Silk - the most beautiful of all textile fibers is acclaimed as
the queen of textiles. Silk comes from
the cocoon of the silk worm and requires a great deal of handling and
processing, which makes silk one of
the most expensive fibers also. Today China is the leading silk producer of
the world. Other major silk producing countries include Japan, India,Bangladesh
and Italy.
Now I will discuss about Silk such as :-
Production of Silk
Characteristics of Silk
Identifying of Silk
Four Varieties of Natural Silk
The Silk Worm :
Production of Silk from Cocoon to
Factory :
Sericulture:
The production of
cocoon for their filament is called sericulture. The species Bombyx mori is
usually cultivated and is raised under controlled condition of environment
and nutrition. The life cycle of silk worm encircle in the four stages. The
egg, the silk worm, the pupa and the moth. The silk worm which feeds on
mulberry leaves forms a covering around it by secreting a protein like
substance through its head.
This stage is called
cocoon, the desirable stage for the silk producers.
Filature operations:
The cocoons raised by the farmer are
delivered to the factory, called a filature, where the silk is unwound from
the cocoons and the strands are collected into skeins. Some cocoons are
scientifically bred in such factories. The filature operations consist of the
following stages.
a) Sorting cocoons :
The cocoons are sorted according
to the color, size, shape and texture as these affect the final quality of
the silk. Cocoons may range from white and yellow to grayish.
b) Softening the Sericin :
Silk filament is a double strand
of fibroin, which is held together by a gummy substance called sericin or
silk gum. After the cocoon has been sorted, they are put through a series of hot and cold immersions, as the sericin must
be softened to permit the unwinding of the filament as one continuous thread.
c) Reeling the filament :
Reeling is the process of unwinding the silk filaments from the cocoon
and combining them together to make a thread of raw silk. As the filament of
the cocoon is too fine for commercial use, three to ten strands are usually
reeled at a time to produce the desired diameter of raw silk which is known
as "reeled silk". The useable length of reeled filament is 300 to
600 m.
d) Bailing :
The silk filament is reeled into
skeins, which are packed in a small bundles called books, weighting 2 to 4.5
kg. These books are put into bales weighing about 60 kg. In this form raw
silk is shipped to silk mills all over the world.
Characteristics of Silk
Silk is very strong in terms of tensile strength, meaning silk can withstand
a lot of pulling type pressure without breaking. This should not, however, be
confused with wear ability or abrasion resistance. Silk will not stand up to
the heavy wear that other fibers will.
Silk can take on many different appearances. A raw silk fabric
may fool you into thinking that it is cotton or synthetic. The more refined
the silk and the smaller the yarn, the more it resembles the look and feel
that we know as silky.
Silk is a protein fiber like wool. This gives it many of its
characteristics. It is sensitive to a range of chemical situations and cannot
withstand prolonged exposure to either high alkalinity or to acid or oily
soils. It will become brittle with age and exposure to sunlight.
Identifying Silk
The burn test is the best way to be sure. Burning silk will leave a powdery
ash and will extinguish itself when the flame is removed, just like wool. The
easy way to tell silk and wool apart in the burn test is the smell. Where
wool will have the smell of burning hair, the silk will have a much more
disagreeable smell.
Four Varieties of Natural Silk
Out of the numerous species of silk moths, scientists have enumerated about
70 silk moths which are of some economic value. But of these only a very few
have commercial value.
The four commercially known varieties of natural silk are
(1) Mulberry silk
(2) Tasar silk
(3) Muga silk
(4) Eri silk.
Although the bulk of
world silk supply comes from the silk moth Bombyx Mori which is domesticated,
the other varieties of silk are known as wild silk, as they are grown in
remote forest trees in natural conditions
|
No comments:
Post a Comment