Linen

30 06 2010

Linen is a textile made from the fibers of the flax plant, Linum usitatissimum L., which is a delicate and graceful annual that stands about 3 feet high and produces attractive blue flowers. Its Latin name means “most useful,” and for good reason. Though technically a wildflower, flax  has been cultivated for thousands of years for a wide variety of important uses.  Common flax was one of the earliest domesticated plants.  A cousin of hemp, cannabis sativa L., flax is also known as a “bast” plant, meaning the fiber is collected from the inner bark, or bast,  of the steam. 

Flax  grows best at northern temperate latitudes, in cool,  humid climates and within moist, well-plowed soil.

Today, France, Belgium, Netherlands, Spain, Russia, Egypt and China are the foremost producers of flax for commercial textile purposes.   China is also a major buyer of raw flax for processing, with imports of 60 000 tons a year, including most of Europe’s flax fibers. Bulk linen production has shifted to Eastern Europe and China, but niche producers in Ireland, Italy and Belgium continue to supply the market for high quality fabrics in Europe, Japan and the USA.

There are two main types of flax grown worldwide:  fiber flax and seed flax.

FIBER FLAX:

Flax is one of the oldest fiber crops in the world.  It was used by the ancient Egyptians, Romans, Greeks and Hebrews for food, clothing and medicine.

The use of flax fiber in the manufacturing of cloth in northern Europe dates back to Neolithic times. In North America, flax was introduced by the Puritans, and today has become an essential commercial crop grown throughout the Midwest.

Today, flax is used to make linen cloth,  and it’s usually an expensive textile, produced in relatively small quantities.  Linen fabric maintains a strong traditional niche among high quality household textiles – bed linen, furnishing fabrics, and interior decoration accessories.  More than 70% of linen goes to clothing manufacture, where it is valued for its exceptional coolness in hot weather – the legendary linen suit is a symbol of breezy summer elegance.

Linen has a long staple (i.e., individual fiber length).  The best grades of flax  are used for fine fabrics such as damasks, lace and sheeting. Shorter flax fibers produce heavier yarns suitable for kitchen towels, sails, tents and canvas.  Lower fiber grades are used as reinforcement and filler in thermoplastic composites and resins used in automotive interior substrates, twine, rope,  furniture and other consumer products.  Flax fiber is also a raw material for the high-quality paper industry for the use of printed banknotes and rolling paper for cigarettes and tea bags.   Linen fabric is one of the preferred traditional supports for artists canvas. In the United States cotton is popularly used instead because linen is many times more expensive, restricting its use to professional painters. In Europe however, linen is usually the only fabric support available in art shops. Linen is preferred to cotton for its strength, durability and archival  integrity.

SEED FLAX:

Flax seed is grown for human and animal consumption. Flax seeds can be eaten raw or cooked, cracked or whole, and can be ground into flour. They are often sprinkled on top of bread, cooked into foods like chips, muffins and cakes or added to granola cereal. Flax seeds contain high amounts of Omega-3, 6 and 9 fatty acids, which are believed to reduce cholesterol, boost the immune system and lower the risk of heart disease. They also contain potassium, magnesium, fiber and protein, and make a good natural laxative.                    

Flax seed oil (also called linseed oil) is used for culinary as well as industrial purposes.  A good source of essential omega-3 fatty acids, the oil is believed to provide benefits to arthritis and lupus patients by reducing inflammation.   For industry, it serves as a pigment binder for oil paint and a drying agent for paints, lacquers and inks. It is sometimes used as a wood finish, in varnishes, printing inks, and soaps and can be combined with cork to make linoleum.

Once oil is cold pressed from flax seeds, the husks, which are high in protein,  are often used as feed for chickens and other livestock. The seeds provide animals with much needed fiber and protein. Eggs from chickens that were fed flax seeds are  purported to be high in omega fatty acids and have added health benefits.

Flax  fibers range in length up to 90 cm, and average 12 to 16 microns in diameter.  They are not as long as hemp, which has fibers that measure from 90 cm to 460 cm, yet they are much longer than cotton fibers, which measure only as much as 3.5 cm.
Harvesting:

There are three degrees in the ripening of the flax grown to make linen: green, yellow and brown. The yellow has proved to be the most suitable for fiber production. Flax that is pulled too early – green – produces very fine but weak fibers. On the other hand, in overripe flax – brown – the stems are strong but brittle and produce too high a proportion of undesirable short fibers (‘tow’). When the flax is yellow, the fibers are long and supple, and therefore ideal for further processing.  (This is where we get the term “flaxen” to describe a yellow haired person.) The plant must be harvested as soon as it appears ready since any delay results in linen without the prized luster.  It is important that the stalk not be cut in the harvesting process but removed from the ground intact; if the stalk is cut the sap is lost, and this affects the quality of the linen.

These plants are often pulled out of the ground by hand, grasped just under the seed heads and gently tugged. The tapered ends of the stalk must be preserved so that a smooth yarn may be spun. The stalks are tied in bundles (called beets) and are ready for extraction of the flax fiber in the stalk. However, fairly efficient machines can pull the plants from the ground as well.

Once the plants have been harvested, the fibers must be released from the stalk.  This process is called “retting” – actually a process of rotting away the woody bark of the plant which also loosens the pectin or gum that attaches the fiber to the stem:

  • Retting may be accomplished in a variety of ways. In some parts of the world, linen is still retted by hand, using moisture  to rot  away the bark. The stalks are spread on dewy slopes, submerged in stagnant pools of water, or placed in running streams. Workers must wait for the water to begin rotting or fermenting the stem—sometimes more than a week or two. However, most manufacturers today use chemicals for retting. The plants are placed in a solution either of alkali or oxalic acid,  then pressurized and boiled. This method is easy to monitor and rather quick, although some believe that chemical retting adversely affects the color and strength of the fiber and hand retting produces the finest linen. Vat or mechanical retting requires that the stalks be submerged in vats of warm water, hastening the decomposition of the stem. The flax is then removed from the vats and passed between rollers to crush the bark as clean water flushes away the pectin and other impurities.
  • If flax is not fully retted, the stalk of the plant cannot be separated from the fiber without injuring the delicate fiber. Thus, retting has to be carefully executed. Too little retting, or under retting,  may not permit the fiber to be separated from the stalk with ease; it produces a coarse yarn suitable only for ropes.  Too much retting (over retting or rotting) will weaken fibers so they will have limited application.  The value of a batch can vary by 100% depending on the quality of the retting.
  • After the retting process, the flax plants are squeezed and allowed to dry out before they undergo the process called breaking. In order to crush the decomposed stalks, they are sent through fluted rollers which break up the stem and separate the exterior fibers from the bast that will be used to make linen. This process breaks the stalk into small pieces of bark called shives. Then, the shives are scutched. The scutching machine removes the broken shives with rotating paddles, finally releasing the flax fiber from stalk.
  • The fibers are now combed and straightened in preparation for spinning. This separates the short fibers (called tow and used for making more coarse, sturdy goods) from the longer and more luxurious linen fibers. The very finest flax fibers are called line or dressed flax, and the fibers may be anywhere from 12-20 in (30.5-51 cm) in length, but first class fibers are at least 60 cm.   Color of light grey, steel grey and silver grey are considered the best.

Spinning:

  • Line fibers (long linen fibers) are put through machines called spreaders, which combine fibers of the same length, laying the fibers parallel so that the ends overlap, creating a sliver. The sliver passes through a set of rollers, making a  roving which is ready to spin.
  • The linen rovings, resembling tresses of blonde hair, are put on a spinning frame and drawn out into thread and ultimately wound on bobbins or spools. Many such spools are filled on a spinning frame at the same time. The fibers are formed into a continuous ribbon by being pressed between rollers and combed over fine pins. This operation constantly pulls and elongates the ribbon-like linen until it is given its final twist for strength and wound on the bobbin. While linen is a strong fiber, it is rather inelastic. Thus, the atmosphere within the spinning factory must be both humid and warm in order to render the fiber easier to work into yarn. In this hot, humid factory the linen is wet spun in which the roving is run through a hot water bath in order to bind the fibers together thus creating a fine yarn. Dry spinning does not use moisture for spinning. This produces rough, uneven yarns that are used for making inexpensive twines or coarse yarns.
  • These moist yarns are transferred from bobbins on the spinning frame to large take-up reels. These linen reels are taken to dryers, and when the yarn is dry, it is wound onto bobbins for weaving or wound into yarn spools of varying weight. The yarn now awaits transport to the loom for weaving into fabrics, toweling, or for use as twine or rope.

A great concern to the environment is the chemicals used in retting. These chemicals must be neutralized before being released into water supplies. The stalks, leaves, seed pods, etc. are natural organic materials and are not hazardous unless impregnated with much of the chemicals left behind in the retting process. The only other concern with the processing of linen is the smell—it is said that hand-retted linen produces quite a stench and is most unpleasant to experience.

The first flax-spinning mill was opened in England in 1787, but only in 1812 was linen successfully woven with power looms. The linen industry suffered in relation to cotton because many textile inventions were not applicable to linen.   Although linen exceeds cotton in coolness, luster, strength, and length of fiber, the expense of production limits its use.

The decrease in use of linen may be attributed to the increasing quality of synthetic fibers, and a decreasing appreciation of buyers for very high quality yarn and fabric. Very little top-quality linen is produced now, and most is used in low volume applications like hand weaving and as an art material.

Over 90% of the world’s spinning equipment are designed to quickly and effectively spin fibers based on the length and diameter of cotton fibers.  This is referred to as the “cotton” system.  No other spinning system is as productive or cost-effective as the cotton system.  Flax fibers can be broken down into their shortest components, and this is called cottonization and the product is called cottonized flax.  Flax has traditionally been cottonized using mechanical systems (i.e., mechanical cottonization) but it can also be done using enzymes, steam explosion and ultra-sound.  This “cottonization” is done to be able to spin linen fibers on cotton machines – it means the process is quicker and requires less equipment.  However, the finished fibers often lose the characteristic linen look.

The Living Linen Project was set up in 1995 as an Oral Archive of the knowledge of the Irish linen industry still available within a nucleus of people who were formerly working in the industry in Ulster.  There is a long history of linen in Ireland.

For those of you with linguistic interests, linen has given rise to a number of words:

  • line, derived from the use of a linen threadto determine a straight line;
  • liniment, due to the use of finely ground flax seeds as a mild irritant applied to the skin to ease muscle pain
  • lining, because linen was often used to create a lining for wool and leather clothing
  • lingerie, via French, originally denotes underwear made of linen
  • linseed oil, an oil derived from flaxseed
  • linoleum, a floor covering made from linseed oil and other materials

CHARACTERISTICS of Linen:

Linen is among the strongest of the vegetable fibers, with 2 to 3 times the strength of cotton.  It is a very durable, strong fabric, and one of the few that are stronger wet than dry. It is smooth, making the finished fabric lint free, and gets softer the more it is washed.  The fibers  are resistant to damage from abrasion.

However, constant creasing in the same place in sharp folds will tend to break the linen threads. This wear can show up in collars, hems, and any area that is iron creased during laundering. Linen has poor elasticity and does not spring back readily, explaining why it wrinkles so easily.

Linen fabrics have a high natural luster; their natural color ranges between shades of ivory,  ecru,  tan, or grey. Pure white linen is created by heavy bleaching. Linen typically has a thick and thin character with a crisp and textured feel to it, but it can range from stiff and rough, to soft and smooth.

When freed from impurities, linen is highly absorbent and will quickly remove perspiration from the skin. Linen is a stiff fabric and is less likely to cling to the skin; when it billows away, it tends to dry out and become cool so that the skin is being continually touched by a cool surface.  It’s valued for its exceptional coolness and freshness in hot weather.

Mildew, perspiration, and bleach can also damage the fabric, but it is resistant to moths and  carpet beetles. Linen is relatively easy to take care of, since it resists dirt and stains, has no lint or pilling tendency, and can be dry cleaned, machine washed or steamed. It can withstand high temperatures, and has only moderate initial shrinkage.

Linen should not be dried too much by tumble drying: it is much easier to iron when damp. Linen wrinkles very easily, and so some more formal linen garments require ironing often, in order to maintain perfect smoothness. Nevertheless the tendency to wrinkle is often considered part of the fabric’s particular “charm”, and a lot of modern linen garments are designed to be air dried on a good hanger and worn without the necessity of ironing.

A characteristic often associated with contemporary linen yarn is the presence of “slubs”, or small knots which occur randomly along its length. In the past, these slubs were considered defects associated with low quality. The finest linen had very consistent diameter threads, with no slubs.  Today, however, the presence of slubs is considered appealing, and fashion dictates that even the finest linens have these slubs.

Advertisements




Characteristics of hemp

2 06 2010

We were charmed by this quote, which was written by Yitzac Goldstein of Earth Protex, many years ago:

Before Huang-Ti’s time                                      
clothing was made from skins of birds and animals.

But as time went on

people increased and animals were few

Causing great hardship.

So Huang-Ti ordained that

Clothing should be made from hemp fiber.

This is how the spiritual leader  changed matters

For the people’s benefit.

6th century A.D. historian Khung Ying-Ta on

The Yellow Emperor, Huang-Ti, 27th century B.C.

I love hemp, maybe just because of the lore associated with the plant – and I don’t mean the lore surrounding the hallucinogenic properties of the plants that are bred for high THC content!  So let’s get that part out of the way fast:

Hemp is another word for the plant Cannabis sativa. Yes, marijuana comes from this same plant genus – and so does hops, used to produce beer for millennia. But what we call “industrial hemp” is a different variety (or subspecies), called Cannabis sativa sativa.  Marijuana is from Cannabis sativa indica, which is bred to contain between 5 – 10% of the intoxicating substance delta-9 tetrahydrocannabinol, or THC.  Industrial hemp, Cannabis sativa sativa, contains less than one tenth that amount.  Industrial grade hemp is not marijuana – it doesn’t look the same and if you tried to smoke it you’d probably die of carbon monoxide poisoning before you felt anything but sick. For more about the differences between the two varieties click here or go to the Industrial Hemp website.

Hemp is unique among other crops in that every part of the plant has utility and potential market value.  Here are some interesting facts about hemp that contribute to the lore I’m referring to:

  • In 1941 Henry Ford built a car with a plastic made from hemp and wheat straw.
  • Both George Washington and Thomas Jefferson grew hemp on their plantations; in fact the colonial government mandated that people grow hemp.  Settlers used hemp fiber as money and to pay taxes.
  • The original Levi Strauss jeans were made from hemp.
  • The July 4, 1776 Declaration of Independence  was written on hemp paper.

The plant has been used for millennia for food, fibers and fuel.   Today it is said that over 30,000 different products can be made from hemp.  Hemp’s oilseed makes high-grade food and beauty products.  The stalks produce fiber and cellulose.  And today, because of its length and strength, hemp fiber is woven into natural advanced composites, which can then be fashioned into anything from fast food containers to skateboard decks to the body of a stealth fighter.  There are over two million cars on the road today with hemp composite components.

But hemp for luxurious fabrics?  I remember those macramé plant hangers that were all the rage in the 1970’s.  Hemp has a public relations campaign to wage, because when I thought of hemp a few years ago (before my enlightenment) all I could imagine was burlap bag and sisal rugs.  Turns out the technical revolution has even found hemp:  new developments from the 1980’s  in retting and processing the stalks has meant that the hemp fibers produced today are soft and lustrous enough for even the finest fabrics.

Many end users look for comfort and durability in choosing a fabric, so hemp’s softness and high abrasion resistance make it a competitive choice.  Hemp fiber’s positive qualities have been recognized over thousands of years of real life applications.  The texture of pure hemp textiles resembles that of flax linen, appealing to the eye with its subtle variations in thickness, but it is also versatile and can be blended with other fibers to create many different looks.  Hemp’s versatility as a textile is stunning:  hemp fibers can be woven alone or with other fibers to produce weaves from rugged canvas to the lightest, silkiest  gauze,  in an unlimited array of colors and finishes.  Hemp has a beautiful natural luster and a lush hand and drape not found with any other natural or synthetic fiber, even linen.

Hemp’s characteristics as a textile make it a desirable choice in many applications:

  • Hemp is stronger and more durable than any other natural fabric, including linen, which almost matches hemps abrasion resistance and tensile strength.  The result is that hemp has a longer lifespan than other natural fabrics.[1] (Patagonia is just one of the many companies which has published studies which demonstrate hemp’s superior strength; results for these studies range from 3 to 8 times stronger.)  Products made from hemp will outlast their competitors by many years.
  • Not only is hemp strong, but it also holds its shape, stretching less than any other natural fiber. This prevents hemp fabric used in upholstery, demountable panels, acoustic paneling or as wallcovering from stretching out or becoming distorted with use.
  • Hemp fabric withstands, even benefits from, commercial laundering. Its inherent luster and light reflective qualities are enhanced by washing; it becomes finer and more luxurious with use. Hemp also possesses excellent soil-release properties because it sheds a microscopic layer each time it is laundered. This eliminates soiling and exposes a fresh surface. In effect, this means that hemp retains its sleek sheen every time it is washed, that it never dulls, and that it releases stains more easily than other fabrics.
  • Hemp may be known for its durability, but its comfort and style are second to none.  The more hemp is used, the softer it gets: it wears in, not out, thriving on regular use and machine washing without suffering fabric degradation. Hemp actually becomes softer, more resilient and more lustrous as a result of washing.
  • Hemp’s superior absorbency, due to its porous nature, means that it is very breathable and quick drying. Hemp can absorb up to 20% its own weight while still feeling dry to the touch (vs. polyester, which can absorb a maximum of 6%). This is important in the case of any fabric that is in contact with human skin, such as sheets, as perspiration is rapidly absorbed. It feels cooler in summer yet during cool weather, air which is trapped in the fibers is warmed by the body, making it naturally warm.
  • Hemp’s absorbency allows it to accept dyes readily and retain color better than other natural fibers, including cotton.
  • Hemp has a high resistance to ultraviolet light; it will not fade or disintegrate from sunlight as quickly as other natural fibers. (Tilly Endurables introduced a new hat in 2004 after testing its hemp fabric to a UPF of 50+, the maximum ultraviolet protection rating given.[2]) UV damage is especially a problem for draperies and marine interiors, so hemp would be a good natural fiber choice for these applications.
  • Hemp fiber is highly resistant to rotting, and its resistance to mildew, mold and salt water led to its premier use in marine fittings:  the majority of all twine, rope, ship’s sails, rigging and nets up to the late 19th century were made from hemp.  The word canvas itself is derived from cannabis.
  • Finally, any product made of hemp is fully biodegradable and easily recyclable.

Hemp as a crop is also a standout.  The bio-regional model of agriculture focuses on obtaining high value for the resources of the local land, recycling the waste and end products ad infinitum and thereby creating a “closed circle” of farming and industry.  Hemp is an elegant solution to the crises created by modern agribusiness and conventional cotton production because:

  • Hemp grows well without the use of chemicals:  usually no pesticides or fungicides are used because it has few serious fungus or pest problems – although the degree of immunity to attacking organisms has been greatly exaggerated.  Several insects and fungi specialize exclusively in hemp!  But despite this, the use of pesticides and fungicides are usually unnecessary to get a good yield.    No herbicides are generally used because dense plantings shade out weeds; no defoliants are needed (as they are with machine harvested cotton) because the dried foliage is not a problem for harvesting.
  • Hemp requires less water to thrive than cotton – is actually drought tolerant –  and usually grows well without irrigation.  Globally, 77% of cotton crops are irrigated.
  • Hemp has a fiber yield higher than any other agricultural crop, thereby requiring less land for equal yield:

Average fiber production, in pounds, per acre:

Conventional cotton Organic cotton Flax Wool Hemp
121 – 445 lbs. 80  –  102 lbs. 323 – 465 lbs. 62  lbs. 485 – 809 lbs.

Source: UK-government funded project at University of London, “Demi: design for sustainability” (www.demi.org.uk), © Kate Fletcher, 1999

This yield translates into high biomass, which can be converted into fuel in the form of clean-burning alcohol, or no-sulphur man-made coal.

The most widespread claim for the environmental friendliness of hemp is that it has the potential to save trees that otherwise would be harvested for the production of pulp.  If  hemp reduces the need to harvest trees for building materials or other products, its use as a wood substitute will tend to contribute to preserving biodiversity.  Hemp may also enhance forestry management by responding to short-term fiber demand while trees reach their ideal maturation. In developing countries where fuel wood is becoming increasingly scarce and food security is a concern, the introduction of a dual-purpose crop such as hemp to meet food, shelter, and fuel needs may contribute significantly to preserving biodiversity.

For more on hemp, here are some resources to get you started:

Organizations

Web

Journals

  • Journal of the International Hemp Association. Vol. 1 (1994)–Vol. 6 (1999). (Vols. 1–5 and part of Vol. 6 available online at mojo.calyx.net/~olsen/HEMP/IHA/). Superseded by Journal of Industrial Hemp.
  • Journal of Cannabis Therapeutics. Hawarth Press. Vol. 1 published 2001.
  • Journal of Industrial Hemp. Haworth Press. Vol. 1 to be published 2002.

[1] Kerr, Nancy, PhD, “Fabulous Fibers? Can hemp compete with natural and manufactured fibers?” AgFibe2002 conference, Winnipeg, MB, Nov. 13 – 15, 2002.

[2] Press release, Tilly Endurables 2004; also see http://www.backpackgeartest.org/News/article.php?story=20050210193045692.