Method for manufacturing improved elastic fabrics and elastic fabrics thus manufactured

Abstract

To manufacture an elastic fabric, the method includes the following steps: manufacturing a wound yarn (50), wherein the core yarn (30) and the winding yarn (40) are preferably and independently selected from: man-made fibers, such as rayon; natural fibers, such as flax, hemp, ramie, bamboo, jute, cotton, wool, silk; and synthetic fibers, such as nylon, polyester, acrylic, etc.; tensioning the core yarn (30) with a predetermined tension; conveying the core yarn (30) and the winding yarn (40) such that the latter laterally reaches the former in a winding space (35), selecting the conveying speed; and winding the winding yarn (40) in the winding space (35). Around the core yarn (30), such that during winding, in the wound yarn (50), the core yarn (30) and the winding yarn (40) are twisted in corresponding twisting directions opposite to each other, and the winding yarn (40) forms a number of turns T per unit length of the wound yarn (50) that is higher than a predetermined minimum number of turns T0 of the wound yarn (40) and lower than a predetermined maximum number of turns T1 of the wound yarn (40), the minimum number of turns and the maximum number of turns depending on the second linear mass density Nm; the fabric is manufactured by a knitting process or a weaving process; the yarn (50) and / or the fabric is washed.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing elastic fabrics that are easier to handle than conventional elastic fabrics, and to elastic fabrics manufactured by such method.

[0002] In particular, the present invention relates to a method for manufacturing a biodegradable fabric composed of a biodegradable material, which may be treated, for example, by composting, and to an elastic fabric manufactured by such method.

[0003] The present invention also relates to elastic yarns for manufacturing such fabrics.

[0004] Reference to existing technology - technical issues

[0005] For decades, elastic fabrics made from various elastic yarns have been used. The advantage of these fabrics lies in the high deformability of the items made from them. In particular, clothing is manufactured to not restrict the wearer's movement or to adapt to these movements, thus providing comfort. This is especially popular in underwear, sportswear, and fitness apparel, but also in everyday situations such as sitting in a car, walking, and whenever joints must bend. Furthermore, elastic fabrics are used to manufacture bandages, dressings, and clothing for treating wounds, sprains, groin hernias, etc. Additionally, elastic fabrics are advantageous for manufacturing general-purpose gloves and overlays for sofas, armchairs, and chairs, as round overlays can be easily made from them.

[0006] Currently available elastic fabrics are characterized by the high elasticity of the elastic yarns used to manufacture them. The elasticity of the elastic yarns, in turn, depends on the combination of core elastomer fibers and core-spun yarns, which are wound around the core elastomer fibers or formed into loops and can be composed of various textile materials.

[0007] For example, documents WO 2008 / 130563 A1 and WO 2012 / 062480 A2 describe ring-spun elastic composite yarns, in which elastic core-spun filaments made of synthetic elastomer materials are surrounded by fiber sheaths composed of a large number of synthetic or natural short fibers (e.g., cotton fibers). Other elastic yarns, such as those described in WO 2012 / 056436 and WO 2019 / 159155, are obtained by a winding machine, in which substantially non-extensible yarn is wound around elastic core-spun filaments made of synthetic elastomer materials to form a helix or spiral around the elastic yarn. By applying tension to the elastic yarn obtained in this way, the turns of the spiral formed around the core move away from each other, and by continuously releasing the tension, the turns and the spiral tend to return to their initial conformation. This behavior allows for the elastic recovery of the elastic yarn and the fabrics made from it.

[0008] In the aforementioned existing elastic products, the use of core elastic fibers made of synthetic elastomer materials has drawbacks.

[0009] First, these fabrics comprise both elastomer and fibrous portions of various materials. This non-uniformity makes products made from these fabrics difficult to recycle when discarded, as the two types of materials must be recycled separately using specific technologies.

[0010] Furthermore, even if the fiber sheath or the non-stretchable yarn wound around the core is made of natural, biodegradable materials such as flax, hemp, ramie, bamboo, jute, cotton, wool, and silk, the presence of the synthetic elastomer portion—the non-biodegradable portion—ruins that precludes composting as a possible treatment method for clothing and similar textiles made from the relevant fabrics. This would be one of the most preferred, inexpensive, and environmentally friendly treatment methods known to date for such items. In short, the aforementioned elastic fabrics are virtually unsustainable environmentally and do not meet the requirements of a circular economy.

[0011] To address this issue, WO 2020 / 084361 describes an elastic yarn with the same structure as in WO 2012 / 056436, wherein the elastomer core is made of natural rubber and the substantially non-stretchable yarn wound around the natural rubber core is based on cotton. Summary of the Invention

[0012] Therefore, one object of the present invention is to provide a method for manufacturing elastic fabrics having a uniform structure (i.e., a structure formed from materials that can be processed by the same process), thereby simplifying the recyclability of clothing and similar products made from such elastic products.

[0013] A specific object of the present invention is to provide a method different from existing techniques for manufacturing fully biodegradable elastic fabrics that, once discarded, can be disposed of by composting garments made from them.

[0014] Another object of the present invention is to provide a method for manufacturing an elastic fabric that provides a comfortable and cool feel to the user as needed, especially in the case of summer clothing.

[0015] According to a first aspect of the invention, these and other objectives are achieved by a method for manufacturing an elastic fabric, the method comprising the following steps:

[0016] - To form a wound yarn, the following steps are included:

[0017] -Pre-arranged with a first linear mass density Nm c Core yarn:

[0018] -Pre-arranged with a second linear mass density Nm set between 1 and 120 km / kg w The winding yarn, wherein the winding yarn is twisted in an initial twisting direction selected between "Z" and "S",

[0019] The core yarn is twisted in the same initial twisting direction as the winding yarn;

[0020] - Apply a predetermined tension to the core yarn;

[0021] - The core yarn and winding yarn are conveyed toward the collection bobbin of the wound yarn (51) at a corresponding conveying speed.

[0022] The conveying step is performed such that the winding yarn laterally reaches the vicinity of the core yarn in the winding space;

[0023] - In the winding space, the winding yarn is wound around the core yarn, such that during the winding step, the winding yarn is twisted in a final twisting direction opposite to the initial twisting direction, i.e., in separate twisting directions.

[0024] Twisting is performed in the final twisting direction chosen between "S" and "Z";

[0025] - Obtain the wound yarn on the collecting bobbin;

[0026] - Fabrics are formed from wound yarns by choosing a fabric manufacturing process between knitting and weaving processes;

[0027] The method includes a step of washing the fabric and / or a step of washing the wound yarn.

[0028] The washing steps selected between them, among which

[0029] -The core yarn is a non-elastic yarn;

[0030] - A winding step is performed to form a series of loops around the core yarn, the loops having a pitch longer than the diameter of the winding yarn, so that free space is left between the loops;

[0031] - The tension applied to the core yarn is lower than the minimum predetermined force value, and the minimum predetermined force value is selected so that...

[0032] The core yarn forms a series of ridges protruding between free spaces.

[0033] - Select a conveyor speed so that, during the winding step, each unit length of the wound yarn is wound.

[0034] A number of turns T that is higher than the predetermined minimum number of turns T0 of the winding and lower than the predetermined maximum number of turns T1 of the winding.

[0035] The minimum number of turns T0 and the maximum number of turns T1 depend on the second linear mass density Nm w ,

[0036] Among them, the second linear mass density Nm indicated in the corresponding row of the table below w Each value

[0037] <![CDATA[Nm w ]]> <![CDATA[T0]]> <![CDATA[T1]]> 1 20 50 2 40 500 3 60 600 10 150 1000 20 200 1300 30 250 1400 40 300 1500 50 300 1600 70 400 1700 90 500 1800 120 600 2000

[0038] The minimum number of turns T0 and the maximum number of turns T1 are the numbers written into the corresponding rows of the table and the columns starting with T0 and T1, respectively.

[0039] In this specification, the term “winding” can refer to a very loose winding construction in which there is a wide space (pitch) between subsequent turns; or a tighter construction in which the space is narrower, as long as some space is left between subsequent turns.

[0040] The number of turns per meter of wound yarn refers to the number of reverse turns that must be received from a segment of wound yarn of a predetermined length in order to completely remove the turns therefrom, the yarn being arranged between two fixed ends and having a predetermined initial tensile strain. Specifically, the predetermined length and tensile strain are selected according to ISO Rule 2061.

[0041] Therefore, through the washing step, the wound yarn is shrunken, causing the ridge of the core yarn to be compressed between the turns of the winding yarn, resulting in the wound yarn incorporated into the fabric becoming elastic, and thus also causing the fabric itself to become elastic, which is a completely unexpected result.

[0042] Since the winding step is performed by reversing the twisting direction of the winding yarn, the winding yarn and the core yarn will have opposite twisting directions in the winding yarn.

[0043] Specifically, because the two yarns forming the structure of the wound yarn, namely the core yarn and the winding yarn, are twisted in opposite directions within the wound yarn—that is, they are Z-twisted and S-twisted, or S-twisted and Z-twisted, respectively—the shrinking wound yarn has internal opposing reaction forces between the winding yarn and the core yarn after the washing step. This results in inherent elasticity, allowing the fabric to perform elastic recovery when stretched and then released.

[0044] For the same reason, wound yarn will inherently resist any further twisting. Therefore, in the case of wound yarn with the core and winding yarns having the same twist direction, especially if the wound yarn is intended to be used to make a fabric by knitting, it will be more difficult to obtain a balanced fabric. Articles made from such fabrics will have improved dimensional stability and regularity.

[0045] Furthermore, because the turns of the wound yarn are spaced apart from each other, there are full and empty areas side by side in the fabric. This reduces friction between the wearer's skin and the garment made from the fabric manufactured according to the invention, which facilitates the exchange of physiological heat and moisture between the wearer and the environment, in short, providing a cool touch, which is uncommon for currently available elastic fabrics. Therefore, the fabric manufactured using the method according to the invention is advantageously suited for manufacturing summer clothing.

[0046] As is common in commercially available yarns, the pre-arranged winding yarn can have an initial "Z" twist direction, and the winding process is performed in either a clockwise or counterclockwise direction, such that the wound yarn is twisted in the opposite direction while being wound around the core yarn until its initial "Z" twist direction is completely released and it is twisted in the opposite "S" twist direction, until the final twist is achieved, depending on the final number of turns formed around the core yarn. Alternatively, the pre-arranged winding yarn can have an initial "S" twist direction, and the winding process is performed such that the wound yarn is twisted in the opposite direction while being wound around the core yarn until its initial "S" twist direction is completely released and it is twisted in the opposite "Z" twist direction, until the final twist is achieved, depending on the final number of turns formed around the core yarn. Conversely, if the winding step is performed by increasing the twist in the initial "Z" or "S" twist direction, the resulting winding will be too "tight" to allow any elasticity to be generated in the wound yarn, or the wound yarn will quickly become tight enough to break before forming the required number of loops around the core yarn.

[0047] As is well known, the linear mass density of yarn or filament is Nm (here, Nm). c and Nm w This corresponds to a length in kilometers of 1 kg of yarn or filament, and can therefore be expressed in km / kg. In particular, the winding and core yarns have linear mass densities set independently between 1 km / kg and 120 km / kg.

[0048] Preferably, the tension F applied to the core yarn is higher than a predetermined minimum force F0. Poor tension in the core yarn will make it virtually impossible for the winding yarn to wind around the core yarn. Furthermore, the tension applied to the core yarn must exceed the minimum value to ensure uniform characteristics of the wound yarn obtained from multiple winding units of the same winding machine. The predetermined minimum force depends on the linear mass density of the core yarn.

[0049] Specifically, the first linear mass density value Nm c Set between 1 and 120 km / kg, for each first linear mass density value Nm indicated in the corresponding row of Table 1. c The minimum force F0 is equal to the force value in grams written in the same row of Table 1, while the first linear mass density Nm indicated in the corresponding adjacent row of Table 1 is...c The minimum force F0, which is the intermediate value between two adjacent values, can be obtained by linear interpolation of the force values ​​F0 written in the same adjacent row of Table 1.

[0050]

[0051] According to the invention, as anticipated, the tension F applied to the core yarn is lower than a predetermined maximum force F1. If the tension applied to the core yarn exceeds the aforementioned maximum force value, the core yarn will remain rigid and linear during and after the winding step, instead of forming ridges as previously described. Therefore, the wound yarn obtained under these conditions, or the fabric made therefrom, cannot exhibit elasticity when stretched. For the same reason, the aforementioned spacing effect of the ridges on the turns of the wound yarn will disappear, and the low friction and high heat and moisture transfer properties of the fabric will be lost, along with the comfortable and cool feel provided to the wearer of garments made from such fabric.

[0052] Specifically, for each first linear mass density value Nm indicated in the corresponding row of Table 2 c The maximum force F1 is equal to the force value in grams (F1) written in the same row of Table 2. Specifically, for the first linear mass density Nm indicated in the corresponding adjacent row of Table 2... c The intermediate value between two adjacent values ​​is used to obtain the maximum force F1 by linear interpolation of the force values ​​F1 written in the same adjacent row of Table 2.

[0053] According to the present invention, as described above, during the winding step, the conveying speeds of the core yarn and the winding yarn are selected such that the number of turns T per unit length of yarn is higher than a predetermined minimum number of turns T0.

[0054] Specifically, for each second linear mass density value Nm indicated in the corresponding row of Table 3 w The minimum number of turns T0 is equal to the number T0 written in the same row of Table 3. Specifically, for the second linear mass density Nm indicated in the corresponding adjacent row of the table... w The intermediate value between two adjacent values ​​is determined by comparing the number T in the same adjacent row of Table 3. O Perform linear interpolation to obtain the minimum number of turns T. O .

[0055]

[0056] Preferably, during the winding step, the feed speed of the core yarn and the winding yarn is selected such that the number of turns T per unit length of yarn is lower than a predetermined maximum number of turns T1. If the number of turns of the wound winding yarn exceeds the aforementioned maximum number, the portion of the core yarn protruding between the corresponding pairs of turns between any two adjacent ridges will be too short to allow the overall elongation / elastic recovery of the wound yarn during stretching / releasing, and therefore the wound yarn and the fabric made from it will have poor elasticity even after a washing step. Furthermore, if too many turns are wound around the core yarn, the aforementioned spacing effect of the ridges on the turns of the wound yarn will disappear, and the low friction and high heat and moisture transfer properties of the fabric will be lost, along with the comfortable and refreshing feel provided to the wearer of clothing made from such fabric.

[0057] Specifically, for each second linear mass density value Nm indicated in the corresponding row of Table 4 w The maximum number of turns T1 is equal to the number T1 written in the same row of the table, while the second linear mass density Nm is indicated in the corresponding adjacent row of the table. w The intermediate value between the two values ​​is used to obtain the maximum number of line turns T1 by linear interpolation of the number T1 in the same adjacent rows written in Table 4.

[0058] Preferably, the washing step includes a step of washing the fabric in water in a flat or rope manner, and in particular, the washing step is carried out under conditions and for a washing time where the fabric shrinks by 15% to 30%.

[0059] Advantageously, the core yarn and winding yarn are made independently of each other from natural or synthetic fibers, or a combination of natural and synthetic fibers. Without the use of synthetic fibers such as nylon, polyester, and acrylic fibers, the fabrics and articles made from them are more likely to degrade through environmental exposure, particularly through composting. Specifically, the natural fibers used to manufacture the wound yarn can be selected from the group consisting of: flax; hemp; ramie; bamboo; jute; cotton; wool; silk; and combinations thereof. Specifically, the synthetic fibers used to manufacture the wound yarn can be selected from the group consisting of: rayon, Tencel, lyocell, milk fiber, orange fiber, nettle fiber, kapok fiber, all biodegradable materials, and combinations thereof.

[0060] In particular, the core yarn and the winding yarn have the same composition. In this way, based on a formula of one material, the resulting fabric is completely uniform and can be handled even more easily.

[0061] Specifically, the winding is a discontinuous yarn, and the winding space is a protected space enclosed within a container. This is the case for natural fibers and most synthetic fibers such as rayon. It is well known that the cohesive force between fibers, and therefore the resistance of the discontinuous yarn made from them, is primarily provided by the friction between the winding and the air during the twisting process. By the method described above, the discontinuous winding, after losing its initial twisting direction (e.g., "Z"), and before twisting in the opposite final twisting direction (e.g., "S"), is in an untwisted state where the cohesive force of the discontinuous fibers forming the yarn is very poor or nonexistent. As mentioned above, by protecting the winding space within the enclosed container, the friction between the fibers and the air is minimized, which prevents the risk of disaggregation of the discontinuous winding when it is instantaneously untwisted.

[0062] The core yarn and the winding yarn can be monofilament yarns or multifilament yarns, independent of each other. For example, the core yarn can be a double filament yarn, where one filament is made of cashmere and the other of silk, while the winding yarn is made of linen. Or, in a similar but less expensive configuration, the core yarn can be a double filament yarn, where one filament is made of wool and the other of rayon, while the winding yarn is made of hemp. This makes it possible to obtain unusual combinations of properties such as thermal comfort, brightness, and feel in garments made from it. In particular, it allows for the currently unusual use of such materials as cashmere and wool to make summer garments, or garments that can be comfortably worn in hot and humid environments under any circumstances.

[0063] Specifically, the conveying steps include:

[0064] - The step of passing the core yarn and winding yarn through a longitudinal groove along the side surface of a cylindrical hollow body rotating at a predetermined speed, the longitudinal groove having an inlet and an outlet for the core yarn;

[0065] - The step of passing the core yarn and winding yarn through the spinneret orifice, the spinneret orifice facing the outlet of the longitudinal groove of the cylindrical hollow body and arranged at a predetermined distance from the outlet, and

[0066] The winding space is arranged between the outlet of the longitudinal groove of the cylindrical body and the spinneret hole, so that the container has an opening at the spinneret hole, and the core yarn and winding yarn pass through the spinneret hole to form a wound yarn.

[0067] More specifically, the pre-arrangement of the core includes the pre-arrangement of a first bobbin to receive the wound core yarn, while the pre-arrangement of the winding includes the coaxial mounting of a second bobbin or spool to receive the winding yarn into the cylindrical hollow body. The core conveying step includes pulling the core yarn out of the first bobbin with a predetermined tension and a predetermined unwinding speed equal to the conveying speed before conveying it into the central through-hole of the cylindrical hollow body. The conveying step also includes applying tension to the core at the exit of the spinneret, while the winding is being wound, and collecting the wound yarn on a third collecting bobbin.

[0068] This method can be performed using conventional hollow-shaft machines such as Hamel-type machines. If discontinuous winding is used, the machine will preferably be equipped with a protected winding space enclosed in a container.

[0069] According to a second aspect of the invention, an alternative method for manufacturing elastic fabrics includes the following steps:

[0070] - To form a wound yarn, the following steps are included:

[0071] -Pre-arranged with a first linear mass density Nm c The core yarn;

[0072] -Pre-arranged with a second linear mass density Nm set between 1 and 120 km / kg w yarn

[0073] - Apply a predetermined tension to the core yarn;

[0074] - The core yarn and winding yarn are conveyed toward the collection bobbin of the wound yarn at appropriate conveying speeds.

[0075] The conveying step allows the winding yarn to laterally reach the vicinity of the core yarn within the winding space;

[0076] - The winding yarn is wound around the core yarn in the winding space;

[0077] - Obtain the wound yarn on the collecting bobbin;

[0078] - Fabrics are formed from wound yarns by choosing a fabric manufacturing process between knitting and weaving processes;

[0079] The method includes a washing step selected between the step of washing the fabric and / or the step of washing the wound yarn.

[0080] in:

[0081] -The core yarn is a non-elastic yarn;

[0082] - Perform the winding step, so that

[0083] - The winding yarn forms a series of loops around the core yarn, the loops having a pitch longer than the diameter of the winding yarn, so that free space is left between the loops;

[0084] - In wound yarn, the core yarn and the winding yarn are twisted in opposite directions.

[0085] - The tension applied to the core yarn is lower than a predetermined force value (F1), and the minimum predetermined force value is selected such that the core yarn forms a series of ridges protruding between free spaces.

[0086] The washing process causes the wound yarn to shrink, compressing the ridge of the core yarn between the winding turns. This results in the wound yarn incorporated into the fabric becoming elastic, and consequently, the fabric itself becoming elastic.

[0087] The conveying speeds (v1, v2) are selected such that, during the winding step, each unit length of winding yarn is wound with a certain number of turns T.

[0088] - A number of turns T0 higher than the predetermined minimum number of turns of the yarn, and

[0089] - The number of turns T1 is lower than the predetermined maximum number of turns in the winding.

[0090] The minimum number of turns T0 and the maximum number of turns T1 depend on the second linear mass density Nm w ,

[0091] Among them, the second linear mass density Nm indicated in the corresponding row of the table below w Each value

[0092] <![CDATA[Nm w ]]> <![CDATA[T0]]> <![CDATA[T1]]> 1 20 50 2 40 500 3 60 600 10 150 1000 20 200 1300 30 250 1400 40 300 1500 50 300 1600 70 400 1700 90 500 1800 120 600 2000 ,

[0093] The minimum number of turns T0 and the maximum number of turns T1 are the numbers written into the corresponding rows of the table and the columns starting with T0 and T1, respectively.

[0094] The technical effects common to the methods according to the first aspect of the invention also apply in this case. The aforementioned optional features may also be optionally combined with features according to the methods according to the second aspect, thereby producing similar technical effects and advantages.

[0095] According to a third aspect of the invention, the elastic yarn comprises:

[0096] -Having a first linear mass density Nm c The core yarn;

[0097] -Has a second linear mass density Nm set between 1 and 120 km / kg w The winding yarn;

[0098] in

[0099] -The core yarn is a non-elastic yarn;

[0100] - The winding yarn forms a series of loops around the core yarn, the loops having a pitch (p) longer than the diameter (d) of the winding yarn, so that free space is left between the loops;

[0101] - In wound yarn, the core yarn and the winding yarn are twisted in opposite directions.

[0102] - The number of turns (T) of the wound yarn per unit length formed by winding.

[0103] - A number of turns T0 higher than the predetermined minimum number of turns of the yarn, and

[0104] - The number of turns T1 is lower than the predetermined maximum number of turns of the winding.

[0105] The minimum and maximum number of turns depend on the second linear mass density Nm w ,

[0106] Among them, the second linear mass density Nm indicated in the corresponding row of the table below w Each value

[0107] <![CDATA[Nm w ]]> <![CDATA[T0]]> <![CDATA[T1]]> 1 20 50 2 40 500 3 60 600 10 150 1000 20 200 1300 30 250 1400 40 300 1500 50 300 1600 70 400 1700 90 500 1800 120 600 2000 ,

[0108] The minimum number of turns T0 and the maximum number of turns T1 are the numbers written into the corresponding rows of the table and the columns that start with T0 and T1 respectively.

[0109] Advantageously, for the intermediate value between two adjacent values ​​of the second linear mass density Nmw indicated in the corresponding adjacent rows of the table, the minimum number of turns T0 and the maximum number of turns T1 are obtained by linear interpolation of the numbers written in the corresponding rows of the table and in the columns that begin with T0 and T1, respectively.

[0110] Advantageously, the core yarn and the winding yarn are obtained independently from fibers selected from natural fibers and man-made fibers, or combinations of natural fibers and man-made fibers.

[0111] Advantageously, the natural fibers are selected from flax; hemp; ramie; bamboo; jute; cotton; wool; silk; or combinations thereof.

[0112] Advantageously, the synthetic fibers are selected from the group consisting of: rayon, Tencel, Lyocell fiber, milk fiber, orange fiber, nettle fiber, kapok fiber, and combinations thereof.

[0113] The core yarn and winding yarn can be selected independently from single-ply and multi-ply yarns.

[0114] Advantageously, the core yarn is a double strand of cashmere and silk, while the winding yarn is a double strand of linen.

[0115] Advantageously, the core yarn is a double strand of wool and viscose fiber, while the winding yarn is a double strand of hemp fiber.

[0116] Elastic fabrics made at least in part from the aforementioned elastic yarns also fall within the scope of this invention. Attached Figure Description

[0117] The method for manufacturing elastic fabrics is described below with reference to the accompanying drawings, wherein

[0118] - Figure 1A and Figure 1B The steps of winding the core yarn around the winding yarn to obtain the wound yarn are illustrated schematically.

[0119] - Figure 2 A hollow spindle twisting machine is schematically shown for forming wound yarns during the manufacture of elastic fabrics;

[0120] - Figure 3 The diagram schematically shows a wound yarn in an extended state being collected on a collecting bobbin;

[0121] - Figure 4 This schematically illustrates the state of being in a non-extended position. Figure 4 yarn;

[0122] - Figure 5 It displays the first linear mass density Nm relative to the core yarn. c A graph showing the minimum and maximum tension applied to the core yarn;

[0123] - Figure 6 It displays the second linear mass density Nm relative to the winding. w Each unit length drawn

[0124] A diagram showing the minimum number of turns for a wound yarn.

[0125] Specific Implementation of Preferred Exemplary Schemes

[0126] refer to Figure 1A and Figure 1B To manufacture elastic fabrics, the method according to the invention includes passing a second linear mass density Nm w and the initial twisting direction "Z" ( Figure 1A ) or "S" Figure 1B The yarns 40 are wound onto a surface with a first linear mass density of Nm. c and the initial twisting direction "Z" ( Figure 1A ) or "S" Figure 1BThe step of making wound yarn around the core yarn 30 (that is, the same twisting direction as the winding yarn 40) is to produce wound yarn.

[0127] According to the present invention, and unlike yarns typically used to manufacture elastic yarns, the core yarn 30 is a non-elastic yarn, or in any case a substantially non-stretchable yarn, i.e., a yarn with a limiting elongation of 5% or less.

[0128] Typically, the initial twist direction of the winding yarn 40 is "Z", and the initial twist direction of the core yarn 30 is also "Z", as is commonly available on the market. Figure 1A ).

[0129] For the winding step, a predetermined tension F is applied to the core yarn 30, preferably as described in more detail below. Furthermore, the core yarn 30 and the winding yarn 40 are fed towards the winding space 35 at speeds v1 and v2 respectively, in which the winding yarn 40 reaches the core yarn 30 laterally, i.e., tangentially, forming a predetermined angle α between the axis of the core yarn 30 and the axis of the winding yarn 40. Angle α is chosen such that a series of turns 45 are formed around the core yarn 30, wherein the turns 45 are arranged relative to each other at a pitch p, wherein the pitch p is longer than the diameter d of the winding yarn 40, preferably a predetermined multiple of the diameter d. This multiple is preferably set to 1 to 8 times, more preferably 2 to 5 times. Therefore, free space 55 is left between the turns 45, the width of which depends on the pitch p and diameter d of the winding yarn 40.

[0130] The tension F applied to the core yarn 30 is selected such that the core yarn 30 is not overstretched, so that the core yarn 30 forms a series of ridges 31 due to the winding operation and during the winding operation, the ridges tend to protrude through the free space 55 between the turns 45 of the winding yarn 40 that have been wound around the core yarn 30.

[0131] Furthermore, by selecting conveyor speeds v1 and v2, the twisting direction of the winding yarn 40 changes during the winding step, from "Z" to "S" depending on the initial twisting direction of the winding yarn 40 in use. Figure 1A Or vice versa. Figure 1B ).

[0132] The method for manufacturing elastic fabrics also includes the step of forming a fabric from a wound yarn 50, which can be a substantially conventional process such as knitting or weaving.

[0133] A step for washing the yarn or fabric is also provided, in the latter case a flat-width washing step or a rope washing step, which is carried out during or before the step of dyeing the yarn or fabric. The washing step can be carried out on the wound yarn 50 and the fabric 60, the latter typically being the case for fabrics manufactured by a woven process.

[0134] Figure 3The diagram schematically illustrates the wound yarn 50 collected on a collecting bobbin (i.e., in one). In the wound yarn 50, the yarns 30, 40 (i.e., core yarn 30 and winding yarn 40) forming the structure of the wound yarn 50 are twisted in opposite twisting directions. Due to washing, the wound yarn 50 shrinks, as... Figure 4 As shown, the ridge 31 of the core yarn 30 is compressed between the turns 45 of the winding yarn 40, thus the wound yarn 50 is... Figure 3 The extended state A (where the same wound yarn 50 has a length L) A ) becomes Figure 4 The non-stretched state B (where the same wound yarn 50 has a ratio of L) A Short length L B Because the core yarn 30 and the winding yarn 40 are twisted in opposite directions, the shrinking wound yarn 50 has opposing internal reaction forces between the winding yarn 40 and the core yarn 30. This results in inherent elasticity, making the fabric containing the wound yarn 50 stretchable. Figure 3 And then release it. Figure 4 When the yarn 50 is washed, it undergoes elastic recovery. Therefore, the washing step performed on the yarn 50 and the fabric 60 produces or increases the elasticity of the yarn 50 incorporated into the fabric 60, and thus produces or increases the elasticity of the fabric 60.

[0135] This also applies to any elastic yarn according to the third aspect of the invention, wherein the core yarn 30 and the winding yarn 40 are twisted in opposite twisting directions in the wound yarn.

[0136] Apart from the limitation that the core yarn 30 does not contain any elastomer material, in contrast, in yarns used to manufacture conventional elastic fabrics, the core yarn 30 and the winding yarn 40 can contain any textile material independently of each other. However, the core yarn 30 and the winding yarn 40 can have the same composition.

[0137] In particular, the core yarn 30 and the winding yarn 40 may contain natural fibers such as hemp, ramie, bamboo, jute, cotton, wool, silk, or combinations thereof.

[0138] As an alternative, core yarn 30 and winding yarn 40 may contain synthetic fibers, such as rayon, Tencel, Lyocell, milk fiber, orange fiber, nettle fiber, kapok fiber, or combinations thereof.

[0139] The materials described above are preferred; however, synthetic fibers, such as nylon, polyester, acrylic, and other fibers, as well as combinations thereof, can also be used in this invention. Combinations of natural, man-made, and synthetic materials can also be used, preferably a combination of natural and man-made materials.

[0140] In one exemplary embodiment, the core yarn 30 and the winding yarn 40, regardless of their combination and their linear mass density Nm c Nm w Regardless, they are all yarns twisted in the same initial twisting direction "Z" or "S" and have the advantages mentioned above.

[0141] In some preferred exemplary embodiments, the core yarn 30 and the winding yarn 40 are selected independently of each other between monofilament yarns and multifilament yarns. In one example, the core yarn 30 is a double filament yarn, where one filament is made of cashmere and the other of silk, while the winding yarn 40 is made of linen. In another example, the core yarn 30 is a double filament yarn, where one filament is made of wool and the other of rayon, while the winding yarn 40 is made of hemp.

[0142] In this method, the tension applied to the core yarn 30 is preferably higher than a predetermined minimum force value F0, so that the core yarn 30 is stretched enough to easily wind the winding yarn 40 onto it, and to ensure the uniform characteristics of the wound yarn obtained by multiple winding units of the same winding machine.

[0143] Furthermore, according to the invention, the tension applied to the core yarn 30 is below a predetermined maximum force value F1 that should not be exceeded, so as not to lose the low friction and high heat and moisture transfer properties of the fabric, as well as the comfortable and cool feel provided to the wearer of clothing made of such fabric, and in order to obtain acceptable elastic properties of the wound yarn 50, as has been shown by experience.

[0144] The minimum and maximum tensile forces F0 and F1 depend on the first linear mass density Nm of the core yarn 40. c As shown in Tables 1 and 2. Figure 5 In the chart, the minimum tensile force F0 and the maximum tensile force F1 are relative to the first linear mass density Nm of the core yarn 40. c These are plotted as curves 71 and 72, respectively. Curves 71 and 72 were obtained by interpolating the values ​​from Tables 1 and 2, respectively.

[0145] According to the present invention, in this method, conveying speeds v1 and v2 are selected such that, in the winding step, the number of turns of the wound yarn 50 per unit length formed by winding the winding yarn 40 around the core yarn 30 is higher than a predetermined minimum number of turns T0, so that the stack of the turns is compact enough to produce elastic recovery when the tension acting on them is released, and to avoid uneven winding between the parallel winding units of the winding machine.

[0146] Furthermore, regardless of the above, the number of turns per unit length of the wound yarn 50 formed by winding the winding yarn 40 around the core yarn 30 is preferably lower than a predetermined maximum number of turns T1 that should not be exceeded, so as not to lose the low friction and high heat and moisture transfer properties of the fabric, as well as the comfortable and cool touch provided to the wearer of clothing made of such fabric, and in order to obtain acceptable elastic properties of the wound yarn 50, as experience has shown.

[0147] The minimum number of turns T0 and the maximum number of turns T1 depend on the second linear mass density Nm of the winding 40. w As shown in Tables 3 and 4. Figure 6 In the chart, the minimum number of turns T0 and the maximum number of turns T1 are relative to the second linear mass density Nm of the winding 40. w These are plotted as curves 81 and 82, respectively. Curves 81 and 82 were obtained by interpolating the values ​​in Tables 3 and 4, respectively.

[0148] like Figure 2 As shown, the steps of conveying the core yarn 30 and the core-spun yarn 40 are controlled by the speed at which the wound yarn 50 is collected on the collection bobbin 51 of the wound yarn 50, and thus, the core yarn 30 and the wound yarn 40 are pulled out from their respective bobbins (not shown and 41).

[0149] In one exemplary embodiment, the step of conveying the core yarn 30 toward the winding space 35 is performed via the central hole 63 of the first cylinder 61, which rotates at a predetermined high speed about its own axis 63'; that is, the core yarn 30 is conveyed along a substantially linear path. Conversely, the step of conveying the winding yarn 40 is performed along the outer surface 62 of the first cylinder 61, preferably along a yarn guide disposed thereon. Preferably, the first cylinder 61 is integrally and coaxially housed within a second hollow cylinder 64, the cylinders 61 and 64 forming the conveying unit 60. The bobbin 41 of the core-spun yarn 40 is fixed within the second cylinder 64, thus the core-spun yarn 40 is conveyed through the gap 65 between the bobbin 41 and the outer surface of the first cylinder 61.

[0150] In this exemplary embodiment, and particularly if the winding 40 is a discontinuous yarn, the winding space 35 is a generally enclosed space, i.e., a protected space, to limit the interaction of the material involved, particularly the winding 40, with the surrounding air. In this case, it remains as Figure 2As shown, the winding space 35 is defined between the outlet end 69 of the first cylinder 61 and the spinneret 66, preferably arranged on the axis 63'. The core 30 enters the winding space 35 at the outlet end, and the wound yarn 50 exits the winding space 35 through the spinneret and is conveyed toward the collecting bobbin 51. The winding space 35 is protected by a preferably axisymmetric wall 67 that converges from the inner surface of the second cylindrical hollow body 64 toward the spinneret 66, thereby forming a container that serves as the outlet channel for the wound yarn 50 from the winding space 35.

[0151] Figure 4 This shows the second linear mass density Nm for core-spun yarn 40. w For each value, a graph showing the predetermined minimum number of turns T0 that must be wound per unit length of elastic core yarn 50 is shown in curve 81. Curve 81 was obtained by interpolating the values ​​in Table 3.

[0152] Figure 6 The graph also shows curve 82, which indicates the second linear mass density Nm for core-spun yarn 40. w For each value, the predetermined maximum number of turns T1 of the elastic core-spun yarn 50 wound per unit length should not be exceeded in order to obtain acceptable elastic properties of the wound yarn 50, as has been shown empirically. Curve 82 was obtained by interpolating the values ​​in Table 4.

[0153] The foregoing description of exemplary embodiments of the invention has so fully revealed the invention from a conceptual standpoint that others will be able to modify and / or adapt these embodiments for various applications by applying present knowledge without further study and without departing from the invention, and therefore it should be understood that such modifications and alterations must be considered equivalent to the specific embodiments. Devices and materials used to achieve the different functions described herein may have different properties without departing from the scope of the invention. It should be understood that the wording or terminology used herein is for descriptive purposes and not for limitation.

Claims

1. A method for manufacturing an elasticized fabric, wherein the following steps are provided: - forming a wrapped yarn, comprising the following steps: - arranging a core yarn (30) having a first linear mass density Nm c previously - a pre-arrangement of a second yarn (40) having a second linear mass density Nm set between 1 and 120 km / kg, wherein said second yarn (40) is twisted with an initial twist direction selected between "Z" and "S", w a pre-arrangement of a second yarn (40) having a second linear mass density Nm set between 1 and 120 km / kg, wherein said second yarn (40) is twisted with an initial twist direction selected between "Z" and "S", wherein said core yarn (30) is twisted in an initial twisting direction identical to that of said winding yarn (40); - applying a predetermined tension force (F) to said core yarn (30); - feeding said core yarn (30) and said winding yarn (40) towards a collecting bobbin (51) of said wrapped yarn (50) at respective feeding speeds (vi, v2), wherein said feeding step is performed so that said winding yarn (40) reaches the proximity of said core yarn (30) laterally in a wrapping space (35); - wrapping said winding yarn (40) around said core yarn (30) in said wrapping space (35) so that, in said wrapping step, said winding yarn (40) is twisted in a final twisting direction opposite to said initial twisting direction, i.e. in a final twisting direction selected between "S" and "Z" respectively; - obtaining said wrapped yarn (50) on said collecting bobbin (51); - forming a fabric from said wrapped yarn (50) by means of a fabric making process selected between a knitting process and a weaving process; wherein said method comprises a washing step selected between a step of washing said fabric and / or a step of washing said wrapped yarn, characterized in that - said core yarn (30) is a non-elastic yarn; - said wrapping step is performed so that said winding yarn (40) forms a series of turns (45) around said core yarn (30) having a pitch (p) longer than the diameter (d) of said winding yarn (40) so that free spaces (55) are left between said turns (45); - said tension force (F) applied to said core yarn (30) is lower than a predetermined force value (Fi) selected so that said core yarn (30) forms a series of ridges (31) protruding between said free spaces (55), so that, by means of said washing step, said wrapped yarn (50) is shrunk so that said ridges (31) of said core yarn (30) are compressed between said turns (45) of said winding yarn (40), causing said wrapped yarn (50) incorporated in said fabric to become elastic and, consequently, also said fabric to become elastic, wherein said feeding speeds (vi, v2) are selected so that, in said wrapping step, a number of turns T per unit length of said wrapped yarn (50) is wrapped: - higher than a predetermined minimum number of turns To of said winding yarn (40), and - lower than a predetermined maximum number of turns Ti of said winding yarn (40), The minimum number of turns T0 and the maximum number of turns T1 depend on the second linear mass density Nm w , wherein, for each value of Nm w indicated in the corresponding row of the table below said minimum number of turns To and said maximum number of turns Ti being the numbers written in said respective rows and columns of said table starting with To and Ti respectively, wherein said second linear mass density Nm indicated in respective adjacent rows of said table w there is an intermediate value between two adjacent values of Nm.

2. The method according to claim 1, wherein said tension force applied to said core yarn (30) is set between a predetermined minimum force value Fo and a predetermined maximum force value Fi, The minimum force value and the maximum force value depend on the first linear mass density Nm of the core yarn c , wherein said first linear mass density Nm c is set between 1 and 120 km / kg, wherein for each first linear mass density value Nm indicated in the corresponding row of the table below c ， said minimum force value Fo and maximum force value Fi being force values in grams written in said respective rows and columns of said table starting with Fo and Fi respectively, wherein said first linear mass density Nm indicated in the respective adjacent rows of said table c there is an intermediate value between two adjacent values of Nm.

3. The method of claim 2, wherein, For the first linear mass density Nm indicated in the corresponding adjacent row of the table c The intermediate value between two adjacent values, the minimum force value F0 and the maximum force value F1, are obtained by linear interpolation of the force values ​​in the corresponding rows and columns starting with F0 and F1, respectively, written into the table.

4. The method of claim 1, wherein for the intermediate value between two adjacent values of the second linear mass density Nm w indicated in respective adjacent rows of the table, the minimum number of turns To and the maximum number of turns Ti are obtained by linear interpolation of the numbers written in respective rows and columns respectively headed by To and Ti of the table.

5. The method according to claim 1, wherein said washing step comprises the step of washing the fabric in water, either in flat form or in rope form.

6. The method according to claim 5, wherein said washing step is carried out under conditions and for a washing time such that the fabric shrinks from 15% to 30%.

7. The method according to claim 1, wherein said core yarn (30) and said winding yarn (40) are made independently from each other of a fiber selected between a natural fiber and a man-made fiber, or of a combination of a natural fiber and a man-made fiber.

8. The method according to claim 7, wherein said natural fiber is selected from the group consisting of: flax; hemp; ramie; bamboo; jute; cotton; wool; silk fibers; combinations thereof.

9. The method according to claim 7, wherein said man-made fiber is selected from the group consisting of: rayon, tencel, lyocell, milk fiber, orange fiber, nettle fiber, kapok fiber; combinations thereof.

10. The method according to claim 1, wherein said winding yarn (40) is a discontinuous yarn and said winding space (35) is a protected space enclosed in a container (67).

11. The method according to claim 1, wherein said core yarn (30) and said winding yarn (40) are selected independently from each other between a single filament yarn and a multi-filament yarn.

12. The method according to claim 1, wherein said core yarn (30) is a double filament yarn of cashmere and silk, respectively, and said winding yarn (40) is a double filament yarn of flax.

13. The method according to claim 1, wherein said core yarn (30) is a double filament yarn of wool and rayon, respectively, and said winding yarn (40) is a double filament yarn of hemp.

14. The method according to claim 10, wherein said feeding step comprises: - a step of passing said core yarn (30) and said winding yarn (40) along a lateral surface (62) of a cylindrical hollow body (61) rotating at a predetermined speed, said lateral surface (62) having a longitudinal groove (63) with an inlet (68) and an outlet (69) for said core yarn (30); - a step of passing said core yarn (30) and said winding yarn (40) through a spinneret (66), said spinneret facing said outlet (69) of said longitudinal groove (63) of said cylindrical hollow body (61) and being arranged at a predetermined distance from said outlet (69), and wherein said winding space (35) is arranged between said outlet (69) and said spinneret (66) so that said container (67) has an opening at said spinneret (66) and so that said core yarn (30) and said winding yarn (40) pass through said spinneret in the form of said wrapped yarn (50).

15. A method for manufacturing an elasticized fabric, wherein the following steps are provided: - forming a wrapped yarn (50), comprising the steps of: - arranging a core yarn (30) having a first linear mass density Nm c previously - prearranging a second yarn (40) having a second linear mass density Nm set between 1 and 120 km / kg; w of the yarn (40); - applying a predetermined tension (F) to said core yarn (30); - feeding said core yarn (30) and said winding yarn (40) towards a collecting tube (51) of said wrapped yarn (50) at respective feeding speeds (vi, v2), wherein said delivering step is carried out so that said winding (40) reaches the proximity of said core yarn (30) laterally in the winding space (35); - winding said winding yarn (40) around said core yarn (30) in said winding space (35); - obtaining said wound yarn (50) on said collecting tube (51); - forming a fabric from said wound yarn (50) by means of a fabric manufacturing process selected between a knitting process and a weaving process; wherein said method comprises a washing step selected between a step of washing said fabric and / or a step of washing said wound yarn, characterized in that - said core yarn (30) is a non-elastic yarn; - said winding step is carried out so that - said winding yarn (40) forms a series of turns (45) around said core yarn (30), said turns having a pitch (p) longer than the diameter (d) of said winding yarn (40) so that free spaces (55) are left between said turns (45); - in said wound yarn (50), said core yarn (30) and said winding yarn (40) are twisted with respective twisting directions opposite to each other; - said tension force (F) applied to said core yarn (30) is lower than a predetermined force value (Fl), said predetermined force value being selected so that said core yarn (30) forms a series of ridges (31) protruding between said free spaces (55), so that, by means of said washing step, said wound yarn (50) is shrunk so that said ridges (31) of said core yarn (30) are compressed between said turns (45) of said winding yarn (40), causing said wound yarn (50) incorporated in said fabric to become elastic and, consequently, also said fabric, wherein said delivering speed (vl, v2) is selected so that, in said winding step, a number of turns T per unit length of said wound yarn (50) is wound: - higher than a predetermined minimum number of turns TO of said winding yarn (40), and - lower than a predetermined maximum number of turns Tl of said winding yarn (40), The minimum number of turns T0 and the maximum number of turns T1 depend on the second linear mass density Nm w , wherein, for each value of Nm w indicated in the corresponding row of the table below ， said minimum and maximum numbers of turns TO and Tl being the numbers written in said table in said respective rows and columns headed by TO and Tl, respectively, wherein said second linear mass density Nm indicated in respective adjacent rows of said table w there is an intermediate value between two adjacent values of Nm.

16. An elasticized wound yarn (50), comprising: - a core yarn (30) having a first linear mass density Nm c of 20 dtex. - having a second linear mass density Nm set between 1 and 120 km / kg w of the wound package (40); wherein - said core yarn (30) is a non-elastic yarn; - said winding yarn (40) forms a series of turns (45) around said core yarn (30), said turns having a pitch (p) longer than the diameter (d) of said winding yarn (40), so that free spaces (55) are left between said turns (45); - in said elasticized wound yarn (50), said core yarn (30) and said winding yarn (40) are twisted with respective twisting directions opposite to each other; - said winding yarn (40) forms a number of turns T per unit length of said elasticized wound yarn (50), said number of turns T: - higher than a predetermined minimum number of turns TO of said winding yarn (40), and - lower than a predetermined maximum number of turns Tl of said winding yarn (40), The minimum and maximum number of turns depends on the second linear mass density Nm w , wherein, for each value of Nm w indicated in the corresponding row of the table below ， said minimum number of turns T0 and maximum number of turns T1 are the numbers in the respective row of said table and the column starting with T0 and T1, respectively, wherein said second linear mass density Nm indicated in respective adjacent rows of said table w there is an intermediate value between two adjacent values of Nm.

17. The elasticized wraparound yarn (50) of claim 16, wherein for an intermediate value between two adjacent values of the second linear mass density Nm w indicated in respective adjacent rows of the table, the minimum number of turns To and the maximum number of turns Ti are obtained by linear interpolation of the numbers written in respective rows and in columns headed by To and Ti, respectively.

18. The elasticized wrap yarn (50) according to claim 16, wherein said core yarn (30) and said ground yarn (40) are independently obtained from fibers selected from the group consisting of natural fibers and man-made fibers, or a combination of natural fibers and man-made fibers.

19. The elasticized wrap yarn (50) according to claim 18, wherein said natural fibers are selected from the group consisting of flax; hemp; ramie; bamboo; jute; cotton; wool; silk; and combinations thereof.

20. The elasticized wrap yarn (50) according to claim 18, wherein said man-made fibers are selected from the group consisting of rayon, Tencel, Lyocell, Milk Fiber, Orange Fiber, Nettle Fiber, Kapok Fiber, and combinations thereof.

21. The elasticized wrap yarn (50) according to claim 16, wherein said core yarn (30) is a double thread of cashmere and silk, respectively, and said ground yarn (40) is a double thread of flax.

22. The elasticized wrap yarn (50) according to claim 16, wherein said core yarn (30) is a double thread of wool and viscose, respectively, and said ground yarn (40) is a double thread of hemp.

23. An elasticized fabric comprising the elasticized wrap yarn (50) according to any one of claims 16 to 22.

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