APPAREL-INDUSTRY
(FLAX)
Hello Everyone!!!As we
are learning on fabric and various forms of fabric . First we gone through
cotton fabric and learn its complete formation process and its various fabrics
texture and family. Today we are going to discuss about Linen fabric. So
without wasting time let’s start….
HOW
LINEN IS MADE
Technically, linen is a vegetable. Linen fabric is made from the
cellulose fibers that grow inside of the stalks of the flax plant, or Linum usitatissimum, one
of the oldest cultivated plants in human history.
Flax is an annual plant, which means it only lives for one
growing season. From seed-planting, it is ready to be harvested in about a
hundred days. Unless the weather is particularly warm and dry, flax requires
little watering or attention during this time. It grows to about three or four
feet tall, with glossy bluish-green leaves and pale blue flowers, though on
rare occasions, the flowers bloom red.
Flax is cultivated around the world not only for its fine, strong
fibers, but also for its seeds, which are rich in nutrients such as
dietary fiber and omega-3 fatty acids. Flax oil is also a popular drying
oil amongst oil painters.
Types
of Flax
To date, no method of flax cultivation has been discovered that
maximizes both quality and yield of both seed and fibers. To obtain the highest
quality flax fibers, one must harvest before the plant fully matures, which
results in poorer-quality oil. Conversely, if harvest is undertaken after
maturation to obtain the best oil, the fiber quality deteriorates. Thus,
two distinct types of flax plants are cultivated:
·
The linseed variety is grown primarily to extract the
seed’s highly nutritious oil. This type is fairly short and produces many
secondary branches, which increases seed yield.
·
The flax variety tends to grow taller, more slender,
and with less branches. It is cultivated in order to extract the very long
fibers from inside the wooden stem of the plant, which are then
spun and woven into linen fabric. The taller the flax plant, the longer the
fiber.
Flax
Growing Environments
Flax can grow in a variety of climates, but it flourishes in
cool, damp environments. It cannot tolerate extreme heat, so the planting
schedule of flax varies from country to country depending upon regionalclimatic
conditions. For instance, in warmer regions flax is sown in the winter so that
harvesting can be undertaken before the heat of early spring. Because it
requires a lot of organic components, flax grows best in deep loams and
alluvial soils such as the Nile River valley.
Flax
Harvest
Flax is ready to be harvested for its fibers when the stem
begins to turn yellow and the seeds turn brown. On some farms however, the
plant is harvested prior to seed germination. This yields exceptionally fine fibers,
but leaves the grower without any seeds for the next planting and subsequently
dependent upon foreign imports.
Although the agricultural industry has made great strides in
mechanized farming, machine harvesting of flax is still unable to preserve the
root system during harvest. For this reason, despite the extremely laborious
process of manual harvesting, the highest quality linens are still made from
flax plants that were pulled out of the earth by hand.Fabric made from
hand-harvested flax is finer, more supple, and more highly prized than fabric
made from flax that is machine-harvested.
Traditional
Flax Processing. From Fibers and Seeds to Linen.
After harvest, flax stalks are allowed to dry in open air for
several weeks before they undergo threshing, or removal of seeds from the
stalk by crushing open the dried seed pods. Hand threshing is usually achieved
by simply beating the dried stalks until all the seed pods have been crushed,
then shaking the seeds free.
Flax fibers are considered bast fibers. Bast fibers are
fibers collected from the phloem, or the inner-bark of the plant. Fabrics
made from these fibers are typically quite strong and durable fabrics.
Aside from linen, a few other fabrics made from bast fibers include hemp,
ramie, and rattan.
What's
in a Flax Fiber?
You may remember from your Biology 101 class that the phloem is
one of the two vascular structures inside of plants that carry
nutrients throughout the organism (the other is the xylem, or the woody
core). Bast fibers are long, narrow supportive cells inside the phloem that
provide it with great tensile strength, but still allow flexibility of the
plant stem due to the fibers’ characteristic fiber nodes, or weak
pointsthat are distributed randomly along the length of the fiber. These fiber
nodes are also what make linen fabric flexible without being brittle.
Separating
Out the Flax Fiber
The xylem and phloem of plants are bundled together by calcium
ions and a sticky protein called pectin, which must be broken down in
order to separate the valuable bast fibers from the plant’s vasculature so that
they can beprocessed and spun into yarn. This is achieved via a process
called retting--or, literally, rotting. And yes, with the same awful
smell!
Retting
(a quick biology lesson from DeckTowel). Let's get technical.
The image to the right is a cross section of a bast fiber:
"X" is xylem; "P" is phloem; "C" is cortex;
"BF" is bast fibers.
How do these micro-organisms break down those sticky pectins? A
man named Sergei Winogradsky figured out the answer to this question back in
the 1890s. Winogradsky, a microbiologist and soil ecologist, is actually quite
famous for this answer - his discovery of chemosynthesis - a process
wherein autotrophs (organisms that make their own food) absorb carbon and
inorganic nutrients from their surrounding environments in order to mediate the
chemical reactions with which they create their own energy.
Prior to this discovery, scientists believed that all autotrophs
were dependent upon sunlight for energy production (remember photosynthesis?).
But Winogradsky found a little bacterium living in the root nodules of legume
plants that changed everything. He identified it as Clostridium
Pasteuranium, an obligate anaerobe that, by definition, cannot
survive in the presence of atmospheric oxygen (O2). The presence of this
autotrophic bacterium inside of the root nodules, without access to atmospheric
oxygen and therefore also without access to sunlight, led Winogradsky to
investigate how it managed to survive.
He found that C. Pasteuranium uses water molecules to
break up the sticky pectin bonds that hold the bast fibers to the phloem, a
process called hydrolysis. It then uses the chemical pieces of
the broken up pectins to create ammonia (NH3) out of free, bioavailable
nitrogen (N2) in its surrounding environment, which can then be utilized by the
bacteria in its metabolic processes. This is is called nitrogen fixation.
You’ve learned about it before this biology lesson (the nitrogen cycle),
and you’ve seen it with your own eyes (lightning).
Scientists have since isolated more than 22 different kinds of
autotrophic, pectin-dissolving bacteria from retted flax, mostly belonging to
the Clostridium family.
Methods
of retting
·
·
Water retting is the most widely-employed practice and
produces the highest quality fibers. It is best accomplished in stagnant or
slowly-moving waters, like ponds, bogs and streams. As a rule, the more
stagnant the water source, the more abundant the bacterial fauna and the faster
the retting process. Flax bundles weighted down in ponds and bogs generally ret
in anywhere from a few days to a couple of weeks, depending on water
temperature. Because the water is stagnant and the microfauna abounds, pond or
bog retting is particularly foul-smelling. Stream retting usually takes a few
weeks longer, but yields cleaner (and less stinky) fibers.
·
Dew retting is the preferred method in areas where water sources
are limited but that enjoy warm daytime temperatures and heavy nighttime dews.
Flax stalks are spread out evenly across a grassy field, where the combination
of air, sun and dew causes fermentation, which dissolves much of the stem
within 2-3 weeks. Dew-retted fibers are typically of poorer quality and more
darkly pigmented than natural water-retted fibers.
·
Tank retting takes place in large vats that are typically made
of cement, as the acidic waste products of the bacteria corrodes metal. Stalks
are first leached, or soaked, for 4-8 hours to removedirt and pigment from the
bundles. This water is then changed, and the bundles allowed to soak for 4-6
more days to complete the retting process.
·
Flax can also be retted chemically, which speeds up the process.
It is, however, more harmful to both the environment and the fibers themselves,
and is therefore not preferred.
Dressing
the flax
The retted stalks, called straw, are dried mechanically or in
natural air, and are then usuallystored for anywhere from a few weeks to months
in order to allow curing to take place. After curing, the woody stalks that
still cling to the bast fibers are further broken, usually by passing the
brittle straw through rollers that crush the wood into smaller pieces that can
be more easily removed, a process called scutching.
The separated bast fibers are next heckled, or combed
through a bed of nails that splits and polishes the fibers, and removes the
shorter tow fibers from the mix. These tow fibers can then be spun
into a coarse yarn from which low-quality linen products are made.
The longer fibers (sometimes as long as three feet!) are then
ready for spinning.
Spinning
The (at long last) separated flax fibers, called stricks,
are traditionally spun by hand using a distaff. A distaff is simply a long
vertical pole that attaches to a spinning wheel from which the fibers are hung.
This helps keep the fibers organized and prevents them from turning into a
tangled mess. Spinning involves twisting together the drawn out strands of
fiber to form yarns, then winding the yarn onto a bobbin, or spool. The yarn is
often slightly dampened duringspinning, which helps prevent fly-away strands
from escaping the twist and creates an especially-smooth yarn (check out this
really cool photojournal of a woman hand-spinning flax).
Flax is always spun very finely--especially the longest of the
fibers--resulting in a thin yarn. In order to create a thicker yarn, multiple
skeins of this thin yarn can be spun together, a process called plying.
You’ve probably heard this term before in reference to your toilet paper. One
ply: thin and sufficient. Two or more ply: preferred! The resulting yarn
(usually 3-ply or thereabouts) is typically finished by boiling for several
hours in soapy water, which gives it a nice shine.
Weaving
Linen yarn is generally woven into sheets--a process
wherein multiple threads are interlaced both horizontally and vertically on a
loom. Occasionally, linen yarn is also knit, or formed into fabric by
creating consecutive rows of loops that intertwine with one another. By virtue
of these loops, knit fabrics have a degree of stretch inherent in them, and
because linen yarn has no elasticity, it is quite difficult to knit and so more
frequently woven.
The Rise of the Machines
This pre-industrial method of linen production hasn’t changed in
centuries. Though over the last few hundred years we’ve developed machines that
complete the tasks of harvesting, retting and dressing flax, these processes
damage the delicate fibers such that finest linens are still manufactured
almost entirely by hand. Because the process is still so laborious, even
mechanized flax production actually requires a great deal more handwork than
other mass industrially-produced textiles like cotton and rayon.
Where
is the best quality linen made?
The quality of the linen fabric is greatly dependent upon the
retting process. For example, as you already learned, over-retting produces a
mushy, weak fiber, and under-retting makes the bits of shive difficult to
remove such that the fibers can be damaged during scutching; factors entirely under
the control of the retter. The secrets of flax processing have been passed down
throughout cultures for thousands of years , and the best linens tend to
originate from the enclaves within Europe that have long traditions of flax
cultivation:
·
The best quality linen is retted in slow-moving natural water
sources such as streams and rivers. In fact, the highest quality linen in the
world is retted in Belgium in the River Lys, though to this day
chemists have been unable to determine what makes the waters so conducive to
the retting process. Harvested flax is sent to Belgium from France, Holland,
and even as far away as South America to be retted in the magical waters of the
River Lys, which is typically crowded for miles with weighted down flax
bundles.
·
Irish linen is the best known and most valuable, though
most of the flax used for manufacturing is grown elsewhere and imported into
the country for processing. The climate in Ireland is quite favorable for flax
processing, and the slow Irish bleaching methods inflict minimal damage on the
fibers.
·
European linens are the next finest, with
the French producing the whitest and most delicate of
textiles. Scotch linen is generally considered of medium quality,
and German linen quality ranges from good to poor.
·
Flax is perhaps most widely cultivated
in Russia and China, though the fibers tend to be of poorer
quality than their European counterparts.
·
Smaller flax production centers exist
in Egypt, Northern Italy, parts of Canada and
the northernUnited States.
THE END
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