The textile industry is primarily concerned with the design, production and distribution of yarn, cloth, clothing, garments and dresses. The raw material may be natural, or synthetic using products of the chemical industry.
Artificial fibres can be made by extruding a polymer, through a spinneret into a medium where it hardens. Wet spinning (rayon) uses a coagulating medium. In dry spinning (acetate and triacetate), the polymer is contained in a solvent that evaporates in the heated exit chamber. In melt spinning (nylons and polyesters) the extruded polymer is cooled in gas or air and then sets. All these fibres will be of great length, often kilometres long.
Artificial fibres can be processed as long fibres or batched and cut so they can be processed like a natural fibre.
Natural fibres are either from animals (sheep, goat, rabbit, silk-worm) mineral (asbestos) or from plants (cotton, flax, sisal). These vegetable fibres can come from the seed (cotton), the stem (known as bast fibres: flax, hemp, jute) or the leaf (sisal). Without exception, many processes are needed before a clean even staple is obtained- each with a specific name. With the exception of silk, each of these fibres is short, being only centimeters in length, and each has a rough surface that enables it to bond with similar staples.
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus Gossypium in the mallow family Malvaceae. The fiber is almost pure cellulose. Under natural conditions, the cotton bolls will increase the dispersal of the seeds.
The fiber is most often spun into yarn or thread and used to make a soft, breathable textile. The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric dated to the fifth millennium BC have been found in the Indus Valley Civilization. Although cultivated since antiquity, it was the invention of the cotton gin that lowered the cost of production that led to its widespread use, and it is the most widely used natural fiber cloth in clothing today.
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colors.
Silk is produced by several insects, like silk worms but generally only the silk of moth caterpillars has been used for textile manufacturing. There has been some research into other types of silk, which differ at the molecular level. Silk is mainly produced by the larvae of insects undergoing complete metamorphosis, but some insects such as webspinners and raspy crickets produce silk throughout their lives. Silk production also occurs in Hymenoptera (bees, wasps, and ants), silverfish, mayflies, thrips, leafhoppers, beetles, lacewings, fleas, flies, and midges. Other types of arthropod produce silk, most notably various arachnids such as spiders.
Polyester is a category of polymers that contain the ester functional group in their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in the cutin of plant cuticles, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. The material is used extensively in clothing.
Depending on the chemical structure, polyester can be a thermoplastic or thermoset. There are also polyester resins cured by hardeners; however, the most common polyesters are thermoplastics.
Fabrics woven or knitted from polyester thread or yarn are used extensively in apparel and home furnishings, from shirts and pants to jackets and hats, bed sheets, blankets, upholstered furniture and computer mouse mats. Industrial polyester fibers, yarns and ropes are used in car tire reinforcements, fabrics for conveyor belts, safety belts, coated fabrics and plastic reinforcements with high-energy absorption. Polyester fiber is used as cushioning and insulating material in pillows, comforters and upholstery padding. Polyester fabrics are highly stain-resistant—in fact, the only class of dyes which can be used to alter the color of polyester fabric are what are known as disperse dyes.
Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends (polycotton) can be strong, wrinkle and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less fire resistant and can melt when ignited.
Polyester blends have been renamed so as to suggest their similarity or even superiority to natural fibers (for example, China silk, which is a term in the textiles industry for a 100% polyester fiber woven to resemble the sheen and durability of insect-derived silk).
Polyesters are also used to make bottles, films, tarpaulin, canoes, liquid crystal displays, holograms, filters, dielectric film for capacitors, film insulation for wire and insulating tapes. Polyesters are widely used as a finish on high-quality wood products such as guitars, pianos and vehicle/yacht interiors. Thixotropic properties of spray-applicable polyesters make them ideal for use on open-grain timbers, as they can quickly fill wood grain, with a high-build film thickness per coat. Cured polyesters can be sanded and polished to a high-gloss, durable finish.
Liquid crystalline polyesters are among the first industrially used liquid crystal polymers. They are used for their mechanical properties and heat-resistance. These traits are also important in their application as an abradable seal in jet engines.
Natural polyesters could have a played a significant role in the origins of life. Long heterogeneous polyester chains are known to easily form in a one-pot reaction without catalyst under simple prebiotic conditions.
Velvet is a type of woven tufted fabric in which the cut threads are evenly distributed, with a short dense pile, giving it a distinctive soft feel. By extension, the word velvety means "smooth like velvet." Velvet can be made from either synthetic or natural fibers.
Velvet is woven on a special loom that weaves two thicknesses of the material at the same time. The two pieces are then cut apart to create the pile effect, and the two lengths of fabric are wound on separate take-up rolls. This complicated process meant that velvet was expensive to make before industrial power looms became available, and well-made velvet remains a fairly costly fabric. Velvet is difficult to clean because of its pile, but modern dry cleaning methods make cleaning more feasible. Velvet pile is created by warp or vertical yarns and velveteen pile is created by weft or fill yarns.
Velvet can be made from several different kinds of fibers, traditionally, the most expensive of which is silk. Much of the velvet sold today as "silk velvet" is actually a mix of rayon and silk. Velvet made entirely from silk is rare and usually has market prices of several hundred US dollars per yard. Cotton is also used to make velvet, though this often results in a less luxurious fabric. Velvet can also be made from fibers such as linen, mohair, and wool. A cloth made by the Kuba people of the Democratic Republic of Congo from raffia is often referred to as "Kuba velvet". More recently, synthetic velvets have been developed, mostly from polyester, nylon, viscose, acetate, and from either mixtures of different synthetics or from combined synthetics and natural fibers (for example viscose mixed with silk produces a very soft, reflective fabric). A small percentage of spandex is sometimes added to give the final material a certain amount of stretch (hence "stretch velvet").
Denim is a sturdy cotton warp-faced textile in which the weft passes under two or more warp threads. This twill weaving produces a diagonal ribbing that distinguishes it from cotton duck. While a denim predecessor known as dungaree has been produced in India for hundreds of years, denim itself was first produced in the French city of Nîmes under the name 'serge de Nîmes'.
The most common denim is indigo denim, in which the warp thread is dyed, while the weft thread is left white. As a result of the warp-faced twill weaving, one side of the textile is dominated by the blue warp threads and the other side is dominated by the white weft threads. This causes blue jeans to be white on the inside. The indigo dyeing process, in which the core of the warp threads remains white, creates denim's signature fading characteristics.
How denim is made
All denim goes through generally the same process to creation.
- Cotton is harvested by hand or machine.
- A cotton gin separates the cotton fiber from the seeds.
- The fiber is put into bales. A bale weighs around 550 pounds and can make around 400 pairs of jeans.
- The cotton fiber is then spun into yarn.
- The yarn is dyed giving it color such as the classic denim blue.
- The yarn is then woven in a shuttle loom or projectile loom into denim.
- The denim is then sent to manufacturer for use.
Dry or raw denim (contrasted with "washed denim") is denim that is not washed after having been dyed during production.
Denim fibers from an old pair of jeans through a microscope
Over time dry denim will fade, considered fashionable in some circumstances. During the process of wear, fading will usually occur on those parts of the article that receive the most stress. On a pair of jeans, this includes the upper thighs, the ankles, and the areas behind the knees.
After being made into an article of clothing, most denim articles are washed to make them softer and to reduce or eliminate shrinkage (which could cause the article to not fit properly after its owner washes it). This process is known as sanforization. In addition to being sanforized, "washed denim" is sometimes artificially distressed to produce a "worn" look. Much of the appeal of artificially distressed denim is that it resembles dry denim which has faded. In jeans made from dry denim, such fading is affected by the body of the person who wears them and by the activities of their daily life. This process creates what many enthusiasts feel to be a look more "natural" than artificially distressed denim.
To facilitate the natural distressing process, some wearers of dry denim will abstain from washing their jeans for more than six months. Most dry denim is made with 100% cotton and comes from several different countries. In particular, the United States, Zimbabwe and Japan are popular sources of cotton for making raw denim.
Dry denim also varies in weight, typically measured in by the weight of a yard of denim in ounces. 12 oz. or less is considered light denim, 12 oz. to 16 oz. is considered mid-weight, and over 16 oz. is considered heavyweight. Heavier denim is much more rigid and resistant to wear, but can also take a larger number of wears to break in and feel comfortable.
Natural "honeycomb" fades
Patterns of fading in jeans caused by prolonged periods of wearing them without washing are a way of "personalizing" the garment.
These patterns have specific names:
- combs or honeycombs – meshes of faded line-segments that form behind the knees
- whiskers – faded streaks that form radially from the crotch area
- stacks – irregular bands of fading above the ankle caused by according of the fabric due to contact with the foot or shoe
- train tracks – fading along the out-seams due to abrasion
Denim jeans showing the selvedge of the fabric joined to make a seam
Selvedge (or selvage) is the edge of a fabric as it comes from the loom. Selvedges are woven or knit so that they will not fray, ravel, or curl.
Selvedge denim refers to a unique type of selvedge that is made by passing one continuous cross-yarn (the weft) back and forth through the vertical warp beams. This is traditionally finished at both edges with a contrasting warp (most commonly red); that is why this type of denim is sometimes referred to as "red selvedge." This method of weaving the selvage is possible only when using a shuttle loom.
Shuttle looms weave a narrower 30-inch fabric, which is on average half the width of modern shuttleless Sulzer looms. Consequently, a longer piece of fabric is required to make a pair of jeans from selvedge denim (approximately three yards).
To maximize yield, most jeans are made from wide denim and have a straight outseam that utilizes the full width of the fabric, including the edges. Selvedge denim has come to be associated with premium quality jeans, which show the finished edges from the loom rather than the overlocked edges that are shown on other jeans.
Denim was originally dyed with a dye produced from the plant Indigofera tinctoria, but most denim today is dyed with synthetic indigo dye. In both cases, the yarn undergoes a repeated sequence of dipping and oxidation — the more dips, the stronger the color of the indigo.
Rope dyeing is considered the best yarn-dyeing method, as it eliminates shading across the fabric width. The alternative "slasher process" is cheaper because only one beaming process is needed. In rope dyeing, beaming is done twice.
Denim fabric dyeing is divided into two categories: indigo dyeing and sulfur dyeing. Indigo dyeing produces the traditional blue color or shades similar to it. Sulfur dyeing produces speciality black colors and other colors, such as red, pink, purple, grey, rust, mustard, and green.
- jeans made from red denim
- A mini-skirt made from purple denim
- Jeans made from light grey denim
Stretch denim incorporates an elastic component, such as spandex. This creates a certain amount of "give" in garments made from stretch denim.
Only a small percentage (about 3%) of spandex is required within the fabric to create a significant stretching capacity of about 15%. However, this feature will shorten the wearing life of the garment.
Jute is a long, soft, shiny vegetable fiber that can be spun into coarse, strong threads. It is produced primarily from plants in the genus Corchorus, which was once classified with the family Tiliaceae, and more recently with Malvaceae. The primary source of the fiber is Corchorus olitorius, but it is considered inferior to Corchorus capsularis. "Jute" is the name of the plant or fiber that is used to make burlap, hessian or gunny cloth.
Jute is one of the most affordable natural fibers and it is second only to cotton in amount produced and variety of uses of vegetable fibers. Jute fibers are composed primarily of the plant materials cellulose and lignin. It falls into the bast fiber category (fiber collected from bast, the phloem of the plant, sometimes called the "skin") along with kenaf, industrial hemp, flax (linen), ramie, etc. The industrial term for jute fiber is raw jute. The fibers are off-white to brown, and 1–4 metres (3–13 feet) long. Jute is also called the golden fiber for its color and high cash value.