From the variety of yarns that
are made commercially, it would appear that there is no limit to the number of
functional and aesthetic design possibilities and to the number of distinctly
different yarns. Natural, regenerated, and synthetic fibers are processed alone
and in multitude of blend combinations on staple yarn systems. Several
combinations of continuous filament and staple fiber yarn blends are also made.
Even when a yarn is made from a particular staple fiber or continuous filament,
a great number of variations are possible. Through subsequent processing of a
chemical or mechanical nature, basic staple or continuous filament yarns can
acquire substantially different structural features that can be dramatically
change the appearance and functional performance of the original yarns.
Yarns can be classified as follows
Notwithstanding the seemingly
infinite variety, yarns may also be conveniently classified according to their
physical properties and performance characteristics. The physical properties
and performance characteristic of yarns depend on the physical properties of
the constituent fibers or filaments and on yarn structure.
PARAMETERS AFFECTING THE PHYSICAL PROPERTIES OF YARN:
Physical properties of yarn also
depend on the various parameters, such as:-
i) Higher the staple length higher the strength.
ii)
Lower the staple length lowers the strength.
iii) Higher the uniformity of fiber length stronger the
yarn.
iv)
Higher the maturity ratio higher the strength.
v)
Finer fiber will produce strong yarn.
vi)
Strength increases with twist up to an optimum limit.
vii)
Lower the twist lowers the strength but there is a
minimum twist limit.
viii) Higher the unevenness of yarn lowers the strength.
ix) The strength of cotton fiber increases with higher
moisture content, but for wool strength decreases for higher moisture content.
x)
For synthetic fiber moisture does not have significant
impact on strength.
xi)
Some finishes, like mercerization increases yarn
strength.
xii)
Higher number of drawing passage weaker the yarn.
xiii) Higher major number of beating point weaker the
strength .Closer nip distance will produce more short fibers thus weaker the
yarn.
Yarn Type
|
General Yarn Properties
|
Staple yarns
Combed cotton
Carded cotton
Worsted
Woolen
|
Excellent hand,
covering power, comfort and textured appearance Fair strength and uniformity
|
Continuous filament yarns
Natural
Man-made or synthetic
|
Excellent
strength, uniformity and possibility for fineness Fair hand proof covering
power
|
Novelty yarn
Fancy
Metallic
|
Excellent
decorative features or characteristics
|
Special end-use or industrial yarns
Tire cord
Rubber or elastic
Core
Multiply
Coated
|
Purely
functional; designed to satisfy a specify a specific set of condition.
|
High bulk yarns
Staple
Continuous filament (Taslan)
|
Great covering
power with little weight, good loftiness or fullness
|
Stretch yarn
Twist-heat set-untwist
(Helanca, Fluflon)
Crimp-heat set
(Ban-lon)
Stress under tension
(Agilon)
Knit-deknit
Gear crimp
|
Stretch ability
and cling without great pressure, good hand covering power
|
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