KNOW ABOUT LINEN FIBRE - YARN & FABRIC

KNOW ABOUT  LINEN  FIBRE - YARN  & FABRIC 

Linen Fiber:
Linen is the most costly and luxurious of all the bast fibres, and has been valued for centuries for its exceptional coolness in hot weather. It has a very specific tactile appeal; it is smooth and lustrous to both the eye and hand, and the fibre is almost silky in texture, yet embodies a springy freshness.
Linen is such a desirable commodity that other textiles in a linen-weave texture, even when made of alternative non-flax fibers are also often loosely referred to as "linen". The slubs along the length of the yarn are sometimes considered an appealing characteristic of linen, and which are often present in other bast fibres, but are in fact technically a defect that denotes a lesser quality of yarn and fabric.
All bast fibres, and particularly linen tend to have good tensile strength which increases when wet. The fibres are hygroscopic, capable of absorbing up to 20% of their weight in moisture or perspiration, which is quickly releases into the atmosphere and is therefore dry to the touch, allowing the wearer to feel cool. This is because the structure of the fibre does not lock in or trap air and does not have any insulative properties. The slight stiffness of linen prevents textiles made from it from clinging to the body, and thus dries more quickly and eliminates perspiration. It is this inherent thermo regulating aspect that encourages the body to acclimatise in hot environments.
Linen, along with the other bast fibres generally have longer staple lengths relative to cotton, which makes them lint free. The quality of the final linen yarn and fabric is dependent upon the growing conditions, harvesting methods and whether it is a short fibre, known as tow or the more desirable long line fibre.

Linen tends to have very high durability and its qualities improve with age and laundering. The fibres become softer, stronger and brighter over time, enhancing its supple ‘polished’ sheen, however it can form breaks if repeatedly creased in the same place. Linen is also believed to have a slight anti bacterial function, as well as a capacity for resisting humidity.

Linen is a cellulosic fibers derived from the stem of the flax plant or a fabric made from these fibers. Linen fibers are much stronger and more lustrous that cotton; they yield cool, absorbent fabrics that wrinkle easily. Fabrics with linen-like texture and coolness but with good wrinkle resistance can be produced from manufactured fibers and blends. Properties/Characteristics of Linen Fiber:
Linen is comfortable, good strength, twice as strong as cotton, hand-washable or dry-cleanable, crisp hand tailors, well absorbent dyes and prints, well light weight to heavy weight, no static or pilling problems, fair abrasion resistant etc. Basically there are two types of properties of linen fibers. One is physical properties and another is chemical properties.

Physical Properties of Linen: 

Physical properties of linen fibers are given below:

1. Tensile Strength: Linen is a strong fiber. It has a tenacity of 5.5 to 6.5 gm/den. The strength is greater than cotton fiber.
2. Elongation at break: Linen does not stress easily. It has an elongation at break of 2.7 to 3.5 %.
3. Color: The color of linen fiber is yellowish to grey.
4. Length: 18 to 30 inch in length.
5. Lusture: It is brighter than cotton fiber and it is slightly silky.
6. Elastic Recovery: Linen fiber has not enough elastic recovery properties like cotton fiber.
7. Specific Gravity: Specific gravity of linen fiber is 1.50.
8. Moisture Regain (MR %): Standard moisture regain is 10 to 12%. 
9. Resiliency: Very poor.
10. Effect of Heat: Linen has an excellent resistance to degradation by heat. It is less affected than cotton fiber by the heat.
11. Effect of Sun Light: Linen fiber is not affected by the sun light as others fiber. It has enough ability to protect sun light.

Chemical Properties of Linen: 

Linen is a natural cellulosic fiber and it has some chemical properties. Chemical properties of the linen fiber are given below:

1. Effect of Acids: Linen fiber is damaged by highly densified acids but low dense acids does not affect if it is wash instantly after application of acids.
2. Effects of Alkalis: Linen has an excellent resistance to alkalis. It does not affected by the strong alkalis.
3. Effects of Bleaching Agents: Cool chlorine and hypo-chlorine bleaching agent does not affect the linen fiber properties.
4. Effect of Organic Solvent: Linen fiber has high resistance to normal cleaning solvents. 
5. Effect of Micro Organism: Linen fiber is attacked by fungi and bacteria. Mildews will feed on linen fabric, rotting and weakling the materials. Mildews and bacteria will flourish on linen under hot and humid condition. They can be protected by impregnation with certain types of chemicals. Copper Nepthenate is one of the chemical.
6. Effects of Insects: Linen fiber does not attacked by moth-grubs or beetles.
7. Dyes: It is not suitable to dye. But it can be dye by direct and vat dyes.

Major End Uses Linen Fabric:
Apparel:

• dresses, 
• suits, 
• separates, 
• skirts, 
• jackets, 
• pants, 
• blouses, 
• shirts, 
• children's wear etc.

Home Fashion :

• curtains, 
• draperies, 
• upholstery, 
• bedspreads, 
• table linens, 
• sheets, 
• dish towels etc
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  Cotton vs. Linen

   

  While cotton, from the cotton plant, and linen, from the flax plant, are both natural plant fibers (cellulose), there are many differences between them. The term "Linens" can colloquially refer to any household good, but this should not be confused with linen fabric. Below we compare cotton and linen in a non-exhaustive array of categories
  
  
  

  Strength and Longevity

  Linen is known to be the world’s strongest natural fiber. It is so durable it’s even used in paper money to increase strength! It is thicker than cotton and linen fiber has variable lengths, most of which are very long. This contributes to strength, which contributes to longevity. Linen lasts a very long time.
  The strength of cotton is achieved through spinning multiple fibers into yarn and weaving the yarn into fabric.
  

  Hand (referring to the way it feels in your hand)

  From the flax plant, Linen is a bast fiber. Known to be crisper than cotton, linen becomes supple through handling. It gains elegance and softens to behold the most fluid drape. Though it is has more natural texture than cotton, it is silky with high luster.
  Wrinkles? Both cotton and linen are associated with wrinkles. Linen fibers have a natural resin called lignan. At first, the fibers are stiff and crease easily. The wrinkles become smoother through handling and use.
  The Cotton plant yields fluffy fiber clusters called bolls. They are very soft to the touch and resilient to handling. Cotton fabrics can be very soft and no other plant fiber can offer the same type of comfortable hand at first touch.
  
  
  
   
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

  Interactivity with moisture

  Natural fibers love water. Linen is thought of as nature’s wicking fiber. It can gain up to 20% moisture before it will first begin to feel damp. Cotton will absorb more than 25% its weight in water.
  Additionally, linen is known to gain strength when wet. It has the natural ability to prevent bacterial growth. For towels, this is very important as hand and bath towels tend to be the perfect home for microbes.
  The affinity of cotton and linen to moisture is one reason why natural fibers are most comfortable to wear and to have in our bedrooms. They interact well with our bodies and contribute to our comfort.
  
  

  Warmth

  Linen fibers are hollow, moving air and moisture naturally. During the colder months, layer linen blankets or a throw to retain heat and warmth from your body. Linen reacts to the season and the body in contact with the cloth to give the best of all circumstances.  Linen is a natural insulator. It is valued for its ability to keep cool in the summer months and trap warmth in colder weather. This is all achieved through the natural properties of the fiber itself.
  Cotton blankets move effortlessly between seasons. Their warmth is found in the comfort of their feel. Innovative design and texture provide places for air, adding to comfort. During cold months, use cotton blankets and throws to layer. They will add weight. In warm climates, use a cotton blanket or throw alone and it will provide rest under the perfect weight. Your blankets have one job: to keep you warm, cozy and comfortably nested. Natural plant fibers outshine.
  

  Healthful Properties

  Known to help with everything from anti-stress to a better sleep, linen is thought to have healing properties and even reduce "itis" conditions (like arthritis and dermatitis).
  Ancient Egyptians used linen for its natural ability to help repel microorganisms. Linen has been known to be tolerable for those with allergies and to soothe skin conditions.
  
  

  Cotton and Linen have a long History:

  Linen textiles are some of the oldest in the world, dating back thousands of years. Egyptians sometimes used linen as currency.
  Use of the flax plant is believed to date back to approximately 8,000 BC. Cotton use has been around since prehistoric times. Specific evidence dates back to the Neolithic era from 6500 BCE to 2500 BCE. The Cotton Industry is one of the major successes in the Industrial Revolution.
  
  
  

  Washing Instructions

  All of our cotton, linen and merino wool products can be machine-washed and tumble-dried. Our alpaca and fine micron wool products must be dry cleaned.
  
• Wash separately in cold water on a short, gentle cycle, with as much water as possible to allow for movement.
• Avoid harsh detergents.
• Use a liquid detergent without bleach or brighteners.
• Always pre-dilute your detergent and clear any residue bleach.

Drying Instructions Per Fabric Type

 

100% Cotton

• Tumble dry on delicate setting, medium to high heat.
• Do not overdry

100% Linen

• Tumble dry on delicate setting, low or no heat.  Linen will become brittle if it is dried on high heat or for an extended period.
• Remove the product slightly damp from the dryer to “bake and break” the fibers. Allowing the fabric to rub on itself in a “dry” condition will cause abrasion.
• Tumbling keeps a soft drape. You can line dry, but the fabric will be stiff initially.
• Avoid exposure to direct sunlight over long periods.

50% Linen 50% Cotton 

• Tumble dry on a delicate setting, low to medium heat.
• Remove promptly.
• Do not overdry.

 

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 points that 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 be processed 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 malodorous process of retting can be achieved in a variety of ways, but it typically involves prolonged exposure of the stalk to moisture. Plants hold themselves upright by increasing water uptake into their cells, which causes the plasma membrane to swell and increases internal pressure against the cell wall. This pressure keeps the plant structures stiff (Biology 101 review: Turgor pressure). Prolonged water exposure during retting eventually causes the cells of the phloem to lyse, or burst open, and allows local micro-organisms that break down the sticky pectins to invade the plant cell.

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 remove dirt 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 usually stored 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.

Scutching involves scraping a small wooden knife down the length of the fibers as they hang vertically, pulling the broken woody bits away from the fiber. This is a labor-intensive process. One person scutching can produce only about 15 pounds of flax fibers per day; less if the fibers are coarse, hard, or have been poorly retted. The small pieces of leftover bark that remain after scutching are called shive, and are sometimes used as a filler in thermoplastic composites.

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 during spinning, 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.

   Wet spinning of flax yarn on cotton ring frame

If flax fibre can be produced with properties enabling it to be spun on a cotton system, it can open up the potentially high value markets for flax growers, processors and spinners, state Dr Prabal Majumdar and Achintya Samantaa, who provide the results of a project in spinning 100% flax yarn using ring frame. Flax fibre is extremely variable in length and difficult to control in its conversion into yarns. Many costly processes and much skill are involved in yarn-production[1]. Carefully-produced, good quality yarn is essential to produce a good quality fabric and to increase the efficiency of the loom. Certain improvements in fields of mechanisation and productivity have been made during 1950 - 1960 in the existing flax spinning system [2]. At present there is a demand for finer flax yarns, which is very difficult to produce with reasonable quality in the existing flax spinning system. New developments in the field of machining technology cannot be expected in the near future, due to high investment costs. Probably the most fundamental recent change in spinning techniques has been the application of ring spinning in the production of linen yarns. Still the fact remains that all the machinery use in flax spinning is far behind in productivity than the other textile industries like cotton and synthetic. The hurrying of flax yarn-production in the existing system can be dearly paid for at the later stage of weaving. In the processing of flax as a natural product, from a straw-like, agricultural product to a high value raw material for modern industrial sectors, development of processing technology is required, which facilitates a design of the fibres, corresponding to processing possibilities (cotton spinning), and the desired end-product (yarn) [3]. The requirement is that the profile of flax fibres should strongly resemble that of cotton, to avoid any extensive modifications of cotton machines [4]. Fibre length and fibre fineness are the two most important factors in the production of yarn on ring spinning machines. The similarity of cotton and flax filaments stimulated the idea of converting the flax fibre into a cottonised "cotton-like" fibre. The methods of adapting flax fibre to cotton processing methods consisted of obtaining a mass of thin filaments similar to cotton after destroying the adhesive complex of the middle layers for processing them with the cotton spinning system [5]. It is observed that good amount of splitting takes place after bleaching of the flax fibre, which is normally done in roving form. Considering this, it is expected that drafting in the ring frame would be easier and by proper control of the break draft the regularity of the yarn could be improved upon. The traditional processing system for bast fibres is outdated and economically unable to produce competitive products except in few isolated causes[6]. New techniques for processing bast fibres on conventional staple spinning system are to be developed with a view to utilise existing spinning equipment without the need for huge capital investment for specialised wet spinning machinery. In the present work efforts have been made to process the flax fibre on cotton ring frame and to select the proper spinning parameter for better spinning performance. Five different counts have been spun and their tensile and evenness characteristics have been studied in comparison with the yarn spun in the existing system. Experimental Materials and methods For this experiment 100% flax fibres have been used, which are imported from Belgium and France. Fibres are coming as a bale form. The bales are then opened and sorted as a bunch of approximately 80 gm. Sorted bunch are feed into the Hackling machine for removing sort fibre, other impurities and to parallelise the fibre. It produces a continuous sliver with a spreader. Length wise mixing of different grades of flax fibres is done in the first gill box passage. Six different grades of flax fibres mixed to prepare the sample material. Specifications of individual fibre are given in detail in Table 1. As there is no auto leveler in the conventional preparatory system, six passage of gill box has been used. Number of total doubling was 73728 (6 * 6 * 8 * 8 * 8 * 4). This high amount of doubling has been given to produce more even sliver for roving frame. Degumming of the prepared roving has been achieved by immersion of roving bobbin in a hot alkali (NaOH) solution with the aid of other auxiliaries such as sodium metasilicate, sodium sulphite and caustic solution. These auxiliaries help as a chelator for metal ions and also convey scouring properties. Further bleaching is achieved by application of hydrogen peroxide. It is also possible to discover changes with respect to the basic material. Hurds removed more easily. Fibres are purified. Unwanted fibre ingredients are largely removed. Whiteness of the fibre is increased. Another main objective of chemical treatment of the fibre at the roving stage is to achieve a degree of separation and breakdown of fibre bundles, which is sufficient to permit the wet-spinning process, whilst maintaining structural integrity of the roving under tension. This bleached roving is used as a feed material in ring frame. The details process parameters of the ring frame used for this test are given below: Name of the ring frame: TRYTEX miniature laboratory ring frame Drafting angle: 550 Spinning angle: 10.820 Back ratch setting: 62 mm Front ratch setting: 60 mm Lappet hook clearance: 3 mm Back bottom roller diameter: 28 mm Front bottom roller diameter: 28 mm Back, middle and front cots rollers diameter: 28.6 mm Ring diameter: 46 mm Traveler use: C type traveler Top arm type: SKF pk2025 c1 Front top Roller presser: 25 kg/cm2 Middle top Roller presser: 15 kg/cm2 Back top Roller presser: 25 kg/cm2 Wet flax fibre strand has a high tendency to lapping. In 45o drafting angle the length of spinning triangle is larger, which increases the chance of bottom roller lapping. Reducing spinning triangle by increasing the drafting angle to 55o has reduced the chance of bottom roller lapping as well as reduced the end breakage rate as it helps to propagate twist to the front roller nip. But increasing the drafting angle also increases the spinning angle, which influences the yarn hairiness. The other necessary changes made in the existing cotton ring frame are: Creel holder has been changed to suit for double flanged flax roving. Top apron from the main drafting zone has been removed and used only cots roller over bottom apron. A lap catcher has been incorporated over the front top roller to prevent the top roller lapping as wet flax strand has a high tendency to lap over the relatively smaller size top roller. From the bleached wet roving bobbins, five set of counts have been produced, which are generally run in the industries. In linen count system (lea) those are 25 lea, 50 lea, 60 lea, 80 lea and 85 lea. The different ring frame parameters used for different counts are given in Table 2. At the time of experiment it was found that break draft of 1.3 gave satisfactory spinning performance. Break draft below this has shown frequently occurrence of slabs, which increases the yarn faults and ends-down rate. For courser count range twist multiplier of 2.5 gave good running performances, whereas in case of medium count range it was minimum 2.8 and for finer count it was minimum 3.0, which gave satisfactory spinning performance. Testing As a single material sows different properties in different atmospheric condition so it is important that all the samples, prior to testing, are conditioned in a standard atmospheric condition. All yarn bobbins were dried in drying chamber at 900C temperature for 1 hour and 30 min and subsequently conditioned at 200C and 65% RH for 4 hr. Condition samples were tested on USTER® TENSORAPID 4 for determining: Tenacity (Rkm) Elongation (%) Breaking force (lbf) In all the cases gauge length has been kept at 500 mm and elongation rate at 500 mm/min. As finer yarns are giving more unevenness and more imperfection so, only 60 lea, 80 lea, and 85 lea yarns are tested for evenness testing. USTER TESTER 3 has been used for determining yarn evenness characteristic. Testing speed was set in 400 m/min and testing time set for 1 min. Properties measured are: U% Thin place/km Thick place/km Neps/km Hairiness index To compare the prepared sample with the conventionally spun yarn, equivalent count of conventionally spun yarn has been tested for the same parameters. Result and discussion The tensile testing results of the cotton system spun samples and conventionally spun yarns are given in Tables 3 and 4. In this experiment yarn tensile properties are represented by their breaking strength and Rkm values. Table 3 and Figure 1 (a, b, c) show that Yarn strength and elongation properties are not that much affected by changing the processing system. In coarser count range cotton system spun yarn shows relatively higher strength whereas in finer count ranges conventional system spun yarn shows a little greater strength. In case of elongation% almost in all count, spun in cotton system ring frame shows a little higher value. The low twist level compared to the conventional system, in finer yarn though gives sufficient strength to achieve good spinning performance in cotton system ring frame, it shows lower strength and higher elongation% than the conventionally spun yarn. High storing time of wet roving samples may be the other cause of decrease in the strength of individual fibres. As individual fibre strength ultimately affects the yarn strength so yarn strength also decreases. Fibre alignment in the yarn strand also plays a role in determining the yarn elongation. If fibres are more parallel to the yarn axis then it shows higher elongation as effect yarn elongation is also more. In the cotton system ring frame, the provision of applying break draft increases the parallelisation and better alignment of individual fibre in the yarn strand, which ultimately increases the yarn elongation and strength. From Table 5 it can be observed that in case of 60 lea (22.38 Ne) U% value, thin place (-50%), neps (+200% & +400%) has been less than the other finer count but the hairiness increases more than the other finer count. So finer the yarn count, higher is the unevenness and imperfections level but lower the hairiness index, which matches with the common behaviour of ring frame spun yarn. Occurrence of thick place (+50%) has not shown any trend in variation within the count. From Figures 2, 3 (a, b, c, d), and 4 it observed that occurrence of U%, thick place (+50%), thin place (-50%), and hairiness is high in cotton ring frame spun yarn than in conventionally spun yarn. But occurrences of neps both in +200% levels and +400% levels have been reduced. In the drafting zone when the flax cells are separated from each other there is no positive control over it. Proper wetting system helps in good splitting of the individual cell. With the absence of proper wetting system for the roving strand in the laboratory ring frame, the fibres are not separated from each other uniformly along the drafted strand and so occurrence of unevenness and thick-thin faults is more. As the number of fibre in the yarn cross section is less in the case of finer yarn so amplitude of fault is more in case of finer yarn. Uncontrolled atmospheric condition is also responsible for increasing yarn faults in the experimental procedure. As drafting angle increases, spinning angle also increases. So edge fibres in the strand are not trapped into the yarn structure and create hairiness. Using of light weight traveler in the experiment increases the hairiness of the yarn as it increase the balloon dimension. Frictions of yarn with the balloon control ring and lappet guide increase the hairiness. In conventional system there is no balloon control ring and lappet design is also different; so it reduces the yarn abrasion and also the chance of yarn hairiness. As in cotton system ring frame break draft is applied first and then the fibre enter the comparatively high draft zone, so in break draft zone curled and criss-crossly arranged fibre tries to align themselves on the strand axis. This aligned fibre drafted easily in the main drafting zone reduces the chance of fibre breakage and formation of neps. Conclusion It can be now concluded that: It is possible to spin the flax yarn successfully in cotton system ring frame. One can easily get the benefit of versatility and auto motion developed in cotton system ring frame in the production of flax yarn, and produce quality yarn with high productivity. Spindle speed can be increased up to 7,000 rpm without affecting the spinning performance. Whereas in conventional spinning the spindle speed can be increased up to 6,300 rpm keeping the good spinning performance. Twist multiplier (in Ne system) of 2.5 for courser count, 2.8 for medium count and 3.0 for fine count gives satisfactory spinning performance. It can be set to higher side for improving the yarn strength. But it will reduce the yarn elongation. Break draft of 1.3 is found suitable for all the count range. In case of coarser yarn, tenacity is better than the finer count. Elongation% is better in cotton system spun yarn than in the conventionally spun yarn for all counts of yarn. U%, thick place, thin place and hairiness increase in cotton system ring frame spun yarn. Occurrence of neps of +200% & +400% is reduced in cotton ring frame spun yarn compared to the conventionally spun yarn. Generation of fly – flap is reduced in cotton system ring frame, which is a major problem in conventional ring frame.

•  https://vimeo.com/40402198
  
  
  Courtesy :ITJ May 2012
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