An elastic core sheath composite yarn production method

Abstract

The invention relates to an elastic composite yarn (10), characterized by comprising a core filament (111), a fibrous sheath (112) surrounding said core filament (111) and an outer filament (12) wrapped around said fibrous sheath (112) and having different elasticity and / or growth rate than said core filament (111).

Description

TECHNICAL FIELD

[0001] The present invention relates to a yarn production method.PRIOR ART

[0002] Composite yarns can be basically defined as yarn structures which have different physical and chemical characteristics when compared with the components thereof and obtained by joining at least two yarn and / or fibre groups, which are different from each other, by means of different methods. Composite yarns can be obtained by means of using pluralities of different production methods like spinning, folding, twisting, etc. in a stand-alone manner or together. Composite yarns are generally designed and used for developing and improving yarn characteristics. In this direction, it is possible meet pluralities of different composite yarn types developed depending on the usage area and fabrics obtained by using these yarns.

[0003] One of the textile sectors where composite yarns are frequently used is the ready wear sector. The most important advantages presented by the ready wear sector to the users in the daily life are the wearing comfort, usability, high tensile strength and improved elasticity. While the requests of the users for these characteristics increase, the sector widens its studies in this area.

[0004] Particularly in obtaining fabrics with higher tensile strength and elasticity and lower growth, composite yarns which have core yarn in the structure thereof are preferred. Said composite yarns are mostly produced by means of ring spinning systems. At the center of these yarn structures, there is an elastic filament and there is a non-elastic filament extruded separately and brought together at a joining drum. The periphery of the elastic filament and non-elastic filament is covered by a fibrous sheath (hereafter it will be called fibrous sheath) formed by spun staple cotton fibre. In this application and in similar applications, in yarns and in fabrics obtained from yarn, elasticity and elastic recovery behavior develop. For instance, CH373291 or EP2006422 discloses such solutions which may be regarded as an example to such yarns.

[0005] However, the elastic and inelastic filament yarns which form the composite structure in the yarn and provided at the center of the yarn lead to decrease of the tensile strength values. Since the increase of the tensile strength is realized by means of obtaining a compact structure by wrapping completely around itself during encircling the fibrous sheath. In other words, the fibrous sheath always tends to advance towards the center and thus tends to be twisted. However, in said yarn embodiments, the elastic filament and the non-elastic filament which form the core part of the yarn have rooms at the center of the fibrous sheath. These rooms reduce the contact surface of the fibrous sheath and prevent sufficient wrapping thereof and lead to insufficient tensile strength. Since the yarn tensile strength is insufficient, tear and breakage occur in the fabrics obtained from this yarn and undesired conditions occur.

[0006] JPS5711233 generally discloses a yarn comprising a high stretch elastic yarn as a core yarn; a spun yarn covering the periphery of core yarn and a low stretch processed yarn spinning with the core yarn covered by spun yarn.

[0007] JPH03185138 discloses a yarn comprising a cotton fiber fleece (F); an elastic fiber filament (E) and a synthetic fiber filament (N). They are fed to a front roller in a fine spinning machine in a manner that the yarn E is superposed on center of the fleece F and the yarn N is separated from the fleece F and the yarn E to side direction. Next, yarn N is twisted with the fleece F having yarn E on its centre.

[0008] JP2004036016 generally discloses a composite elastic yarn obtained by winding a fiber bundle comprising only filaments around the outer periphery of a fiber bundle comprising an elastic fiber as a core and staple fibers as a sheath in a twist coefficient of 2.6 to 7.2.

[0009] JP2010209487 discloses a composite yarn obtained by coating of the core composed by elastic fiber by a sheath composed by short fibers and synthetic fiber multifilaments. The sheath layer is obtained by uniformly mixing the short fibers with the synthetic fiber multifilaments or mixing the short fibers with the synthetic fiber multifilaments in groups.

[0010] JP3161115 discloses a composite yarn capable of preventing sweat and discomfort. The composite yarn comprises a core portion made of an elastic yarn, a sheath portion covering the core portion and made of a hydrophobic fiber, and a presser yarn wound around the sheath portion.

[0011] JPH0278583 discloses a synthetic maple filament yarn composed of a rubber filament-like elastic filament yarn, a yarn layer containing a fiber-based rope, and a core layer comprising a core yarn.

[0012] JPH09279430 discloses a composite yarn obtained by covering the polyurethane elastic filament or a covered filament obtained by winding with the elastic filament as the core filament with nylon-woolie yarn, with staple fiber to give the enveloping layer, then winding the outer periphery with long fiber such as nylon or polyester, etc., rich in durability.

[0013] As a result, because of all of the abovementioned problems, an improvement is required in the related technical field.BRIEF DESCRIPTION OF THE INVENTION

[0014] The present invention relates to a method for production of composite yarn and a fabric produced by this yarn, preferably a denim fabric, for eliminating the above mentioned disadvantages and for bringing new advantages to the related technical field.

[0015] An object of the invention is to achieve manufacturing a composite yarn with improved tensile strength.

[0016] 1 Denier corresponds to 0,11 Tex.

[0017] 1 Ne corresponds to 590 Tex.BRIEF DESCRIPTION OF THE FIGURES

[0018] Figure 1 is the general view of the composite yarn. Figure 2 is the detailed view of the composite yarn. Figure 3 is the general view of the spinning system for composite yarn. Figure 4 is the detailed view of the spinning system. REFERENCE NUMBERS

[0019] 10Composite yarn 111 Core filament 112 Fibrous Sheath 12 Outer filament 20Spinning System 21 Outer filament roller 22 Core filament roller 23 Fibrous sheath roller 24 Drafting rollers 25 Spinning unit 251 Joining drum 252 Groove 253 Sleeve coated roller 26 Wrapping bobbin x:Distance between filaments DETAILED DESCRIPTION OF THE INVENTION

[0020] The composite yarn (10) produced with the method according to the invention and of which the general appearance is given in Figure 1 comprises a fibrous sheath (112) consisting of spun staple cotton fibres, a core filament (111) extending along the centre of said fibrous sheath (112), and an outer filament made of PBT wrapped around the fibrous sheath (112). The core filament (111) and the outer filament (12) have different elongation and / or elastic recovery characteristics.

[0021] According to the invention, said core filament (111) is selected from elastic filaments and accordingly from groups of elastomeric fibres. Elastomeric fibres are of a structure that exhibits good elastic recovery behaviour, with length of 200 to 600%, preferably 200 to 400% elongate before breakage and return to initial length when force is removed. Despite their high flexibility properties, they have low breaking strength values. For this reason, composite yarn is used in the structure to improve elasticity and elastic recovery behaviour of the structure. Elastane is used as the core filament (111) in the composite yarn (10) structure. Accordingly, in a preferred embodiment, the count of the core filament (111) in the elastane structure is between 10 and 140 denier, preferably between 40 and 80 denier.

[0022] The fibrous sheath is cotton. The spun staple cotton fibre used in the fibrous sheath (112) ensures high moisture absorbing. Due to this feature, it is widely used to enhance clothing comfort. The fibrous sheath (112) has low elasticity due to the extremely low fibre length of the spun staple fibres, and therefore the recovery behaviour after elastic extension is very weak. However, all of these are high tenacity fibres, and thus the composite yarn (10) is functioning to increase tensile strength within the structure. Accordingly, in a preferred embodiment, the yarn count of the fibrous sheath (112) is between Ne 0.30 and Ne 2.0, preferably between Ne 0.5 and 1.0, according to the English count system.

[0023] According to the invention, the outer filament (12) is PBT (Polybutylene-terephthalate). The outer filament (12) may preferably comprise a single or multiple continuous filaments. PBT fibres have good tensile strength values as well as high recovery behaviour. In addition, due to the resistance against wear, the use of the composite yarn (10) in the outermost layer can contribute to the development of wear resistance. Accordingly, in a preferred embodiment, the yarn count of the outer filament (12) in the non-elastic structure is between 30 and 140 denier, and preferably between 40 and 80 denier.

[0024] Ring spinning system (20), whereon specific modifications are made, is used in formation of the composite yarn (10) structure. Said spinning system (20) has been given in Figure 3 and it basically comprises an outer filament roller (21) which carries the outer filament (12), a core filament roller (22) which carries the core filament (111), a fibrous sheath roller (23) which carries the fibrous sheath (112), drafting rollers (24), spinning unit (25) and a wrapping bobbin (26). In the subject matter mechanism, a separate drafting rollers (24) are provided for each yarn component. Each of the materials output from the outer filament roller (21), the core filament roller (22) and the fibrous sheath roller (23) are firstly passed through the drafting rollers (24) related thereto and they are guided to the spinning unit (25). The drafting rollers (24) related to the core filament (111), which has elastic yarn structure, is configured such that the draft ratio is between 2 and 6 folds, preferably between 3 and 4 folds. The drafting rollers (24) related to the outer filament (12) which does not have elastic structure is configured such that the draft ratio is between 1 and 1.5 folds, preferably between 1 and 1.15 folds.

[0025] The joining drum (251) which is one of the elements provided in the spinning unit (25) has been revised for the production of composite yarn (10). Under said joining drum (251), there is sleeve coated cylinder (253) which provides alignment of the composite yarn (10) components. There are two grooves (252) on the joining drum (251). Double V-grooved joining drum (251) brings together the components which will form the composite yarn (10) which enters into the spinning unit (25) and they are wrapped in roller form by means of twisting at the output of the spinning unit (25). On the other hand, in this preferred embodiment of the present invention, a double V-grooved joining drum (251) is used.

[0026] In the formation of the composite yarn (10), the core filament (111) is fed to a groove (252) and the outer filament (12) is fed to another groove (252). The core filament (111) and the outer filament (12) do not contact each other at any point during production and inside the composite yarn (10) structure. The fibrous sheath (112) is fed to the spinning unit (25) in order to be joined to the core filament (111) from the level where the groove (252) where the core filament (111) is fed is provided. At the spinning triangle formed at the output of said sleeve coated roller (253), the core filament (111) contributes to the spinning process in a manner staying at the middle region of the fibrous sheath (112). Thus, the fibrous sheath (112) completely covers the core filament (111). The outer filament (12) is twist together with the fibrous sheath (112) and directly contributes to the composite yarn (10) structure.

[0027] A distance (x) is defined between the filaments between the point where the core filament (111) passes through the joining drum (251) and where the core filament (111) exits under the sleeve coated roller (253), in other words, where the core filament (111) is included to the spinning triangle and the point where the outer filament (12) is included to the spinning triangle. The value of the distance (x) between the filaments is between 0.1 and 30 mm and preferably between 1 mm and 20 mm.

[0028] The composite yarn (10) count can be between the final values of Ne 5 / 1 and 30 / 1, according to the English counting system. Yarn twisting is the twisting coefficient (alpha) which is principle for the twisting in yarn production. Twisting TPI = alpha * square root Ne

[0029] In the composite yarn (10), alpha (twisting coefficient) will be between 3.5 and 5.5 and preferably between 3.8 and 4.5.

[0030] As a result, at the structure of the subject matter composite yarn (10), a single component is located centrally within the fibrous sheath (112), thus less space is created. Accordingly, the fibrous sheath (112) is wrapped around the core filament (111) without any room therebetween and thus with increased contact surface. In addition, the outer filament (12) is wrapped around the fibrous sheath (112) so as not to contact the core filament (111). In this case, the fibrous sheath (112) is wrapped around the core filament (111) and the fibrous sheath (112) is wrapped by the outer filament (12) and, as a result, the tensile strength and the tensile strength values of the composite yarn (10) are improved. By means of this improvement provided in the tensile strength value of the composite yarn (10), the twisting coefficient is reduced and the composite yarn (10) can be produced at a lower twisting when compared with similar yarns. Additionally, since the core of the composite yarn (10) is formed by the core filament (111) and since the fibrous sheath (112) is wrapped by the outer filament (12), the fibrous sheath (112) can be selected to have more delimited physical characteristics when compared with the spun staple fibres used in similar yarn embodiments. Also, the presence of the outer filament (12) on the composite yarn (10) structure allows the composite yarn (10) and the fabric (10) to develop elasticity and elastic recovery behaviour and enhances wear resistance. As a result, the tensile strength values of the composite yarn (10) according to the invention increase by 8-12% and the elasticity values increase by 15-25% with respect to similar yarn embodiments.

[0031] In the light of the abovementioned information, the details and outputs of a test realized for the subject matter composite yarn (10) have been given below.

[0032] First of all, the information related to the test mechanism and test method is as follows: Yarn count measurement: 120 yards of the yarn exiting the ring machine is wrapped in zweigle L232 machine. The weight of this wrapped yarn is measured in Mettler PM460 weighing device. The yarn count is read as Ne from the Epson HX20 device connected to the weighing device. Yarn tensile strength and elasticity measurement: Five of the yarns, which exit the ring yarn machine, are fixed to the ustertensorapid3 device for providing consistent test results. The test speed is adjusted to 5 m / minute. Totally 50 tests are made such that ten each tests are made by using each sample. The other parameters are taken to automatic position. The yarn tensile strength is measured as grams and the elasticity is measured as %. M&S Growth rate measurement: It is determined by means of the method of "Marks & Spencer Extension, residual extension of stretch woven fabrics test". Levi's Growth rate measurement: It is determined by means of the method of "Strech properties of woven fabrics ASTM D3107 - Modified". Weft breaking strength measurement: It is determined by means of the method of "Breaking stregth - Grab Method tensile strength ASTM D5034 - Modified". Weft tearing resistance measurement: It is determined by means of the method of "Tearing resistance of textile fabrics ASTM D1424 - Modified".

[0033] Accordingly, the obtained test outputs are given in the table below. Method Yarn tensile strength [g] Yarn elasticity [%] M&S growth rate (%) Levi's growth rate Weft breaking strength [kg] Weft tearing resistance [g] Present method 4448.7107.6313888New method 49510.89.36384283% Increase-Decrease 11%24%-7%-21%-22.60%10%

[0034] With reference to the table above, it is desired that the yarn elasticity and tensile strength values are high. It is also desired that the fabric growth rate value is low. It is also desired that the fabric weft breaking strength and weft tearing resistance values are high. Thus, by means of this test, it has been proven that the present invention provides all advantages it offers. Accordingly, it is obvious that a fabric, produced by using the subject matter composite yarn (10) in the weft and / or warp, for instance a denim fabric will also have the same advantages.

Claims

1. An elastic composite yarn production method by ring spinning comprising the following steps: - passing a core filament (111), made of elastane and fed from a core filament roller (22), through first drafting rollers (24), said core filament (111) being passed through said first drafting rollers (24) with a drafting ratio of between 2 and 6, - passing a fibrous sheath (112), made of cotton staple fibers and fed from a fibrous sheath roller (23), through second drafting rollers (24), - passing an outer filament (12), made of Polybutylene-terephthalate and fed from an outer filament roller (21), through third drafting rollers (24) with a drafting ratio of between 1 and 1.5, - feeding the core filament (111) to a first groove of a joining drum (251) and the outer filament (12) to a second groove of said joining drum (251), - feeding the fibrous sheath (112) at the level of the first groove, - performing with a ring spinning unit, a twisting together of the outer filament (12) and the fibrous sheath (112) at an outlet of a sleeve coated roller (253), at the so call spinning triangle area, whereby the core filament (111) remains in the middle region of the fibrous sheath (112) so as to be wrapped around the core filament (111) and thereby covers it completely, - and collecting the obtained composite yarn (10) on a wrapping bobbin (26), - wherein the distance X between the core filament (111) and the outer filament (12) in said joining drum (251) has a value in the range of 0.1-30 mm.

2. An elastic composite yarn (10) production method according to claim 1, wherein the yarn count of the core filament (111) is in the range of between 10 and 140 denier (11,1 dTex and 155,5 dTex).

3. An elastic composite yarn (10) production method according to claim 1, wherein the yarn count of the fibrous sheath (112) is between 0.3 and 2 Ne (1966 Tex and 295 Tex).

4. An elastic composite yarn (10) production method according to claim 1, wherein the yarn count of the outer filament (12) is in the range of between 30 and 140 denier (33,3 dTex and 155,5 dTex).

5. An elastic composite yarn (10) production method according to claim 1, wherein the twisting is carried out so that the twist coefficient alpha of the composite yarn (10) obtained is in the range of between 3.5 and 5.5, wherein the twisting in twists per inch (TPI) = alpha * square root of the yarn count in Ne.

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