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26 August 2011

Explanation of different types of yarn


1. Single yarn
Single yarn is the simplest continuous strand of textile mtl composed of one of the following : -

(i) Continuous filament
Filament consists of very long, thin cylinder type fibre twisted together. Continuous filament yarns are the simplest in the structure but can be subjected to many modifying process for changing their texture, extensibility, bulk and other properties. In the manufacture of man made filaments, a solution is forced through very fine holes of spinneret, at which point the solution solidifies by coagulation, evaporation or cooling.
Continuous filament yarns in fabric form usually have excellent strength & uniformity. This yarn can be made much finer in linear density and diameter than staple yarns. In an untextured form, continuous filament yarns are not posses a combination of good covering power tactile qualities, comfort and a pleasing appearance. Silk is a natural filament, synthetic filament yarn is used to produce silk like effect.

Filament yarns are two types:-
a) Monofilament: Which containing one filament. e.g. Silk.
b) Multifilament: Which contains two or more filaments e.g. Nylon.

(ii) Staple or spun yarn
Yarn in which number of discontinuous fibres are hold together generally by twist is called staple yarn. Generally staple yarn consists of short length fibre from 25mm to 180mm. To produce the yarn from such kind of short fibres, the fibres (carded or carded and combed) should keep parallel and then wound together by either clockwise or anti-clockwise twist. The yarn which is made in this way is also called spun yarn.
Staple yarns categorically have excellent tactile qualities (handle, good covering power & excellent comfort factor) and are aesthetically pleasing. However, staple yarns as a group are not as strong as uniform as continuous filament yarns of equal linear density. Finally, because staple fibres are processed as a mass rather than individually, the number of fibres per yarn cross-section varies considerably along the yarn length. This condition limits the fineness of spun yarn.

Spun yarns are two types:
a) Homogeneous: Which are spun from one type of fibre e.g. 100% cotton yarn.
b) Blended: Which are spun from more than one type of fibres e.g. cotton-polyester blend yarns.

(iii) Modified continuous filament
The continuous filament yarns which are textured or modified to change their appearance and other properties, are called modified continuous filament.

2. Multi folded or plied yarns
They are made by twisting together two or more single yarns. e.g. Sewing threads. The yarn which has been plied by plying process is called plied yarn. Plying process is done to make the yarn strong and balanced.

3. Cabled yarn
Cabled yarns are made by twisting together two or more multi folded yarns. e.g.  Cords.

4. Gimped yarn
Gimped yarn is a type of yarn where a yarn called core yarn is wrapped with another yarn or  filament. The yarn fed through at the delivery rollers only is called core. Here, the core yarn remains untwisted or intact, twist only given to the yarns that are wrapping it. Besides, the surrounding yarns can be unwrapped.

5. Complex yarn or core spun yarn:
In a complex yarn, either a continuous filament core is surrounded by staple fibre or a spun yarn or core is surrounded by continuous filaments. There is a basic difference between gimped yarn and core  spun yarn. In case of gimped yarn the core yarn is wrapped by another yarn but in core spun yarn, the core yarn is wrapped by fibre (not yarn).
Core spun yarns are two component structure with core and sheath. Generally, continuous filament yarn is used as core and the staple fibre are used sheath covering. The core spun yarn are used to enhance functional properties of the fibres such as strength, durability and stretch comfort. Polyester filaments are often wrapped with a cotton outer layer in order to provide the strength and resiliency of polyester, along with the moisture absorbent and dye of affinity of cotton.

6. Novelty or fancy yarn
Fancy or novelty yarns are of decorative purpose. They are made by introducing spiral forms of irregularity or hairiness into either spun continuous filament yarn. e.g. chenille yarn, loop yarn, slub yarn, snarl yarn. Novelty yarns are usually uneven is size, varied in color or modified appearance by their formation. Tin single yarns, the irregularities may be caused by inclusion of knots loops, slub etc. In plied yarns, the irregularities may be affected by variable delivery of one or more spun yarn components or by twisting together dissimilar single yarns.

7. Strength yarn
Yarn that have been programmed for extra ordinary extensibility are known as strength yarn. Most stretch yarn can be extended from one of one half twice their normal or relaxed length. The structures are not only highly extensible but highly elastic as well.

8. High bulk yarn or texturized yarn
In texurized yarn the filament have been crimped regular pattern. It is also called bulk yarn. A high bulk yarn is a staple or continuous filament yarn, that has normal extensibility but unusually high degree of loftiness or fullness. These yarns retain their bulkiness under both relaxed and stressed conditions. Great covering power with little weight is possible in fabrics composed of high bulk yarn..

9. Metallized yarn
Metllized yarns may be formed a metal wire combined with textile, a gimped yarn combined with metal or a core metal/plastic wrapped with metal dust by the help of glue.

10. Combed yarn
Combed yarn is better in quality than carded yarn. According to the technical parameter the long length fibre is considered as better. Because long fibre decrease hairiness in yarn, give strength to the yarn and yarn become more even. To obtain the long length fibre in yarn, the short fibres should be removed. For this purpose a processing is done called Combing. So, the yarn which is obtained by combing action is called combed yarn. In case of combed yarn short fibre percent is low and yarn is regular. Hence,  after weaving or knitting the fabric looks very even. As a result the price will be more.

11. Carded yarn
Carded yarn is interior in quality as combing action is not done here. Therefore, the strength of the carded yarn is lower than combed yarn and in carded yarn the percentage of short fibre is high, that is why yarn will have more hairiness. Hence, the fabric manufactured from carded yarn will be uneven.

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