer.

6. The filiform core (1) according to one of the preceding claims, wherein the control filaments (5, 7) further comprise a biodegradability enhancing additive.

7. Filiform core (1), in particular a filiform core (1) of a composite yarn for braiding fabrics according to one of the preceding claims, comprising:

-at least one elastic thread (3), and

-At least one biodegradable control wire (5, 7), said control wire (5, 7) comprising a synthetic polymer.

8. The filiform core (1) according to claim 7, wherein the at least one biodegradable control filament comprises a biodegradability enhancing additive, and/or wherein the synthetic polymer is an aliphatic polyester.

9. The filiform core (1) according to one of claims 6 or 8, wherein the biodegradability-enhancing additive comprises one or more selected from the group consisting of: starch; a bio-enhancing additive, preferably a microbial strain; an oxidation promoter, preferably a transition metal complex and/or a transition metal ion, wherein the transition metal is preferably iron, manganese or cobalt; and compositions comprising 2-hydroxy-3- (trimethylamino) propyl ether.

10. The filamentous core (1) according to any of claims 6, 8 or 9, wherein the biodegradability enhancing additive comprises starch, preferably a composition comprising starch and 2-hydroxy-3- (trimethylamino) propyl ether.

11. The filiform core (1) according to one of the preceding claims, wherein the at least one elastic thread (3) and/or the at least one control thread (5, 7) are biodegradable, in particular having biodegradability by ASTM D6400.

12. The filiform core (1) according to any of the preceding claims, wherein the linear mass density of the at least one elastic thread (3) is less than 200dtex, less than 180dtex, less than 160dtex, or less than 140dtex, or less than 130dtex, and/or is at least 30dtex, at least 40dtex, at least 50dtex, at least 60dtex, or at least 70dtex, at least 80dtex, at least 90dtex, or at least 100dtex.

13. The filiform core (1) according to any of the preceding claims, wherein the linear mass density of the at least one control filament (5, 7) is at least 20dtex, at least 30dtex, at least 35dtex, at least 40dtex or at least 50dtex and/or is at most 500dtex, at most 420dtex, at most 400dtex, at most 300dtex, at most 200dtex or at most 150dtex.

14. The filiform core (1) according to any of the preceding claims, wherein the at least one elastic filament (3) is elastic in that it is capable of being stretched at least about 2 times its packaging length and has an elastic recovery of at least 90% to 100% after release from stretching 2 times its packaging length.

15. The filiform core (1) according to any of the preceding claims, wherein the elasticity of the at least one control wire (5, 7) is smaller than the elasticity of the elastic wire, in particular the at least one control wire (5, 7) cannot be stretched beyond a maximum length without permanent deformation, the maximum length being smaller than 1.5 times its packaging length.

16. The filiform core (1) according to one of the preceding claims, wherein the at least one control filament and the at least one elastic filament are spun into the filiform core by ring spinning.

17. The filiform core (1) according to one of the preceding claims, wherein the at least one control filament and the at least one elastic filament are spun into the filiform core by hollow spindle spinning.

18. The filiform core (1) according to any of the preceding claims, wherein the at least one control wire (5, 7) is helically wound around the at least one elastic wire (3); in particular, wherein the at least one control wire (5, 7) comprises at least two control wires (5, 7) helically wound around the at least one elastic wire (3).

19. An elastic composite yarn (9) comprising:

-a filiform core (1) according to any of the preceding claims, and

-A fibrous sheath (11) surrounding said filiform core (1),

In particular, wherein the filiform core and the fibrous sheath are spun into the elastic composite yarn by ring spinning or core spun spinning.

20. The elastic composite yarn (1) according to claim 19, wherein the linear mass density of the sheath is at least 3Ne, at least 3.5Ne, at least 4Ne, at least 5Ne, at least 7Ne or at least 10Ne, and/or is at most 80Ne, at most 60Ne, at most 55Ne, at most 50Ne, at most 30Ne or at most 20Ne.

21. A fabric, in particular a woven fabric such as a jean fabric, comprising: the filiform core (1) of any of claims 1 to 18, or the elastic composite yarn (9) of claim 19 or 20.

22. A method for manufacturing a filiform core (1), in particular for manufacturing a filiform core (1) according to one of claims 1 to 18, or a method for manufacturing an elastic composite yarn (9), in particular for manufacturing an elastic composite yarn (9) according to one of claims 19 or 20, comprising the steps of:

-spinning, in particular ring spinning or hollow spindle spinning, at least one elastic yarn (3) and at least one control yarn (5, 7) comprising a synthetic polymer into a filiform core (1), wherein the at least one elastic yarn (3) comprises rubber, preferably natural rubber; and/or the at least one control wire is biodegradable; and optionally the steps of:

-spinning, in particular ring spinning or core spun spinning, a fibrous sheath (11) around the filiform core (1) to obtain an elastic composite yarn (9).