EP3540105A1

EP3540105A1 - An elastic core sheat composite yarn, a yarn production method and a fabric produced by this yarn

Info

Publication number: EP3540105A1
Application number: EP18186110.5A
Authority: EP
Inventors: Omer Ozturk
Original assignee: Bossa Ticaret Ve Sanayi Isletmeleri Turk AS
Current assignee: Bossa Ticaret Ve Sanayi Isletmeleri Turk AS
Priority date: 2018-03-16
Filing date: 2018-07-27
Publication date: 2019-09-18

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

The present invention relates to composite yarns, yarn production methods and fabrics produced by such yarns, particularly denim fabrics.

PRIOR ART

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.
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.
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.
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.
As a result, because of all of the abovementioned problems, an improvement is required in the related technical field.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a 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.
An object of the invention is to provide a composite yarn with improved tensile strength.
Another object of the invention is to provide a fabric with improved elasticity and elastic recovery.
Another object of the invention is to provide a composite yarn in which the non-elastic filament properties contribute to the yarn.
Another object of the invention is to achieve manufacturing a composite yarn with improved tensile strength.

BRIEF DESCRIPTION OF THE FIGURES

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

10 Composite yarn
- 111 Core filament
- 112 Fibrous Sheath
- 12 Outer filament
20 Spinning 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

In this detailed description, several preferred embodiments of the invented composite yarn (10) are disclosed without forming any limiting effect in the scope of protection defined in the claims enclosed.
The composite yarn (10) of which the general appearance is given in Figure 1 comprises a fibrous sheath (112) consisting essentially of spun staple cotton fibres, a core filament (111) extending along the centre of said fibrous sheath (112), and an outer filament wrapped around the fibrous sheath (112). The core filament (111) and the outer filament (12) have different elongation and/or elastic recovery characteristics.
In a preferred embodiment of 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 preferably 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.
Since the fibrous sheath (112) comprises spun staple fibres like cotton, viscose, polyester, tencel, modal, etc. and preferably cotton is used. 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 cord sheath 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.
In this preferred embodiment of the invention, said outer filament (12) has a lower elasticity than the core filament. Accordingly, the outer filament (12) is selected from continuous filament polyamide, polyester, polyolefin, and preferably 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.
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.
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.
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.
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.
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. $Twisting (TPI) = alpha * square root (Ne) .$
In the composite yarn (10), alpha (twisting coefficient) will be between 3.5 and 5.5 and preferably between 3.8 and 4.5.
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) can be 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.
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.
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".

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	444	8.7	10	7.6	31	3888
New method	495	10.8	9.3	6	38	4283
% Increase- Decrease	11%	24%	-7%	-21%	-22.60%	10%

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.
In an alternative embodiment of the subject matter composite yarn (10), the core filament (111) may have a lower elasticity than the elasticity of the outer filament (12). Accordingly, in practice, the core filament (111) can be selected from a non-elastic filament and the outer filament (12) can be selected from an elastic filament, and the composite yarn (10) can thus be formed by the above-mentioned production method.
In another alternative embodiment of the invention, both the core filament (111) and the outer filament (12) can be wrapped around the fibrous sheath (112). Thus, since there is no gap at the centre of the fibrous sheath (112), the tensile strength is much more improved.
The protection scope of the present invention is set forth in the annexed claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.

Claims

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).
An elastic composite yarn (10) according to claim 1, wherein said outer filament (12) is wrapped around the fibrous sheath (112) in a manner that it does contact the core filament (111) along the length of the elastic composite yarn (10).
An elastic composite yarn (10) according to claim 1, wherein said fibrous sheath (112) surrounds the core filament (111) without any room therebetween.
An elastic composite yarn (10) according to claim 1, wherein the elasticity of the core filament (111) is greater than that of the outer filament (12).
An elastic composite yarn (10) according to claim 1 or 4, wherein the growth rate of the core filament (111) is lower than that of the outer filament (12).
An elastic composite yarn (10) according to claim 1, wherein said core filament (111) comprises elastane.
An elastic composite yarn (10) according to claim 1, wherein the fibrous sheath (112) comprises spun staple fibre like cotton, viscose, polyester, tencel, modal, preferably comprises cotton fibre.
An elastic composite yarn (10) according to claim 1, wherein the outer filament (12) comprises at least one of continuous filament polyester, PTT, polyamide, PBT, preferably comprises PBT fibre.
An elastic composite yarn (10) according to claim 1, wherein the drafting ratio of the core filament (111) is between 2.0 and 6.0 and preferably between 3.0 and 4.0.
An elastic composite yarn (10) according to claim 1, wherein the drafting ratio of the outer filament (12) is between 1.0 and 1.5 and preferably between 1.0 and 1.15.
An elastic composite yarn (10) according to claim 1, wherein the yarn count of said core filament (111) is between 10 and 140 denier and preferably between 40 and 80 denier.
An elastic composite yarn (10) according to claim 1, wherein the count of the cord related to said fibrous sheath (112) is between Ne 0.30 and 2.0 and preferably between Ne 0.5 and 1.0 according to English counting system.
An elastic composite yarn (10) according to claim 1, wherein the composite yarn (10) count is between Ne 5/1 and Ne 30/1 according to English counting system.
An elastic composite yarn (10) according to claim 1, wherein the yarn count of said outer filament (12) is between 30 and 140 denier and preferably between 40 and 80 denier.
An elastic composite yarn (10) according to claim 1, wherein the twisting coefficient of the composite yarn (10) is between 3.5 and 5.5 and preferably between 3.8 and 4.5.
A fabric, preferably a denim fabric comprising an elastic composite yarn (10) according to any of the preceding claims as the weft yarn and/or warp yarn.
A method for manufacturing elastic composite yarn (10), characterized by comprising steps of:
- feeding a core filament (111) to the spinning unit (25),

- feeding a fibrous sheath (112) to the spinning unit (25) in a manner surrounding the core filament (111),

- including the core filament (111) to the spinning triangle such that the core filament (111) is provided at the center of the fibrous sheath (112),

- feeding an outer filament (12) to the spinning unit (25),

- including the outer filament (12) in the yarn structure in a manner wrapping the fibrous sheath (112),

- twisting the fibrous sheath (112) and the outer filament (12) together.
An elastic composite yarn (10) production method according to claim 17, wherein said core filament (111) and outer filament (12) are fed through a joining drum (251).
An elastic composite yarn (10) production method according to claim 17, wherein the distance (x) between the core filament (111) and the outer filament (12) at said joining drum (251) is between 0.1 and 30 mm and preferably between 1 and 20 mm.
An elastic composite yarn (10) production method according to claim 17, wherein the core filament (111) is guided in a groove (252) and the outer filament (12) is guided in another groove (252) at said joining drum (251).
An elastic composite yarn (10) production method according to claim 17, wherein prior to being fed to the spinning unit (25), the core filament (111), the fibrous sheath (112) and the outer filament (12) are passed through drafting rollers (24) which are independent from each other.