Linen: The Manufacturing Process and How to Care for Linen Fabrics
Linen fiber is a cellulose fiber derived from the flax plant trunk. Linen yarn is woven from the long fibers found behind the bark in a multi-layered stalk of the flax plant. In order to restore cellulose fibers from the plant, the wooden trunk and the inner pith (pectin), which binds the fibers together in a clump, must be eliminated away. Cellulose fibers are then ready for spinning.
Linen fiber is one of the most strength of natural fibers. It is also comfortable and still widely used.
The largest exporters’ countries of flax yarns are China, Italy, Tunisia, and Lithuania, along with other high-quality linen fabrics producers such as Ireland, Belgium, Poland, Austria, France, Germany, Sweden, Denmark, Belarus, Latvia, the Netherlands, Spain, Switzerland, and India.
Linen, Ancient Egypt
Brief History of Flax Fibres
Archaeologists discovered the oldest flax fibers at an upper-Palaeolithic excavation site at Dzudzuana Cave in the eastern-European country of Georgia. That fiber was kept in pollen chambers for 34,000 years.
After that simply-woven linen cloth of 9,000-year-old was found in Turkey. Also, samples of linen fabrics dating back to the ancient kingdoms of Mesopotamia were found; at that time it was mainly used by the wealthy in society.
The ancient Egyptians loved linen fabrics and used them to wrap mummies. When the mummy of Pharaoh Tutankhamen was discovered in 1922, parts of the linen scrolls that covered his remains were almost completely preserved.
After the Romans invaded Egypt in the 4th century BC, they knew and nurtured linens. In the late Roman era in Egypt, the Egyptians were suppressed by the Romans, and then the Egyptians revolted against them, even the Islamic conquest of Egypt in 1641 AD by Arab leader Amr ibn al-Aas, whom the Egyptians called the savior because he saved them from the persecution of the Romans. At that time the cultivation of flax trees flourished in Egypt as well as the manufacture of linen fabrics.
The linen moved from the Nile Valley to Andalusia through the Islamic conquests of Spain. Linen fabrics then spread in France and Italy and the industry developed to include tablecloths.
In the 17th century, Ireland became known for the finest linen fabrics, and this reputation has continued to this day. The Irish farmers harvest the flax before it reaches maturity. This produces fibers that produce a very fine thread. Because the plant never ripens, it does not produce any seeds that can be used for subsequent crops. So the flax industry in Ireland, to this day, is entirely dependent on the import of flax seeds.
Around 1626, linen was transported to the Netherlands by Irish settlers. Later linen knew his way to North America through colonies as well. The industry of linen fabric developed to include sailcloth, canvas, ropes, and finer linens.
In the 19th century, the invention of textile machinery led to the development of the linen industry and increased production considerably. Linen cloth has also become accessible to all segments of society.
By the beginning of 1950, the production of linen fabrics gradually decreased in both Europe and America due to the emergence of synthetic fibers as well as the lack of government support.
Cross Section of Flax Plant Stem
Micro-structure of Flax Plant Stem
Cuticle and Epidermis:
The cuticle is located at the outer part of the stem. This layer is composed of waxes, cutin, and aromatics. It is a protective barrier for water loss and the attack of microbial pathogens into the inner stem tissue. The cuticle can be easily observed by the oily red spot, which stains the wax in the cuticle with a light red color, thus providing a clear cuticle-specific mark.
Both the epidermis and an adjacent single layer of the thin-walled epidermis are bound together, starting as a single unit.
The cuticle is generally impervious to bacterial attack, but sometimes some disorders and penetration of the cuticle can be occurred by field-retting fungi.
Inner Core Cells:
The core central tissues are the primary xylem and other structural cells. That provides support and water delivery to the flax plant. Core cells are nearly (65% - 75%) of the stem material. The main sugars are glucose, cellulose representative, and xylose, representative of hemicelluloses. Other carbohydrate components are lower in quantities such as pectin.
Lignin chemically is phenolic polymers bound together. It is a class of complex organic polymers that form essential structural materials in plant-supporting tissues.
Nearly all of the lignin in the linen stem is present in the core cells. Positive reactions with chlorine-sulfite for syringyl lignin (dimethoxylated aromatic rings) and acid phloroglucinol for coniferyl lignin (monomethoxylated aromatic rings) indicated the presence of both types of lignin in the core cells. The lignin values for the core cells are about (25% to 30%).
The main function of bast fiber is providing strength to the stem. Bast fibers are long, slim and strong specialized cells grouped in bundles in the cortex area. It is located between the cuticle and epidermis layers. These cellulose-rich cells are the source of flax fibers. These fibers are found in bundles, each with (10-30) fiber cells in the cross-section, completely giving about 600 fiber cells on the stem cross-section. Inside the bundle, individual fiber cells end at different points and are slightly twisted around each other, forming a kind of filament. The length of flax fiber cells ranges from (13 to 60) mm at a rate of (20 to 30) mm.
The value of cellulose in bast fibers ranges from (65% to 80%). Also, bast fibers include pectin, hemicellulose, and aromatic compounds in small amounts. Field-retted fibers showed an increase in glucose (by weight) indicating cellulose, while increases also occurred in Galactose and Mannose. These non-cellular sugars naturally appear to be part of the fiber. Numerous researches have proven the fact that hemicelluloses such as Galactoglucomannan and Xylan are large components in flax fibers. Flax properties, such as high moisture recovery, may be affected by the presence of these non-cellulosic carbohydrates within the cellulosic structure. Proteins and proteoglycans also bind to secondary walls of linen fibers.
Pectin is a complex polysaccharide for many plant cell walls and plant tissue. Pectin is important in maintaining the structure of flax stems, and its degradation reduces the quality of flax fibers.
The percentage of pectin in flax fibers ranges from 20.5% to 34%. The levels of pectin in flax vary greatly and are affected by various factors.
Properties of Flax
1- Physical Properties
- Length: The average length of the flax fibers ranges from 15 to 30 inches. Because of its length, it can be gently woven to hold the ends in. Flax fibers are stronger than cotton because the highly crystalline polymer system of flax allows long polymers to form more hydrogen bonds than cotton. Linen fibers gain strength when wet. This is due to the alignment of the polymer in the amorphous areas of the polymer system in the wet state. Alignment increases the bonds of hydrogen and thus increases the strength of the fibers.
- Color: Flax fiber color is yellowish to grey.
- Heat effect: Flax is good heat resistance due to the polymers along the fibers.
- Elastic-plastic recovery: Linen fibers are hard and inflexible due to the crystal structure of flax fibers. The crystalline structure that gives linen fibers hardness is also the cause of the crease of flax fibers. When polymers break down, linen fibers easily wrinkle.
- Luster: Linen fiber is shiny.
- Absorption: Flax fibers are highly absorbent due to the presence of countless OH groups in polymers. Water can only enter the polymer system in the amorphous areas since the internal polymer distance in crystalline areas is too small for water molecules.
- Sunlight effect: Flax fibers are not affected by sunlight like other natural fibers.
2- Chemical Properties
- Effect of Alkalis: Flax is not affected by alkalis, as there is no attraction between the linen polymers and alkali.
- Effect of Acids: Flax fibers are affected by acids, because of the acid analyses polymer at the glycosidic oxygen atom which binds the two glucose units to form the cellobiose (C12H22O11) unit. The linen polymer consists of a polymerization grade of about 18,000 units of cellulose.
- Effect of Bleaches: sodium hypochlorite (NaClO) and sodium perborate (NaBO3•nH2O) don't affect linen fibers as they are oxidizing bleaches.
- Pigment Ability: Flax fibers can be easily dyed. The most commonly used dyes for dyeing flax are direct, reactive and vat dyes.
- Effect of fungi and bacteria: Moisture and heat increase flax exposure to mold and damage as fungi feed on fibers. Flax fibers are processed by certain chemicals to protect them from mold such as Copper naphthenate.
- Insect Effect: Flax fibers are not affected by mites and beetles.
Manufacture Process of Linen Fibres
It takes about 100 days from planting the seeds to harvesting the flax plant. Flax cannot withstand very hot weather; therefore, in many countries, seed planting is calculated from the time of a year where flax should be harvested due to heat and farmers return to 100 days to set a date for planting. In some regions of the world, linen is grown in winter due to the heat of early spring.
When flax plants are a few inches high, weeds should be carefully removed from the area so as not to disturb sensitive sprouts. Within three months, the plants are straight, and slender stems may reach a height of (61-122) cm with small blue or white fibers.
After about 90 days, the stem turns yellow and the seeds turn brown, indicating that it is time to harvest the plant. The plant should be withdrawn as soon as the brown color appears because any delay produces linen without a precious sheen. It is imperative not to cut the stem in the harvesting process but remove it from the ground intact; if the stem is cut the sap is lost, this affects the quality of the linen. High-quality linens are harvested entirely by hand, grasped directly below the seed heads and gently dragged. These stems are tied into bundles called beets and are ready to extract flax fibers from the stem.
Flax fibers are separated from other parts of the stem by the process of retting to provide the raw material for spinning
The method of water retting produces the best linens. Flax fibers are soaked in water to dissolve pectin and separate the fibers. Swamps and ponds are excellent for this method. The dew dips method is another way to separate flax fibers. In this way, the morning dew helps to separate the flax fibers, and they are pulled as the day warms. Also, flax can be retted by using a chemical process but this process produces lower quality linens.
The retting process must be performed carefully. If the flax is not completely retted, the plant stem cannot be separated from the fibers without injuring the sensitive fibers. Too much retting will weaken the flax fibers.
After the retting process, flax plants are allowed to dry before they undergo a fracture process. In order to crush decomposed stems, they are sent through grooved rollers that dismantle the stem and separate the outer fibers from the bark that will be used to make flax. This process divides the stem into small parts of the bark called shives. After that, the shives are scutched. The scutching machine removes broken shives with rotating paddles, and finally separates flax fibers from the stem.
After that, short fibers, which are used to produce coarser and stronger goods, are separated from longer flax fibers, usually (12-20) cm in length. These fibers produce more luxurious linen fibers.
Long fibers are placed through spreaders machines, which combine fibers of the same length, and place them in a parallel so that the ends overlap, creating a piece of silver. The silver passes through a group of rollers, making the roving (long and narrow bundle of flax fiber) ready for spinning.
Flax roving is placed on a spinning frame, drawn to the thread and eventually wound on spools. Many of these spools are filled on a spinning frame at the same time. The fibers are formed into a continuous strip by pressing between the pulleys and combing them through fine pins.
The atmosphere inside the spinning factory should be humid and warm to make the fibers easier to work into yarn. Wetted linen is woven where roving is run through a bath with hot water in order to bind the fibers together and thus produce thin strands. Dry yarn does not use moisture for spinning, resulting in coarse yarn used to make inexpensive yarn.
The wet threads are transferred from the rollers on the spinning frame to the large drag rollers. They are then transferred to the dryers, and when the yarn is dry, it is wound onto bobbins for weaving or wound into yarn spools of different weights.
The measure of linen yarn is the cut. It is based on (453.59 g) of linen weave to make 300 yards (274.2 m) of yarn equal to one cut.
Uses of Linen Fibers
Linen fibers are used in the manufacture of tablecloths, bath towels, dish towels, bed sheets, wall coverings, upholstery, and window treatments. Also, linen is used to make suits, dresses, skirts, shirts, luggage, canvases, and sewing thread.
How to Care for Linen Fabrics
- Linen fabrics are relatively easy to care for. It has no pilling tendency or lint and can be cleaned dry, steamed or machine washed.
- Linen fabrics are preferably washed separately from other fabrics made of different fibers.
- Linen clothing should be washed at lukewarm temperatures where it will shrink if washed at very hot temperatures.
- It is recommended not to use bleach as it can damage the fabric. Use only a mild washing detergent and be sure to rinse thoroughly from the garment before drying.
- Keep the drying temperature low and remove the clothes while still slightly wet.
- Linen fabrics are easier to iron when wet. Formal linen clothes often require ironing, in order to maintain perfect smoothness.
- Store your linens in a cool, dry place. Flax fibers are not affected by insects such as mites.
Questions & Answers
© 2019 Eman Abdallah Kamel