Monday, 23 December 2013

FLAX

Introduction:
Flax is used most largely in our textile manufactures. The linen fiber consists of the bast cells of certain species of flax grown in Europe, Africa, and the United States. All bast fibers are obtained near the outer surface of the plant stems. The pith and woody tissues are of no value. The flax plant is an annual and to obtain the best fibers it must be gathered before it is fully ripe. To obtain seed from which the best quality of linseed oil can be made it is usually necessary to sacrifice the quality of the fibers to some extent.

Treatment of Flax:
Unlike cotton, flax is contaminated by impurities from which it must be freed before it can be woven into cloth. The first process to which the freshly pulled flax is submitted is that of “rippling” or the removal of the seed capsules. Retting, next in order, is the most important operation. This is done to remove the substances which bind the bast fibers to each other and to remove the fiber from the central woody portion of the stem. This consists of steeping the stalks in water.
  • Retting:
(1) Cold water retting, either running or stagnant water.
(2) Dew retting.
(3) Warm water retting.
image
RETTING TANK
A—Inlet; B—Undisturbed Water; C—Bundles of Flax.
Cold water retting in running water is practiced in Belgium. Retting in stagnant water is the method usually employed in Ireland and Russia. The retting in stagnant water is more rapidly done, but there is danger of over-retting on account of the organic matter retained in the water which favours fermentation. In this case the fiber is weakened.
image
RETTING FLAX IN THE RIVER LYS, BELGIUM
image
FIBERS OF FLAX
In dew retting, the flax is spread on the field and exposed to the action of the weather for several weeks without any previous steeping. This method of retting is practiced in Germany and Russia. Warm water retting and chemical retting have met with limited success.
When the retting is complete, the flax is set up in sheaves to dry. The next operations consist of “breaking,” “scutching,” and “hackling” and are now done by machinery.
Breaking removes the woody center from the retted and dried flax by being passed through a series of fluted rollers. The particles of woody matter adhering to the fibers are detached by scutching.
  • Hackling:
Hackling or combing still further separates the fibers into their finest filaments—”line” and “tow.” The “flax line” is the long and valuable fiber; the tow, the short coarse tangled fiber which is spun and used for weaving coarse linen.
image
FLAX
A, Unthrashed Straw; B, Retted; C, Cleaned or Scutched; D, Hackled or Dressed.
image
HACKLING FLAX BY HAND
The “Tow” Is Seen at the Left and a Bunch of “Flax line” on the Bench.

  • Characteristics of Linen:
When freed from all impurities the chief physical characteristics of flax are its snowy whiteness, silky luster and great tenacity. The individual fibers may [Pg 50]be from ten to twelve inches in length; they are much greater in diameter than cotton. It is less pliant and elastic than cotton and bleaches and dyes less readily. Linen cloth is a better conductor of heat than cotton and clothing made from it is cooler. When pure, it is, like cotton, nearly pure cellulose.
  • Ramie:
Besides the linen, there is a great number of bast fibers fit for textile purposes, some superior, some inferior. India alone has over three hundred plants that are fiber yielding. One-third of these furnish useful fibers for cordage and fabrics. The next in importance to linen is ramie or rhea, and China grass. China grass comes from a different plant but is about the same as ramie. The staple is longer and finer than linen. The great strength of yarn made from it is due to length of the staple.
The variety and great value of the ramie fibers has long been recognized, but difficulties attending the separation and degumming of the fibers have prevented its employment in the manufactures to any great extent. The native Chinese split and scrape the plant stems, steeping them in water. The common retting process used for flax is not effective on account of the large amount of gummy matter, and although easy to bleach it is difficult to dye in full bright shades without injuring the luster of the fibers.
  • Jute and Hemp:
Jute and hemp belong to the lower order of bast fibers. The fiber is large and is unfit for any but the coarsest kind of fabrics. Jute is mainly cultivated in Bengal. The fiber is  separated from the plant by retting, beating, etc.
image
JUTE GROWING IN LOUISIANA.
image
DRYING HEMP IN KENTUCKY
  • Olona:
Olona, the textile fiber of Hawaii, is found to have promising qualities. This plant resembles ramie and belongs to the nettle family also, but it is without the troublesome resin of the ramie. The fiber is fine, light, strong, and durable.
The Philippines are rich in fiber producing plants. The manila hemp is the most prominent, of which coarse cloth is woven, besides the valuable cordage. The sisal hemp, pineapple, yucca, and a number of fiber plants growing in the southern part of the United States are worthy of note. These fiber industries are conducted in a rude way, the fiber being cleaned by hand, except the pineapple

No comments:

Post a Comment