The
word blending conveys two different aspects of spinning. In one sense it means
through mixing of two or more varieties of a fibre to achieve uniformity in
fibre properties thus consistency in yarn quality. This is mainly done in
natural fibres because these have large numbers of variability. Actually the
blending means mixing two or more fibres together, say polyester and cotton.
The blending is mainly done to obtain the homogeneity in the fibre properties
which is essential for consistency in yarn quality.
Objectives of Blending
The objective of blending of two or more fibres include functional and
aesthetics properties of yarns and fabrics, process performance, economy and
incorporation of fancy effects.
1. Improvement in
functional properties:
One of the main objectives of blending dissimilar
fibres is to improve the functional properties of fabrics so as to get desired
results in terms of wear comfort and service life. Take the example of
polyester –viscose blend. a 100% Polyester fabric is not suitable because of
hydrophobicity, pilling, static charge accumulation, hole melting, poor soil
resistance and wash ability but blending with viscose overcome such problems
and due to moisture regain of viscose it also impart wear comfort to
polyester-viscose blend. On the other hand 100% viscose having low tear and
tensile strength, poor crease and abrasion resistance but addition of polyester
overcome such difficulties and impart excellent dimensional stability, crease
resistance, quick drying and high tensile & tear strength. Thus blending
offers a means to suppress the negative and bring out positive attributes. But
the positive and negative attributes are end use specific.
2. Improved Process
performance:
Blending also improves the performance of
different processes. Natural fibres are non-homogeneous in their properties but
blending with man-made fibres overcomes the deficiencies of natural fibres. eg
the blending of longer and finer manmade fibres with cotton can be used to spin
finer yarns, reduce end breakages and increase spindle speed of ringframe. Also
this blend require a lower twist than 100% cotton, it would lead to increase in
productivity. Improvement in process performance not always achieved by
addition of manmade fibres only. Addition of natural fibres can also improve
process performance. Spinning of rotor yarn from 100% polyester fibre is
troublesome at some time but addition of cotton facilitates spinning as cotton
fibres act as carriers. Also addition of cotton viscose in polyester help in
trouble free carding.
3. Economy:
The
blending of natural and manmade fibres gives the stability to the price. Actually
the price of natural fibres depends on uncontrolled factors like climate etc.
so their price remains variable within a year and from year to year. This
creates instability in the financial conditions of the mills. Price stability
is necessary for mills to pursue optimum fibre purchase. Also now days the
natural fibres become costlier than manmade fibres. Depending on price pattern
the spinner always use cheap fibre for blending to produce desired quality yarn
at lower cost.
4. Aesthetics:
In
todays the appearance of fabric is getting more importance than the wear life.
Texture, drape and lustre are equally important parameters. All these
attributes can be imparted to fabrics by blending of fibres. Blending of fibres
with different length, denier, and colour and surface characteristics is used
to produce fancy yarns. Blending of fibres of different dyeing affinities is
done to achieve differential dyeing effects. Handle properties such as
fullness, firmness, smoothness and softness may be affected by blending.
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