Other

Textile fibers and threads. Classification

It is a thin, flexible and durable body of considerable length; used for the manufacture of textile products - fabrics, knitwear, non-woven materials, etc. directly or after pre-treatment.

There are textile threads original, primary and secondary. The original textile threads include threads that do not divide in the longitudinal direction without breaking: elementary (chemical, natural, including raw silk, and mineral), monofilament (chemical), as well as narrow strips of paper, film, etc.

Unlike filaments, monofilament directly used for the production of products - thin stockings, nets, etc. To primary textile threads include yarn produced from textile fibers, filament threads consisting of a bundle of (two or more) elementary threads connected by twisting or other means, as well as cut textile threads obtained by twisting strips.

The yarn can be plain, shaped, textured (high volume) and reinforced.

Textile threads are called shaped, the structure of which periodically changes through the formation of thickenings, loops, etc. Textile threads are textile threads whose structure is modified to increase volume or stretchability. Secondary textile threads include twisted threads, usually obtained by twisting several primary ones. Recycled textile threads are also produced textured and shaped.

In addition, textile threads can be homogeneous in composition - from one type of material (for example, cotton yarn, wool, viscose, etc.), mixed - from a mixture of fibers (linen-lavsan yarn, etc.) and heterogeneous (twisted acetate-viscose filament threads). Textile threads obtained by twisting yarn and filament threads are called combined.

A wide variety of textile threads is achieved by using additional operations and processes during their production (for example, singeing, dyeing, bleaching). Textile threads are also used for the manufacture of artificial furs and duplicated materials; Some types of textile threads are used to produce sewing threads, filters for the chemical industry, ropes, etc.

Lit. see under art. Textile fibers. G. N. Kukin
Source: Great Soviet Encyclopedia

Fiber classification

Taking into account classification characteristics, fibers are divided into:

natural

chemical.

TO natural fibers include fibers of natural (plant, animal, mineral) origin: cotton, flax, wool and silk. Chemical fibers are fibers manufactured in factories. In this case, chemical fibers are divided into artificial and synthetic.

Man-made fibers are obtained from natural high molecular weight compounds, which are formed during the development and growth of fibers (cellulose, fibroin, keratin). Fabrics made from artificial fibers include: acetate, viscose, staple, modal. These fabrics are highly breathable, remain dry for a very long time and are pleasant to the touch. Today, all these fabrics are actively used by manufacturers of hosiery products, and, thanks to the latest technologies, they can replace natural ones.

Synthetic fibers are obtained by synthesis from natural low-molecular compounds (phenol, ethylene, acetylene, methane, etc.) as a result of polymerization or polycondensation reactions, mainly from products of oil, coal and natural gases.

Types of threads

Fibers are the basis for the production of filaments, which, depending on the method of joining, are then produced into many other filaments. The following types of threads are distinguished:

single– a thread that does not divide longitudinally without breaking and can be directly used in the production of textiles (often called monofilament). Monofilaments are obtained from synthetic fibers, they usually have a round cross-section, and, depending on the thickness, monofilaments can be used in the production of light, thin fabrics for blouses and heavy ones for interlining materials.

comprehensive- a thread consisting of two or more elementary threads connected to each other by twisting or gluing

twisted- a thread obtained by twisting two or more filament threads, yarn, or both together

yarn- a thread consisting of fibers interconnected by twisting during the spinning process.

Textile fibers are flexible, durable bodies with small transverse dimensions, limited length, suitable for the manufacture of textile products. Textile fibers are divided into two classes: natural and chemical. Based on the origin of the fiber-forming substance, natural fibers are divided into three subclasses: plant, animal and mineral origin, chemical fibers into two subclasses: artificial and synthetic.

Artificial fiber is a chemical fiber made from natural high-molecular substances.

Synthetic fiber is a chemical fiber made from synthetic high molecular weight substances.

Fibers can be elementary or complex.

Elementary - a fiber that does not divide in the longitudinal direction without destruction. Complex fiber consists of longitudinally bonded elementary fibers. Fibers are the starting material for the manufacture of textile products and can be used both in natural and mixed forms. Fiber properties affect process processing them into yarn. Therefore, it is important to know the basic properties of fibers and their characteristics: thickness, length, crimp. The thickness of the products obtained from them depends on the thickness of the fibers and yarn, which affects their consumer properties. Yarn made from thin synthetic fibers is more prone to pilling - the formation of rolled fibers on the surface of the material. The longer the fibers, the more even in thickness and stronger the yarn made from them.

Natural fibers.

Cotton is the fiber that covers the seeds of cotton plants. Cotton is an annual plant 0.6-1.7 m high, growing in areas with a hot climate. The main substance (94-96%) that makes up cotton fiber is cellulose. Under a microscope, cotton fiber of normal maturity looks like a flat ribbon with a corkscrew crimp and a channel filled with air inside. One end of the fiber on the side where it is separated from the cotton seed is open, the other, which has a conical shape, is closed. The amount of fiber depends on its degree of maturity.

Cotton fiber is inherently crimped. Fibers of normal maturity have the greatest crimp - 40-120 crimps per 1 cm. The length of cotton fibers ranges from 1 to 55 mm. Depending on the length of the fibers, cotton is divided into short-staple (20-27 mm), medium-staple (28-34 mm) and long-staple (35-50 mm). Cotton with a length of less than 20 mm is called unspun, i.e. it cannot be made into yarn. There is a certain relationship between the length and thickness of cotton fibers: the longer the fibers, the thinner they are. Therefore, long-staple cotton is also called fine-staple cotton; it has a thickness of 125-167 millitex (mtex). The thickness of medium-staple cotton is 167--220 mtex, short-staple cotton is 220--333 mtex.

The thickness of the fibers is expressed in terms of linear density in hexes. Tex shows how many grams a piece of fiber 1 km long weighs. Millitex = mg/km. The choice of spinning system depends on the length and thickness of the fibers, which in turn affects the quality of the yarn and fabric. Thus, from long-staple cotton, thin, even in thickness, with low hairiness, dense, strong yarn of 5.0 tex and above is obtained, used for the manufacture of high-quality thin and light fabrics: cambric, voile, volte, combed satin, etc. From medium-fiber cotton produce yarn of average and above average linear density of 11.8-84.0 tex, from which the bulk of cotton fabrics are produced: calico, calico, calico, carded satin, corduroy, etc. Short-staple cotton is used to produce loose, thick, uneven in thickness , fluffy yarn, sometimes with foreign impurities - 55-400 tex, used for the production of flannel, paper, flannel, etc.

Cotton fiber has numerous positive properties. It has high hygroscopicity (8-12%), so cotton fabrics have good hygienic properties. The fibers are quite strong. A distinctive feature of cotton fiber is its increased tensile strength in the wet state by 15-17%, which is explained by the doubling of the cross-sectional area of the fiber as a result of its strong swelling in water. Cotton has high heat resistance - fiber destruction does not occur up to 140°C.

Cotton fiber is more resistant to light than viscose and natural silk, but in terms of light resistance it is inferior to bast and wool fibers. Cotton is highly resistant to alkalis, which is used in finishing cotton fabrics (finishing - mercerization, treatment with caustic soda solution). At the same time, the fibers swell greatly, shrink, become uncrimped, smooth, their walls thicken, the channel narrows, strength increases, and shine increases; the fibers are better dyed, holding the dye firmly. Due to its low elasticity, cotton fiber has high creasing, high shrinkage, and low resistance to acid. Cotton is used for the production of fabrics for various purposes, knitwear, non-woven fabrics, curtains, tulle and lace products, sewing threads, braid, laces, ribbons, etc. Cotton fluff is used in the production of medical, clothing, and furniture wool.

Bast fibers are obtained from the stems, leaves or shells of the fruit. various plants. Stem bast fibers are flax, hemp, jute, kenaf, etc., leaf fibers are sisal, etc., fruit fibers are coir, obtained from the covering of coconut shells. Of the bast fibers, flax fibers are the most valuable.

Flax is an annual herbaceous plant, has two varieties: long-lasting flax and curly flax. Fibers are obtained from fiber flax. The main substance that makes up bast fibers is cellulose (about 75%). Associated substances include: lignin, pectin, fatty wax, nitrogenous, coloring, ash substances, water. Flax fiber has four to six edges with pointed ends and characteristic strokes (shifts) in individual areas, resulting from mechanical stress on the fiber during its production.

Unlike cotton, flax fiber has relatively thick walls, a narrow channel, closed at both ends; The surface of the fiber is more even and smooth, so linen fabrics are less likely to get dirty than cotton fabrics and are easier to wash. These properties of flax are especially valuable for linen fabrics. Flax fiber is also unique in that, with high hygroscopicity (12%), it absorbs and releases moisture faster than other textile fibers; it is stronger than cotton, elongation at break is 2-3%. The content of lignin in flax fiber makes it resistant to light, weather, and microorganisms. Thermal destruction of the fiber does not occur up to + 160°C. Chemical properties flax fiber is similar to cotton, i.e. it is resistant to alkalis, but not resistant to acids. Due to the fact that linen fabrics have their natural, quite beautiful silky shine, they are not subjected to mercerization. However, flax fiber is highly wrinkled due to low elasticity and is difficult to bleach and dye.

Due to its high hygienic and strength properties, flax fibers are used to produce linen fabrics (for underwear, table linen, bed linen), and summer suit and dress fabrics. At the same time, about half of linen fabrics are produced in a mixture with other fibers, a significant part of which is semi-linen underwear fabrics with cotton yarn at the base. Canvas, fire hoses, cords, shoe threads are also made from flax fibers, and coarser fabrics are made from flax tow: sack fabrics, canvas, tarpaulins, sailcloths, etc.

Hemp is obtained from the annual hemp plant. The fibers are used to produce ropes, ropes, twines, packaging and bagging fabrics.

Kenaf, jute is obtained from annual plants of the mallow and linden families. Kenaf and jute are used to produce bag and container fabrics; used for transporting and storing moisture-intensive goods.

Wool is a fiber from the removed hair of sheep, goats, camels, rabbits and other animals. Wool removed by shearing in the form of a single hairline is called fleece. Wool fibers are composed of the protein keratin, which, like other proteins, contains amino acids.

Under a microscope, wool fibers can be easily distinguished from other fibers - their outer surface is covered with scales. The scaly layer consists of small plates in the form of cone-shaped rings, strung on top of each other, and represents keratinized cells. The scaly layer is followed by the cortical layer - the main one, on which the properties of the fiber and products made from them depend. The fiber may also have a third layer - a core layer, consisting of loose, air-filled cells. Under a microscope, the peculiar crimp of the wool fibers is also visible. Depending on what layers are present in the wool, it can be of the following types: fluff, transitional hair, awn, dead hair.

Down is a thin, highly crimped, silky fiber without a core layer. Transitional hair has an intermittent, loose core layer, due to which it is uneven in thickness, strength, and has less crimp. The awn and dead hair have a large core layer and are characterized by great thickness, lack of crimp, increased rigidity and fragility, and low strength. Depending on the thickness of the fibers and the uniformity of the composition, wool is divided into fine, semi-fine, semi-coarse and coarse. Important indicators of the quality of wool fiber are its length and thickness. The length of wool affects the technology for obtaining yarn, its quality and the quality of finished products. From long fibers (55-120 mm) combed (worsted) yarn is obtained - thin, even in thickness, dense, smooth. From short fibers (up to 55 mm), hardware (cloth) yarn is obtained, which, unlike worsted, is thicker, loose, fluffy, with uneven thickness. The properties of wool are unique in their own way - it is characterized by high feltability, which is explained by the presence of a scaly layer on the surface of the fiber.

Thanks to this property, felt, cloth fabrics, felt, blankets, and felted shoes are made from wool. Wool has high heat-protective properties and is highly elastic. Alkalies have a destructive effect on wool; it is resistant to acids. Therefore, if wool fibers containing plant impurities are treated with an acid solution, then these impurities dissolve, and the wool fibers remain pure. This process of cleaning wool is called carbonization. The hygroscopicity of wool is high (15-17%), but unlike other fibers it slowly absorbs and releases moisture, remaining dry to the touch. In water it swells greatly, and the cross-sectional area increases by 30-35%. Moistened fiber in a stretched state can be fixed by drying; when re-moistened, the length of the fiber is restored again. This property of wool is taken into account during the wet-heat treatment of garments made from woolen fabrics for stretching and stretching their individual parts.

Wool is a fairly strong fiber with a high elongation at break; when wet, fibers lose 30% strength. The disadvantage of wool is its low heat resistance - at temperatures of 100-110°C, the fibers become brittle, stiff, and their strength decreases. From fine and semi-fine wool, both in pure form and mixed with other fibers (cotton, viscose, nylon, lavsan, nitron), worsted and fine cloth dress, suit, coat fabrics, non-woven fabrics, knitwear, scarves, blankets are produced. ; from semi-rough and coarse - coarse cloth coat fabrics, felted shoes, felt.

Goat down is used mainly for the production of scarves, knitwear and some dress, suit, and coat fabrics; camel wool - for the production of blankets and national products. Lower-quality fabrics, felted shoes, non-woven materials, and construction felt are produced from recovered wool.

Natural silk, in terms of its properties and cost, is the most valuable textile raw material. It is obtained by unwinding cocoons formed by silkworm caterpillars. The most widespread and valuable silk is the silkworm, which accounts for 90% of world silk production.

The homeland of silk is China, where the silkworm was cultivated 3000 BC. e. The production of silk goes through the following stages: the silkworm butterfly lays eggs (grena), from which caterpillars hatch about 3 mm long. They feed on mulberry leaves, hence the name silkworm. After a month, the caterpillar, having accumulated natural silk, through the silk-secreting glands located on both sides of the body, wraps itself in a continuous thread of 40-45 layers and forms a cocoon. Cocoon winding lasts 3-4 days. Inside the cocoon, the caterpillar turns into a butterfly, which, having made a hole in the cocoon with an alkaline liquid, comes out of it. Such a cocoon is unsuitable for further unwinding. Cocoon threads are very thin, so they are unwound simultaneously from several cocoons (6-8), connecting them into one complex thread. This thread is called raw silk. The total length of the unwinding thread is on average 1000-1300 m.

The scrap remaining after unwinding the cocoon (a thin shell that cannot be unwinded, containing about 20% of the length of the thread), rejected cocoons are processed into short fibers, from which silk yarn is obtained. Of all natural fibers, natural silk is the lightest fiber and, along with the beautiful appearance has high hygroscopicity (11%), softness, silkiness, low creasing. Natural silk has high strength. The breaking load of silk when wet is reduced by approximately 15%. Natural silk is resistant to acids, but not to alkalis, has low light fastness, relatively low heat resistance (100-110 ° C) and high shrinkage. Silk is used to make dress and blouse fabrics, as well as sewing threads, ribbons, and laces. Chemical fibers are obtained by chemical processing of natural (cellulose, proteins, etc.) or synthetic high-molecular substances (polyamides, polyesters).

The technological process of manufacturing chemical fibers consists of three main stages - obtaining a spinning solution, forming fibers from it and finishing the fibers. The resulting spinning solution enters the spinnerets - metal caps with small holes - and flows out of them in the form of continuous streams, which harden in a dry or wet way (air or water) and turn into filaments. The shape of the holes of the spinnerets is usually round, and to obtain profiled threads, spinnerets with holes in the form of a triangle, polyhedron, asterisks, etc. are used.

When producing short fibers, spinnerets with a large number of holes are used. Elementary threads from many spinnerets are combined into one bundle and cut into fibers of the required length, which corresponds to the length of natural fibers. The formed fibers are subjected to finishing. Depending on the type of finish, the fibers are white, dyed, shiny or matted.

Artificial fibers.

Artificial fibers are obtained from natural high-molecular compounds - cellulose, proteins, metals, their alloys, silicate glasses. The most common artificial fiber is viscose, produced from cellulose. For the production of viscose fiber, wood pulp, mainly spruce pulp, is usually used. The wood is split, treated with chemicals, and turned into a spinning solution - viscose. Viscose fibers are produced in the form of complex threads and fibres, their application varies. Viscose fiber is hygienic, has high hygroscopicity (11-12%), products made from viscose absorb moisture well; it is resistant to alkalis; The heat resistance of viscose fiber is high.

But viscose fiber has disadvantages:

-- due to low elasticity, it wrinkles greatly;
-- high fiber shrinkage (6--8%);
-- when wet, it loses strength (up to 50-60%). It is not recommended to rub or twist the products.

Other artificial fibers used include acetate and triacetate fibers. Metal-containing fibers (threads) can be metallic or metallized (film with a metal coating). Metal threads are monofilaments of round or flat cross-section made from aluminum foil, copper and its alloys, silver, gold and other metals. Alunit (Lurex) is a metal thread made of aluminum foil, coated on both sides with a protective antioxidant film.

Synthetic fibers.

Synthetic fibers are obtained from natural, low-molecular substances (monomers), which are converted into high-molecular substances (polymers) through chemical synthesis. Polyamide (nylon) fibers are obtained from caprolactam polymer, a low-molecular crystalline substance produced from coal or oil. In other countries, nylon fibers are called differently: in the USA, England - nylon, in Germany - dederon. Polyester fibers (lavsan) are produced under various names: in England and Canada - terylene, in the USA - dacron, in Japan - polyester. The presence of valuable consumer properties of polyester fibers has determined their wide application in textile, knitting production, in the production of artificial fur.

Polyacrylonitrile fibers (acrylic, nitron): in the USA - orlon, in England - kurtel, in Japan - cashmilon. Nitron fiber resembles wool in its properties and appearance. Fibers in their pure form and mixed with wool are used to produce dress and suit fabrics, artificial fur, various knitwear, and curtains and tulle products.

Polyvinyl chloride (PVC), chlorine fiber is produced from a solution of polyvinyl chloride resin in dimethylformamide (PVC) and from chlorinated polyvinyl chloride. These fibers differ significantly from other synthetic fibers: as a result of their low thermal conductivity, they have a high thermal insulation ability, do not burn, do not rot, and are very resistant to chemical influences.

Polyurethane fibers. By processing polyurethane resin, spandex or lycra fiber is obtained, produced in the form of monofilament. Different high elasticity, its elongation is up to 800%. It is used instead of rubber core in the production of women's toiletries and high-stretch knitwear.

Alunit is metal threads made of aluminum foil, coated with a polymer film that protects the metal from oxidation. To strengthen it, alunit is twisted with nylon threads.

Hardware cotton yarn is a fluffy, loose, thick yarn obtained from short fibers, characterized by low strength.

Hardware wool yarn is produced using a machine system from short-fiber wool and waste (spinning waste) with a thickness of 42-500 tex, loose, fluffy, uneven in thickness and strength.

Reinforced thread is a textile thread that has a complex structure consisting of a braided core, i.e. the axial thread is wrapped or tightly braided with fibers or other threads.

Asbestos fiber is a mineral fiber found in rocks. The longest fibers (10 mm or more) are processed into yarn, used for the production of technical fabrics, tapes, cords, used mainly for thermal insulation.

Acetate fiber is an artificial fiber produced from solutions of partially saponified secondary cellulose acetate in acetate using a dry method (pressing through a spinneret and drying).

Viscose fiber is an artificial fiber produced from wood cellulose, converted by chemical transformations into a viscous liquid (viscose), which is pressed through spinnerets and reduced to cellulose hydrate.

Recovered (regenerated) wool is an additional source of raw materials for light industry. It is obtained from scraps of yarn during spinning and weaving, from scraps of woolen fabrics and knitwear in sewing production, and from waste raw materials (used fabrics and knitwear). Used in small quantities(20-35%) mixed with regular wool and with the addition of 10-30% synthetic fiber to reduce production costs.

High volume yarn is a yarn whose additional volume is obtained by chemical and/or heat treatment.

Combed cotton yarn is a thin, smooth, even thickness yarn obtained from long-staple cotton, characterized by the greatest strength.

Combed (worsted) wool yarn is thin, smooth, produced from long-staple wool fiber using a combed spinning system, with a thickness of 15.5-42 tex.

Coarse wool is heterogeneous wool consisting mainly of guard hairs with a thickness of 41 microns or more. Obtained by shearing sheep of coarse-wool breeds (Caucasian, Tushino, etc.).

Jute, kenaf are fibers obtained from the stems of plants of the same names, reaching a height of 3 m or more. Dry stems contain up to 21% fiber, used for technical, packaging, furniture fabrics and carpets. The largest sown areas are in India and Bangladesh.

Crimped fiber is a natural or chemical fiber that has crimp.

Man-made fiber (thread) is a chemical fiber (thread) made as a result of a production process from natural polymers through chemical processing.

Carded cotton yarn is a thick, uneven yarn obtained from medium length cotton. Used for the production of cotton fabrics.

Combined thread is a textile thread consisting of complex threads or monofilaments, or complex threads that differ in chemical composition or structure, different in fibrous composition and structure.

Complex thread is a textile thread consisting of two or more longitudinally connected and twisted elementary fibers.

Crepe thread is characterized by high (crepe) twist. To obtain natural silk crepe, 2-5 threads of raw silk are twisted to 2200-3200 kr/m, and then they are steamed to fix the twist. Crepe from complex chemical threads is obtained by twisting one thread up to 1500-200 cr/m. Due to the high twist, fabrics made from crepe threads are characterized by significant elasticity, rigidity, and roughness.

Twisted thread is a textile thread twisted from one or more textile threads.

Twisted yarn is a textile thread twisted from two or more yarns.

Flax is a bast fiber obtained from the stems of a plant of the same name. Fiber flax with a long (up to 1 m) and thin (1-2 mm in diameter) stem is cultivated for fiber.

Bast fiber is long prosenchymal cells in the stems of various plants, devoid of part of the contents of the plant stem. Fibers from bast crops (flax, nettle, hemp, etc.) are used to produce yarn.

Wet-spun linen yarn is produced with a thickness of 24-200 tex from long fiber and tow, while the roving (a semi-finished flax product) is thin and uniform in thickness and is wetted before spinning.

Dry-spun linen yarn is produced from flax fiber and tow, uneven in thickness, 33-666 tex.

Lurex is a thread in the form of a shiny narrow metal strip covered with foil or a metallized film.

Copper-ammonia fiber is produced from a solution of cellulose in a copper-ammonia complex, with properties close to viscose. Production is limited, as it is associated with significant copper consumption (50 g per 1 kg of fiber).

Multi-twist thread is a twisted thread of two or more textile threads, one of which is single-twist, twisted together in one or more twisting operations.

Modified thread (fiber) is a textile thread (fiber) with specified specific properties, obtained by additional chemical or physical modification.

Mooskrep is a double twist thread. Mooskrepe made from natural silk is produced by twisting a crepe thread with 2-3 threads of raw silk. Mooscrep from artificial threads is obtained by caning and subsequent twisting of crepe thread and flat twist thread. The second twist is made in the direction of the crepe thread at approximately 200 cr/m. The crepe thread is a core thread, and a raw silk thread or a flat twist thread is a surge thread that wraps around the core thread.

Muslin -- thin thread medium twist. Natural silk muslin is produced by twisting one thread of raw silk up to 1500-1800 cr/m, followed by steaming to fix the twist. Muslin from a complex chemical thread (viscose, acetate, nylon) is produced by twisting the thread up to 600-800 cr/m.

Maron (nylon), melan (lavsan) are tensile threads, obtained, like high-tensile threads, by chemical treatment, but with additional heat treatment with some stretching. As a result of this, the spiral-shaped tortuosity characteristic of elastic turns into a sinusoidal one and is fixed in this state. The threads are soft, fluffy, elongation 30-50%.

Natural fiber is a textile fiber of natural origin.

Natural silk is a product of the secretion of the silk glands of silkworm caterpillars - the protein substance fibroin - in the form of a thin continuous thread curled into a cocoon. At the moment the cocoon is formed, the caterpillars secrete two thin silks, which harden when exposed to air. At the same time, the protein substance sericin is released, which glues the mulberries together.

Heterogeneous thread is a textile thread consisting of fibers of different nature.

A single thread is an untwisted, untwisted thread or an untwisted twisted thread that has received a twist in one twisting operation.

Single Twist Thread - A twisted thread made from two or more single strands twisted together in a single twisting operation.

Homogeneous thread is a textile thread consisting of textile fibers of the same nature.

Homogeneous yarn is a yarn consisting of fibers of the same type.

Hemp - produced from annual tall plant hemp. Hemp is divided into filament hemp (thin), used for making yarn, industrial hemp (thick, coarse), from which technical fabrics are produced, and rope hemp - for ropes.

Overtrace yarn is yarn with alternating thickening and thinning.

Film textile thread is a flat filament thread obtained by splitting a textile film or extruding in the form of a strip.

Polyacrylonitrile fiber (nitron) is a synthetic fiber formed from solutions of polyacrylonitrile or copolymers containing more than 85% (by weight) acrylonitrile using a wet or dry method. Produced under the following trade names: orlon, acrylon (USA), cashmilon (Japan), dralon (Germany), etc.

Polyamide fiber is a synthetic fiber formed from polyamide melts. It is made from polycaprolactam under the following trade names: nylon (Russia), nylon (Japan), perlon, dederon (Germany), amelan (Japan), etc.

Polyvinyl alcohol fiber is a synthetic fiber formed from solutions of polyvinyl alcohol, produced in many countries under the following names: vinol (Russia), vinylon, kuralon (Japan), vinalon (DPRK), etc.

Polyvinyl chloride fiber is a synthetic fiber formed from solutions of polyvinyl chloride, perchlorovinyl resin or vinyl chloride copolymers using a dry or wet method; is produced in the form of continuous threads or staple fibers under the following trade names: chlorin, saran, vignon (USA), roville (France), Teviron (Japan), etc.

Polynose fiber is a type of viscose fiber with a high degree of orientation of macromolecules in the structure and homogeneity of the structure in the cross section, as a result of which it has high strength and low elongation.

Polypropylene fiber is a synthetic fiber formed from a melt of polypropylene. Due to its low density, it is used for the manufacture of non-sinking ropes, nets, filter and upholstery materials; staple polypropylene fibers - for the production of blankets, fabrics, outerwear. Textured (high volume) polypropylene fibers are used primarily in carpet production. They are produced under various trade names: Herculon (USA), Ulstrene (UK), Found (Japan), Mercalone (Italy), etc.

Polyester fiber (lavsan) is a synthetic fiber formed from a melt of polyethylene terephthalate (synthesis of petroleum distillation products). Technical thread made from polyester fibers is used in the manufacture of conveyor belts, drive belts, ropes, sails, etc. Monofilament is used to make nets for paper-making machines, strings for rackets, etc. High-volume thread is obtained using the “false twist” method.

Semi-coarse wool - consists of transitional hair fibers and relatively thin awn fibers with a thickness of 35-40 microns. It is obtained from fine-fleece-coarse-wool sheep (Zadonsky, steppe, Volga, etc.).

Semi-fine wool is a homogeneous wool consisting of coarse fibers, 25-35 microns thick, classified as fluff or transitional hair. Obtained by shearing semi-fine fleece sheep (precut, Kazakh, Kuibyshev, etc.).

Yarn is a textile thread consisting of fibers of limited length (natural or staple chemical), connected into a long thread by spinning (orientation and twisting of the fibers).

Nepsed yarn is yarn with spun inclusions of fibers of a different color or type.

Ramie is a fiber produced from perennial grasses and shrubs of the nettle family, containing up to 21% of durable silky fiber in dry stems.

Fleece is a continuous layer obtained by shearing sheep, consisting of tufts of wool firmly held next to each other - staples.

Siblon is a modified durable viscose fiber with uniform properties, both external and inner layers, achieved by regenerating cellulose at low temperatures of the precipitation bath and flowing out the fiber at high temperatures (95 ° C).

Synthetic fiber (thread) is a chemical fiber (thread) made from synthetic fiber-forming polymers (polyamide, polyester, etc.).

Blended yarn is a yarn consisting of two or more types of fibers.

Spandex is a polyurethane monofilament with high elongation - up to 700-800%.

Glass filaments are filaments obtained by pressing molten glass mass through thin holes. The flowing streams, cooling, turn into flexible threads. The main application is heat and electrical insulation, filters.

Raw yarn is gray-yellow yarn without any finishing.

Textile tape (roving) is a set of longitudinally oriented staple fibers of a given linear density without twist, intended for subsequent machining(pulling, twisting).

Textile monofilament thread (monofilament thread) is an elementary thread used for the direct manufacture of textile products.

Textile thread is a textile product of unlimited length and relatively small cross-section, consisting of textile fibers and/or filaments, with or without twist.

Textile fiber is a thin, flexible, extended body of limited length, suitable for making yarn and threads.

Textured thread is a crimped textile thread, the structure of which, through additional processing, has an increased specific volume and elongation.

Heat-fixed thread (fiber) is a textile thread (fiber) subjected to heat or thermal moisture treatment in order to bring its structure to an equilibrium state.

Fine wool is a homogeneous wool consisting only of fluff fibers, up to 25 microns thick, with fine uniform crimp, soft, elastic, of the same length. It is obtained from fine-wool sheep (Merino, Tsigai) and is used for high-quality fabrics and knitwear.

Triacetate fiber is obtained from solutions of triacetyl cellulose in a mixture of methylene chloride and alcohol using a dry method.

Spun thread is a textile thread consisting of two or more threads joined without twisting.

Shaped thread is a textile thread that has periodically repeating local changes in structure in the form of knots, loops and coloring.

Fibrillated film thread is a film textile thread with longitudinal cuts, having transverse connections between fibrils. Fibrils in this case are structural elements with a fineness of the same order as that of textile fibers.

Chemical fiber (thread) is a textile fiber (thread) obtained as a result of a production process from artificial, synthetic polymers or inorganic substances.

Cotton is the fiber from the surface of the seeds of the cotton plant, an annual shrub that grows in warm climates. There are long-staple cotton (34-50 mm), medium-staple (24-35 mm) and short-staple (up to 27 mm).

Raw cotton is the raw material of cotton gins; it contains a large amount of cotton seeds, covered with cotton fiber, with admixtures of leaves, parts of bolls, etc.

Silk yarn is made from natural silk waste (scraping off defective cocoons), which is cleaned of impurities, boiled and split into individual fibers (up to 7 tex).

Warp silk is a double twist thread of 2-4 strands of raw silk. First, threads of raw silk are twisted to the left at 400-600 cr/m, and then 2-3 such threads are caned and twisted to the right at 480-600 cr/m. With secondary reverse twist, the primary twist is slightly reduced, resulting in a soft twisted thread.

Raw silk is the product of unwinding cocoons on special cocoon winding machines, where several (4-9) threads folded together are wound on a reel.

Weft silk is a flat twist thread obtained by twisting 2-5 or more threads of raw silk with a flat twist (125 twists per 1 m). The thread is soft, even, smooth, 9.1-7.1 tex thick.

Wool is the hair fiber of various animals: sheep, goats, camels, etc.

Staple fiber is an elementary fiber of limited length, which is obtained by cutting a tow of chemical fibers.

Staple fiber in mass is a disordered mass of elementary fibers of limited length.

Elastic - (from the Greek Elastos - flexible, viscous) highly tensile textured threads with high (up to 40%) elongation, spiral crimp and fluffiness. It is produced on “false torsion” machines by imparting a twist of 2500-3000 kr/m to the thread and then removing the resulting internal stresses in a heat chamber (150-180 °C). As a result, the thread takes the shape of a spiral. Elastic is used to make hosiery.

Elementary thread (filament) is a single textile thread of practically unlimited length, considered as endless.

Elemental fiber is a textile fiber that is a single, indivisible element.

Natural fibers, depending on their chemical composition, are divided into two subclasses: organic (plant and animal origin) and mineral fibers of plant origin: cotton, flax, hemp, jute, kenaf, kendyr, ramie, rope, sisal, etc.

Fibers of animal origin: wool of sheep, goats, camels and other animals, natural silk of mulberry and oak silkworms. Asbestos is a mineral fiber.

Chemical fibers are divided into two subclasses: artificial and synthetic. Artificial fibers are divided into organic (viscose fiber, acetate, triacetate, copper-ammonia, mtilon B, siblon, polynose, etc.) and inorganic (glass and metal fibers and threads). Synthetic fibers, depending on the nature of the starting materials, are divided into polyamide (nylon, anide, enanth), polyester (lavsan), polyacrylonitrile (nitron), polyolefin (polypropylene, polyethylene), polyurethane (spandex), polyvinyl alcohol (vinol), polyvinyl chloride (chlorine) , fluorine-containing (fluorlon), as well as polyformaldehyde, polybutylene terephthalate, etc.

Artificial fibers.

Viscose fiber is the most natural of all chemical fibers, obtained from natural cellulose. Depending on the purpose, viscose fibers are produced in the form of threads, as well as staple (short) fibers with a shiny or matte surface. The fiber has good hygroscopicity (35-40%), light resistance and softness. The disadvantages of viscose fibers are: a large loss of strength when wet, easy creasing, insufficient resistance to friction and significant shrinkage when moistened. These disadvantages are eliminated in modified viscose fibers (polinose, siblon, mtilon), which are characterized by significantly higher dry and wet strength, greater wear resistance, less shrinkage and increased crease resistance.

Siblon, compared to conventional viscose fiber, has a lower degree of shrinkage, increased crease resistance, wet strength and alkali resistance. Mtilan has antimicrobial properties and is used in medicine as threads for temporary fastening of surgical sutures. Viscose fibers are used in the production of clothing fabrics, underwear and outerwear, both in pure form and in mixtures with other fibers and threads.

Acetate and triacetate fibers are obtained from cotton pulp. Fabrics made from acetate fibers are very similar in appearance to natural silk, have high elasticity, softness, good drape, low creasing, and the ability to transmit ultraviolet rays.

Hygroscopicity is less than that of viscose, so they become electrified. Fabrics made from triacetate fiber have low creasing and shrinkage, but lose strength when wet. Due to their high elasticity, the fabrics retain their shape and finishes (corrugated and pleated) well. High heat resistance allows you to iron fabrics made of acetate and triacetate fibers at 150-160°C.

Monofilament is a single-strand thread that does not divide in the longitudinal direction without destruction, suitable for direct use in textiles.

A filament thread consists of two or more elementary threads joined together by twisting or gluing. A filament is a single thread that is integral part complex thread or tow. The filament cannot be used as a monofilament.

Yarn is a thread consisting of fibers connected by twisting or gluing.

Twisted thread is a thread twisted from two or more filament threads, yarns, or both.

Shaped thread - a thread that has periodically repeating local changes in structure (nodules, loops, thickenings, etc.) and color.

Reinforced thread is a special type of non-uniform threads obtained by wrapping a core component with forced threads or fibers.

Textured thread is a thread whose structure has been modified by additional processing to increase specific volume or elongation.

Based on the type of raw material used, yarn is divided into homogeneous and mixed, and threads into homogeneous and heterogeneous. Homogeneous threads and yarn consist of fibers of the same type of raw material, mixed yarn - from a mixture of fibers of different types of raw materials, heterogeneous thread - from threads of different types of raw materials.

Threads and yarn are made from natural and chemical (artificial and synthetic) fibers. Natural fiber is of natural origin (plant, animal, mineral). Chemical fibers are made from natural or synthetic high molecular weight substances. These include artificial fibers obtained from natural high-molecular substances. Synthetic fibers are made from synthetic high molecular weight substances.

Cotton, linen, wool yarn and natural silk are produced from natural fibers.

Cotton yarn is produced in gray, dyed and melange (obtained from dyed cotton).

Linen yarn is produced using a wet and dry spinning system. Yarn made from flax fiber, depending on the finishing method, can be raw, boiled, bleached and dyed.

Wool yarn is produced using combed and machine spinning systems. Depending on the linear density of the wool fiber, combed yarn is divided into fine-combed, coarse-combed and semi-combed, and hardware yarn is divided into fine-woven and coarse-woven. A significant portion of wool yarn is double-twisted.

Natural silk is obtained by unwinding the cocoons of mulberry and oak silkworms in the form of complexly glued threads (raw silk). In addition, they produce twisted natural silk with different number twists: with regular twist - up to 600 twist/m and crepe twist - up to 3200 twist/m. Silk yarn is made from waste obtained from processing natural silk.

Man-made fibers include viscose, acetate, triacetate and copper-ammonia. Artificial fibers are also used in pure form and mixed with natural ones.

Synthetic fibers, depending on the chemical structure, are divided into several types: polyamide (nylon, anide, enanth), polyester (lavsan), polyacrylonitrile (nitrone), polyolefin (polypropylene, polyethylene), etc., from which threads and staple fiber are made to produce homogeneous and mixed yarn. Threads made from synthetic fibers have increased strength, resistance to abrasion and repeated loads.

Polyamide and polyester fibers, which have low thermoplasticity, are more often than other fibers used to make textured threads, which are characterized by increased bulk, fluffiness and softness. The structure of textured threads is changed mechanically (twisting, pressing, crimping, knitting) and fixed by heat treatment. Textured threads include: elastic (spirally crimped), corrugated (flat crimped), ajilon (spatially crimped), taslan (looped), as well as melan, maron, etc.

For the production of textile materials, yarn, filament threads and monofilament threads are used.

Yarn called a thread (GOST 13784-94), consisting of fibers of limited length (staple), connected by twisting. Complex thread(multifilament) consists of two or more elementary filaments. Monofilament(monofilament thread) is a filament thread suitable for direct use in textiles. Yarn is formed from fiber mass during the spinning process. There are three main methods of spinning: carded, combed and machine.

Carded yarn (carded yarn) is the most common. It is made from medium-fiber cotton and chemical fibers. The carded spinning process consists of the operations of opening and fraying, carding, leveling and drawing, pre-spinning and spinning. Cotton arrives at the factory in bales. The compressed fibrous mass is loosened here in special loosening-scraping units into small shreds and cleaned of large impurities. Small impurities and dust are removed by mesh drums, to which the cotton is sucked by air draft. On carding machines, cotton scraps are combed using needle-shaped (carded) surfaces. The combed cotton is formed into a rope called sliver. The tapes are transferred to the draw frames. To equalize the thickness of the ribbons, as well as when producing mixed yarn from cotton and chemical fibers, several ribbons are combined into one. In the drawing apparatus, the resulting tape is thinned, the fibers are straightened and oriented along the tape. During the pre-spinning process on roving machines, the slivers are stretched and become thinner. To fasten the fibers together, they are slightly twisted, and a roving is formed. During final spinning on ring spinning machines, the roving is thinned by a drafting apparatus to the required linear density and, twisted into yarn, is wound in the shape of a cob on a cartridge mounted on a spindle. Carded yarn from ring spinning machines consists of relatively straightened and oriented fibers . Each fiber does not lie in one layer of yarn, but moves from the center to the periphery and back, located along helical lines of variable pitch and radius. The areas of fibers located in the outer layers of the yarn are more stressed than the areas in the center, which creates an imbalance in the structure of the yarn.

Spindleless machines are widespread rotor spinning. Such machines operate on the principle of mechanical and aerodynamic influence on the fibers. Rotor-spun yarn differs in structure from ring-spun yarn. The density of the fibers in the cross-section of such yarn is not the same: the high density of the central layer (core), in which the fibers are compressed by twist, decreases towards the outer layers. Uneven distribution of fibers in the yarn leads to a decrease in its strength.

Combed yarn (combed yarn) It is produced from long-fiber cotton, flax, long thin semi-coarse and coarse wool, as well as from waste from sericulture, cocoon reeling, silk spinning and silk weaving. Through the combed spinning system, the fibers pass the most long way. After scuffing and carding, the fibers are prepared for combing, followed by the combing process itself and again leveling and drawing, pre-spinning and spinning. The purpose of combing for all fibers is the same: to remove short fibers from the fiber mass, straighten and orient long ones. Combed yarn has the most regular structure. Fibers, carefully combed, evenly distributed along the length and cross-section, form a dense thread, uniform in thickness, less fleecy than carded. Since the fibers in combed yarn are longer than in carded yarn, the degree of their fastening is correspondingly greater. Therefore, the strength of combed yarn is higher than carded yarn of the same origin.

Hardware spun yarn (hardware yarn) produced from short-staple cotton, wool and chemical fibers added to them, as well as spinning waste and regenerated fibers (turned into fiber from flaps). Mixing fibers of different types is widespread in machine spinning. The hardware spinning process is the shortest. After loosening, the fibrous mass goes to carding, which is carried out on two or three carding machines connected in series. On the last carding machine, the web is divided into strips, which are rolled (knitted) into roving. Yarn is formed from the roving on spinning machines. Hardware yarn is the least uniform in thickness; the fibers in it are almost not straightened and are not oriented enough. Loose, weakly twisted hardware yarn gives products made from it good heat-shielding properties.

According to the fiber composition, the yarn can be homogeneous and mixed. Homogeneous yarn consists of fibers of the same nature (cotton, wool, linen, chemicals of the same type), mixed yarn - from a mixture of fibers of different natures. When connecting fibers of different types, they are selected in such a way that the negative qualities of one fiber are compensated by the positive qualities of the other.

Yarn is classified according to its structure single-strand, caned and twisted.

Spun yarn consists of two or more strands folded lengthwise and not twisted together. Spun yarn is widely used in knitting production. Single-strand yarn is produced on spinning machines by right- and left-hand twisting of elementary fibers. When the spindle or spinning chamber rotates clockwise, right-twist yarn Z is formed (Fig. 1a), when rotated counterclockwise, left-twist yarn S is formed (Fig. 1, b).

Twisted yarn is produced on twisting machines and, according to the method of twisting, is divided into single-twist, multi-twist, shaped, reinforced, textured And combined.

Single twist yarn obtained by twisting two or more threads of the same length. It has a smooth surface. Single twist yarns are often not balanced enough in twist. When unwinding from the package, it can form twists and loops. Twist-balanced yarn is obtained by alternating the directions of spinning and final twists (Z/S or S/Z) at a certain ratio of their values. During the final twist in the direction opposite to the spinning direction, the component threads are untwisted until they are secured by turns of re-twist. Due to this, when combined, they form a dense, rounded thread, evenly filled with fibers. Arranged in spiral turns, the constituent threads bend around each other, as a result of which the fibers acquire additional strength, the yarn acquires greater strength, and products made from it acquire greater wear resistance.

Multi-twist yarn is obtained as a result of two or more successive torsion processes. Most often, two single-twist threads are connected by twisting them in the direction opposite to the direction of the pre-twist.

Fancy yarn (fancy yarn) consists of a core thread, which is wrapped around a surge (effective) thread of greater length than the core. The surge thread can form evenly spaced spirals along the length of the core thread (Fig. 3a). The spiral effect can also be obtained by twisting a roving with a linear density of about 1000 tex with single-strand yarn with a linear density of 25...30 tex (Fig. 3, b). The intermittent effect is formed in knotted yarn (Fig. 3, c) with dense, evenly distributed round or oblong single-color or multi-color (with several threads) knots and in pongee yarn (Fig. 3, d) with uneven loose knots. Fancy yarn from fibers of all types is widely used in the production of dress, suit, coat fabrics and knitted fabrics. It allows you to produce spectacular materials.

Reinforced yarn has a core (most often made of complex chemical threads), entwined on the outside with cotton, wool or staple chemical fibers. The outer layer fibers must be attached to the core and not move along it. The strength of attachment of the outer layer fibers is determined by their length, strength, coefficient of friction and twist.

Textured yarn has increased volume, porosity, fluffiness, softness and high extensibility. Yarn of this structure can be obtained:

· by shortening high-shrinkage fibers;

· an aerodynamic method, in which the yarn enters a pneumatic nozzle, where it is exposed to turbulent air flows, loosening its structure.

Combination yarn can be elastic and fleecy. Elastic yarn is formed by twisting a core complex synthetic thread with a cotton or woolen sliver. During subsequent heat treatment in a heat chamber heated electrically, the core thread shrinks. By twisting two such threads, a combined yarn is obtained.

Fleecy yarn is produced using an aerodynamic method. When cotton or wool fibers are exposed to a jet of compressed air, they are entangled with complex synthetic threads, resulting in a fluffy yarn with increased bulk.

Comes directly from manufacturers primary filaments. They consist of parallel or loosely twisted filaments, intertwined during the formation process using compressed air. Such threads have a fairly smooth surface and resemble a regular flat twist thread.

Secondary twist threads obtained by twisting two or more primary filament threads. When twisting filament threads of different fibrous compositions, a heterogeneous filament thread is formed. When twisting a filament thread with yarn, twisted composite threads are obtained.

Depending on the degree of twist, there are flat twist threads (up to 230 cr./m), used in knitting production, as well as in the production of lining and some types of dress fabrics, medium twist threads - muslin (230...900 cr./m) , used in the production of dress fabrics, and high-twist crepe threads (1500...2500 cr./m). Threads of high (crepe) twist expand the possibility of obtaining structural effects of fabrics; they are characterized by rigidity and elasticity, which reduces the creasing of fabrics.

Twisted threads, like yarn, come with spiral threads, loops, knots and are widely used in silk weaving in the production of dress and suit fabrics. One of the varieties of complex shaped twist threads is mooskrep, which is a crepe twist thread entwined with a flat twist thread that forms small loops. Wool-like fabrics are obtained from mooskrepa.

Textured threads differ from smooth ones in volume, looseness and fluffiness. Due to their crimp, their transverse dimensions compared to the dimensions of their constituent threads are significantly increased. The air layers formed between the threads improve the heat-shielding properties of products made from them. Textured threads are deformed under the influence of external forces due to the straightening of the curls. Stable crimp causes them to quickly restore their original shape after removing the load. According to the classification proposed by F.Kh. Sadykova, textured filament threads are divided into three types according to their structure: high (100% or more), increased (up to 100%) and normal (up to 30%) elongation.

High-tensile threads include threads obtained by knitting and unraveling and elastic threads. The knitting-unraveling method produces threads with flat crimp. The process of their manufacture consists of the operations of knitting a tubular tape, fixing it in a curved position by heat treatment and unraveling the tape.

Elastic threads are formed from two polyamide thermoplastic threads with high right and left twist. After the spiral arrangement of turns is fixed by heat treatment, the threads are untwisted, spliced and slightly twisted together. A thread with spiral convolutions is formed, some of which twist and loop (Fig. 4, A).

Threads of increased extensibility include maron made of polyamide threads and melan, belan made of polyester threads with a spiral crimp. They are obtained in the same way as described for elastic threads, but to reduce elongation they are subjected to additional processing in a heat chamber or autoclave. Externally, the threads are maron and belan (Fig. 4, b) differ little from elastic threads.

Aeron, produced by an aerodynamic method, belongs to threads of normal extensibility. A complex thread in an untensioned state is exposed to turbulent flows, which separate it into individual elementary threads. As they bend, they form tiny loops intertwined with each other (Fig. 4, V).

Combined threads consist of complex threads and yarn, or monofilaments and yarn, or complex threads that differ in chemical composition or structure, or from yarns that differ in fibrous composition and structure.

Complex threads from natural silk can be obtained by gluing and twisting. When cocoon threads are glued together with sericin, raw silk is formed when the cocoons are unwound. Twisted natural silk can be obtained by single or double twisting. Like filament threads made from chemical fibers, twisted natural silk can be flat twist, medium twist (muslin), high twist (crepe); When twisted twice, a base is formed.

Monofilament can be of different thicknesses and have a round, flat or profiled cross-section. Alunit (Lurex) - ribbons 1...2 mm wide made of aluminum foil with multi-colored (usually gold or silver) coatings with polyester film. Alunit is used in fabrics for a decorative effect. Its disadvantages include its low strength. Plastilex - strips of polyethylene film onto which sprayed metal is applied in a vacuum. Plastilex is stronger than alunit and has some elasticity. Metanite - metallized threads of rectangular cross-section. They are used to produce dress and decorative fabrics with a shimmering shine.

Basic characteristics of the structure and properties of textile threads. The main indicators of the properties of textile threads include linear density, breaking force And elongation at break, number of torsions And twist factor, twist amount. The unevenness of indicators for the listed characteristics is also of great importance.

There are linear densities actual, nominal, nominal-calculated and normal.

Actual linear density threads T f found by weighing them and subsequent calculations using the formula:

Tf = 1000Σm l n,

where 1000 is the coefficient for converting meters to kilometers;

Σm - sum of masses of thread segments, g;

l- length of the thread section, m;

p - number of segments.

The linear density of the thread designed for production is called nominal. According to the nominal linear density of the thread Tn calculate the mass of the material. The deviation of the actual linear density of the thread from the nominal one, %, is determined by the formula:

T=100(T f -T n)/ T n;.

For some calculations it is necessary to know the diameter of the thread. Knowing the linear density of the thread (or its number), you can find the diameter of the thread using the formula:

d = A√T/31.6.

Experimentally found coefficients A are given below.

Raw Material Ratio A

cotton................................................... 1.19. ..1.26

linen........................................................ .......... 1.00... 1.19

wool................................................... ......... 1.26... 1.76

viscose........................................................ ................. 1.26

nylon........................................................ ....... 1.19... 1.46

Complex viscose threads........................ 1.03... 1.26

When twisting threads of the same thickness, the nominal linear density of the thread is determined by the formula:

T r =T o n,

Where T 0 - linear density of a single thread, tex; p - number of twisted threads.

When twisting threads of different thicknesses, the nominal calculated linear density of the thread is established by the formula:

T r =T 1 +T 2 +…+T n

Since when twisting the component threads are arranged in spiral turns, twisting occurs, i.e. shortening the length of the original thread. Moreover, from threads length l 1 it turns out a twisted thread of length l 2. The amount of twist U is determined by the formula:

U=100(l 1 -l 2) / l 1

As a result of twisting, the linear density of the thread increases. Taking into account the twist, the linear density of the thread is called normal.

The twist of the threads is determined number of torsions (turns) peripheral layer of the thread per unit of its length. When twisting, fibers or threads are arranged along helical lines with a given angle of twist. The greater the torsion angle b, the more strongly the thread is twisted. At the same angle b, the number of twists per unit length of a thick thread is less than that of a thin thread. This is clearly visible in Fig. 2.16, which schematically shows the unfolded turns of the peripheral layer of the thread with diameters d 1 And d2. The higher the step height h 1, or h 2 those less number torsion K per unit length of thread.

Rice. 4. Scheme of deployment of turns of the peripheral layer of thread

The degree of twisting of threads of different linear densities T is characterized by the twist coefficient. The twist coefficient α is calculated using the formula:

where K is the number of twists per 1 m of thread.

At a constant thread density δH, the twist coefficient α is proportional to the tangent of the torsion angle b. The torsion angle b is a universal characteristic of the twist of threads of any linear density T and thread density δ H. The number of twists K is determined by the formula:

K=8911tg b √ δ N /T.

Depending on the purpose of yarn and filament threads, as well as the properties of their constituent fibers, the twist coefficient changes.

With a gentle twist, the thread turns out to be less strong, but softer; with a high twist, it becomes strong and rigid. Under the influence of radial stresses arising during the twisting process, the fibers are compressed more tightly, the diameter of the thread decreases, the friction between the fibers increases and the strength of the yarn increases. Thus, as the twist ratio and twist angle increase, the strength of the yarn increases. However, this occurs up to a certain limit called critical twist. Further twisting leads to a decrease in the strength of the thread due to overstrain of the fibers stretched by twisting.

The main characteristics of the mechanical properties of threads include breaking force Рр - the greatest force, cN, withstood by the thread at the moment of breaking, and breaking elongation - the increment in the length of the thread at the moment of its breaking, expressed in absolute units or percentages. To compare the strength of threads of different thicknesses, the concept of relative breaking force per unit linear density of the thread is introduced:

The resistance of threads to destructive forces is determined by the structure and properties of their constituent fibers: the molecular and supramolecular structure of polymers, the strength of bonds in and between molecular chains, the shape and length of molecules, the degree of their straightening and orientation relative to the fiber axis, as well as the structure of the threads themselves.

The strength and elongation of filament threads depend mainly on the mechanical properties of their constituent elementary threads. However, if the elementary threads are unequally straightened and oriented, have different strength and elongation, then overstresses occur in certain sections of the threads, a stepwise break occurs, which significantly reduces the strength of the threads.

In yarn, fibers of limited length are held by friction, so the strength of the yarn depends not only on the mechanical properties and uniformity of the fibers, but also on the type of their surface, shape and length, degree of orientation, straightening and twisting of the fibers in the yarn. When the yarn breaks, only part of the fibers are torn, the rest are pulled apart. The fiber strength in carded yarn is used by 40..50%, in hardware yarn - by 20..30%. This largely explains the greater strength of filament threads than yarn. The tensile characteristics of yarn and threads (according to F.Kh. Sadykova) are given in table. 1.

Table 1 - Indicators of tensile characteristics of yarn and threads

Security questions

Give the classification of textile fibers and threads.
What fibers are natural?
What fibers are considered artificial?
What supramolecular structures of fiber-forming polymers do you know?
Name the main characteristics of the properties of fibers and threads.
What units of linear density do you know?
What is conditional humidity?
Name the natural fibers based on cellulose.
Name the natural fibers that are based on proteins.
How are wool fibers classified based on their structure?
Name the main stages of obtaining chemical fibers and threads.
What types of hydrated cellulose fibers do you know?
What are the structural features of cellulose acetate fibers?
What polymers are used to produce synthetic fibers?
What spinning methods do you know?
What characterizes the degree of twisting of the threads?
What is relative breaking force?

In modern textile production, a wide range of threads of various structures is used. In addition to classical types of yarn, complex, combined threads and monofilaments, film threads and thread-like knitted, woven, braided textile products (chains, cords, ribbons, braid, etc.) are used.

Textile thread is a textile product of unlimited length and relatively small cross-section, consisting of textile fibers and (or) filaments (GOST 13784--94). The structural elements of a textile thread can be connected by gluing, twisting, or, in the case of filament threads, without twisting.

All textile threads can be divided into the following groups: monofilament threads, complex threads, yarn, film threads and combined threads. In terms of their fibrous composition, they can be homogeneous, consisting of one type of fiber or threads, and heterogeneous (in the case of yarn, mixed), consisting of fibers or threads of different chemical compositions.

Depending on the number of folds and twisting operations, single, caned, single-twist and multi-twist threads are distinguished. Single thread is an untwisted or twisted thread obtained in one spinning operation. Troweled thread consists of two or more single strands joined without twisting. Single twist thread consists of two or more single strands twisted in one operation. Multi-twist thread obtained by one or more twisting operations of two or more textile threads, at least one of which is single-twist.

Monofilament. Textile monofilament, or monofilament thread, is a filament of sufficient thickness and strength to be suitable for the manufacture of textile material. Natural monofilament is horsehair, which is used in the manufacture of cushioning materials. Chemical monofilaments are made from synthetic polymers (most often polyamide). They have a round or flat profiled cross section. In the latter case, due to the presence of flat edges, the threads acquire increased shine.

Monofilaments include metallic threads. In ancient times they were made of gold and silver. Currently, they are produced by drawing (pulling) from copper or its alloys or by cutting aluminum foil into strips. A thin layer of gold or silver and a protective film are applied to the surface of such threads. The most famous metal threads: portage- round thread; flattened- flat thread in the form of a ribbon; gimmick-- a spiral thread obtained from fiber or rolled wool. Lurex, or alunit,-- ribbons 1-2 mm wide made of aluminum foil coated with color (often gold or silver) with polyester film. The disadvantages of these threads are their low strength, fragility and rigidity.

Monofilaments also include film threads obtained by cutting a polymer film or extruding in the form of a strip. Films can be transparent and opaque, colored and with metal spraying(for gold, silver, bronze, mother-of-pearl, etc.). Sometimes film threads are slightly softened and deformed by heat treatment, creating the effects of surface unevenness.

Metal and film monofilaments are most often used as backings to create decorative effects in the appearance of textile materials.

Complex threads. Complex threads (multifilament) are a textile thread consisting of two or more elementary threads, the length of which is equal to or slightly greater than the length of the complex thread.

In structure simple complex threads the elementary threads are located more or less parallel to each other, so the surface of the threads is even and smooth (Fig. 1.11, A).

Twisted chemical filament yarns- these are primary filament threads obtained from manufacturing plants, consisting of parallel or weakly twisted elementary threads. They have a smooth, even surface.

Twisted complex threads can be single-twisted or multi-twisted (Fig. 1.11, b). Depending on the degree of twist, threads are distinguished: flat twist (up to 230 kr./m), medium twist - muslin (230--900 kr./m) and high twist - crepe (1500 - 2500 kr./m) . The elementary threads in the structure of twisted threads are located along helical lines, and therefore turns are noticeable on the surface of the threads, the density of which and the angle of inclination relative to the longitudinal axis increase as the degree of twist increases. Crepes are distinguished by significant rigidity, elasticity and unbalanced twist, which causes them to wriggle and twist in a free state, forming twists.

Complex threads from natural silk can be obtained by gluing and twisting. When several silk cocoons are unwound, they stick together to form a thread ( Raw silk). Fluctuations in the shape and size of silks, their unequal tension when unwinding from cocoons, uneven distribution of sericin over the surface and, consequently, gluing density significantly affect the uniformity of the structure of raw silk. Twisted threads are obtained by single or double twisting from mulberries from which sericin has been largely removed.

Low twist (silk weft), medium twist (muslin) and high twist (crepe). With double torsion you get silk base.

Textured thread is a chemical complex thread with a structure modified by additional processing (Fig. 1.11, c, d). Elementary threads have a stable crimp, due to which textured threads are characterized by increased volume, looseness and porosity. Materials made from textured threads have good drapability, dimensional stability and hygienic properties. Distinctive feature textured threads - increased elongation (up to 400%) with a high proportion of reversible deformation. Thanks to this, products made from them retain their shape well. According to the classification proposed by F.K. Sadykova, textured threads are divided into three types according to their breaking elongation indicators: normal elongation (up to 30%), increased or medium elongation (30-100%) and high elongation (more than 100%).

Most existing texturing methods are based on mechanical impact onto complex threads (torsion, corrugation, pressing, etc.) with simultaneous heating to stabilize changes in the shape of the elementary threads. Therefore, thermoplastic threads (polyamide, polyester, triacetate) are most often subjected to texturing. The most common texturing method is the false twist method. The primary filament thread is twisted up to 2000-4000 cr/m, followed by thermal fixation of the twist. When the thread is untwisted to its original state, the elementary threads, under the influence of internal stresses, trying to maintain a fixed shape, bend and take on a complex spatial shape. The complex thread acquires greater fluffiness, volume and high elongation. Using this method, highly elastic polyamide threads of the type elastic(see Fig. 1.11, V). To obtain threads with increased elongation, the twist value is reduced to 2000-2500 cr/m and the threads are subjected to secondary heat treatment after untwisting. This reduces the internal tension of the structure and fixes the curved shape of the filaments, resulting in reduced elongation. High tensile threads include: polyamide -- maron, polyester -- Malan(see Fig. 1.11, d), Belan.

Flat crimp of elementary threads can be obtained by corrugating a complex thread of small twist (up to 100 cr./m) in a heat chamber. This textured thread has high volume but less elongation than false twist threads. In our country, threads are obtained using this method corrugated

The knitting method of producing crimped threads involves unraveling a pre-heat-fixed knitted fabric. One of the advantages of this method is the ability to regulate the stretchability, crimp, and fluffiness of the threads by changing the parameters of the fabric structure.

The method of drawing along an edge is that when a steel plate or knife is pulled along a heated edge, the thread is subjected to severe deformation. The side adjacent to the edge is compressed, and the opposite side is stretched. During continuous movement, the thread constantly turns with its outer side towards the blade, which leads to alternating areas of tensile and compressive deformation along its entire length. Next, the thread is cooled and additionally heat-fixed. As a result, individual elementary threads take on the appearance of a convoluted spring with in different directions turns. In Russia, using this method, they produce a thread called rilon. Abroad, this method was called eji-lon (after the name of the thread).

The aerodynamic method of changing the structure of complex threads is based on the effect of air flow on them in a special chamber. A stream of air separates and bends the elementary threads into loops and entangles them with each other. Distinguish pneumatic - connected threads, having a compact structure, and pneumatic - textured threads, having increased volume and (or) extensibility (GOST 27244-- 93). The aerodynamic method makes it possible to obtain textured threads not only from thermoplastic, but also from other types of chemical threads (viscose, acetate). Abroad, such threads have common name Taslan, in Russia -- aeron(Fig. 1.11, d).

The group of textured threads includes complex threads obtained from bicomponent elementary threads with stable crimp.

Yarn. This is a textile thread made from staple fibers, usually by twisting (GOST 13784 -- 94).

Yarn is produced from natural fibers (cotton, flax, wool, silk) and chemical staple fibers (viscose, polyester, polyamide, polyacrylonitrile, etc.). Depending on the fiber composition, the yarn can be homogeneous, Consisting of fibers of the same type, and mixed- from a mixture of two or more types of fibers. Homogeneous or mixed yarn made from multi-colored fibers is called melange. When creating mixed yarn, the composition of the mixture and its proportions are selected in such a way as to make maximum use of the positive properties of the constituent fibers and neutralize the negative properties. When mixing natural and chemical fibers, take into account the consistency of their sizes (thickness and length) and shape (crimp, profile, roughness). For example, when mixing wool and chemical fibers, the latter must have a stable crimp. Therefore, bicom - porous fibers are often used in these mixtures.

Based on their structure, yarn is distinguished between single, caned and twisted. Single yarn is formed on spinning machines when twisting elementary fibers. Spun yarn consists of two or more folded threads that are not twisted together. This gives the yarns greater balance than single or twisted yarns, which is why they are often used in knitting. Twisted yarn obtained by twisting two or more threads. Single twist yarn is spun from two or three single strands of equal length. Multi-twist yarn is obtained as a result of two or more successive twisting processes; More often than not, two single-twist yarns are connected. When producing twisted yarn, it is desirable that the direction of twisting be opposite to the twist of the constituent threads. In this case, during the final twist, the component threads are untwisted until they are secured by turns of repeated twist. As a result, the component threads bend around each other, arranged in spiral turns, and form a dense, rounded thread, evenly filled with fibers.

The formation of yarn from the fibrous mass occurs during the spinning process - the most ancient method of producing textile threads. The classic process of spindle spinning consists of a number of operations: loosening and scuffing, carding, leveling and drawing, pre-spinning and spinning. The main purpose of these operations is to divide the fibrous mass into individual fibers, clean them of impurities and dust, mix them evenly, straighten them to one degree or another and orient them in the longitudinal direction, form a thread of the required thickness and give it the necessary twist. At the first stage, the fibrous mass, which is often supplied in the form of compressed bales, is separated into small shreds under the impact of disintegrants and scrapers and cleaned of impurities and dust. There are two types of carding operations: carding and combing. In carding, fiber scraps are combed using needle-shaped (carded) surfaces into individual fibers, which removes remaining impurities, tangled fiber scraps and partially short fibers. The combed fibrous canvas is formed into a rope called tape. Subsequently, the tapes are repeatedly folded and stretched, as a result of which the tapes are aligned in thickness, fibers are straightened and oriented in the longitudinal direction. The strips are subjected to a combing operation, and in addition to straightening and orienting the fibers, short fibers are combed out. In the process of pre-

GO spinning slivers are pulled out and lightly twisted, forming RovniTsu. The final spinning is carried out on ring spinning machines, on which the roving is drawn-thin to the required thickness and acquires its final twist. Depending on the set of operations and the number of their repetitions, three main spinning methods are distinguished: hardware, card and comb.

The hardware spinning process is the shortest. After loosening and fraying, the fibrous mass is subjected to two or three carding, after which the fibrous web is divided into strips and rolled (twisted) into roving and then converted into yarn on a spinning machine. Hardware yarn It is produced from short-fiber cotton, wool and a mixture of them with chemical fibers. In addition, fibers from spinning waste and regenerated fibers (from scrap) are added to them. The structure of hardware yarn is loose. It consists of slightly straightened and slightly oriented fibers (Fig. 1.12, A). The yarn has increased porosity and, therefore, good heat-insulating properties, which are important for winter clothing. Cotton hardware yarn is produced with a linear density of 85 - 250 tex and is used for the manufacture of flannel and cotton cloth. Woolen and wool blend hardware yarn has a linear density of 50-300 tex; It is used to make drapes, cloth, coat fabrics, and, less commonly, costume and dress fabrics.

Rice. 1.12. Yarn structure: A - hardware; b - carded; IN -- pneumomechanical

The card spinning system includes all operations except combing. Carded yarn It is produced from medium-fiber cotton and chemical fibers, from a mixture of cotton or viscose with cottonized linen and synthetic fibers. Carded yarn consists of relatively straightened and oriented fibers, which are arranged along helical lines, moving from the center to the periphery and back (Fig. 1.12, b). The structure of the yarn is somewhat unbalanced, since the tension of the fibers located in the outer layers is greater than in the central ones. Carded yarn is not always uniform in thickness, which in turn can cause uneven twist distribution and the appearance of twists and loops. Cotton carded yarn has a somewhat fleecy surface due to the protruding ends of the fibers. Yarn made from chemical fibers of uniform length and thickness has a smoother surface and is more uniform in thickness and twist. Carded yarn is produced with a linear density of 15 - 85 tex and is used for the manufacture of fabrics, knitted fabrics and some types of non-woven fabrics.

The comb spinning system lasts the longest; it includes all types of operations: loosening, carding, repeated folding and drawing of ribbons, combing, in which short fibers are combed out, pre-spinning and spinning. Combed yarn It is produced from long-fiber cotton, flax, long fibers of fine, semi-coarse and coarse wool, silk fibers. The structure of combed yarn is the most ordered; straightened and longitudinally oriented fibers are evenly distributed along the length and cross-section of the yarn. When spun, the fibers are arranged in spirals and tightly wrap around each other. The surface of combed yarn is smooth and less fleecy than that of carded yarn.

Combed yarn from cotton, chemical and mixed fibers is produced with a linear density of 6-20 tex and is used in the production of blouses, shirts, dresses, raincoats, suit fabrics and knitted fabrics. Woolen and wool blend combed yarn from fine wool has a linear density of 19 - 42 tex and is used for the manufacture of worsted dress, suit and coat fabrics and outer knitwear. From semi-coarse and coarse wool mixed with chemical fibers, combed yarn with a surface density of 28 - 84 tex is obtained. Combed linen yarn is most often produced with a linear density of 30-170 tex and is used in the production of table and bed linen.

In addition to classical types of spinning, spindleless spinning systems (pneumo-mechanical, electrostatic, etc.) have become widespread in yarn production. Most often, rotor spinning is used, which is based on the principle of mechanical and aerodynamic influence on the fibers. Tape fibers air flow fed into the spinning chamber, which rotates at a frequency of 30,000 rpm. By centrifugal force, the fibers are pressed against the walls of the chamber, grouped in a chute in the form of a fibrous ribbon, twisted and exited the chamber in the form of yarn.

Due to the peculiarities of molding rotor yarn has a layered structure with different densities of fibers in the cross section (Fig. 1.12, V). The highest density of the central layer decreases towards the outer layers. This leads to a decrease in yarn strength. Compared to carded yarn, pneumatic yarn has higher twist (by 10 - 15%) and bulk (by 10%) and lower surface hairiness. Materials made from rotor-mechanical yarn are more resistant to abrasion, have greater elasticity and wrinkle resistance compared to materials made from ring-spun yarn. Rotor spinning yarn is produced from |l3 cotton, cotton flax, chemical and mixed fibers.

High bulk yarn obtained from a mixture of multi-shrink fibers, increased elongation (30% or more), bulkiness, Fluffiness and the softness of which is achieved due to shrinkage of aasti fibers as a result of chemical or heat treatment. High-volume yarn can be obtained by aerodynamic processing, as a result of which the air flow loosens the structure and increases its volume.

¦ Film threads. Elementary filaments in the form of film ribbons are obtained either by cutting the film or forwarding NH from the melt, followed by drawing and heat setting. Complex film threads twisted from elementary film threads of small width.

, Fibrillated film thread is a film textile thread with longitudinal stratification into fibrils, Having connections between each other. The structure of such threads is voluminous and fluffy.

Combined threads. The structure of combined threads is formed by combining two or more threads of different types, structure and fibrous composition. There are many options for such combinations. Combined threads can consist of yarns of different fibrous composition and (or) structure; from complex threads of different chemical composition and (or) structure; from yarn and filament thread; from monofilament, textured thread and yarn; from complex and textured thread, etc. (GOST 13784--94). Combined threads can be single-twisted or multi-twisted. They can be divided into simple, reinforced and shaped threads.

Simple combined threads obtained by connecting the constituent threads of approximately the same length. Various combinations of delivery threads make it possible to create a variety of combined threads that differ in structural parameters, physical and mechanical properties and appearance, which, in turn, expands the range of textile materials produced from these threads.

Reinforced threads have a core tightly entwined, braided or covered evenly along the entire length with fibers or other threads. Various types of yarn and complex threads, polyurethane monofilaments or complex threads (spandex, lycra), rubber core, etc. are used as the core.

Reinforced threads have several options for production and structure.

The classic type of reinforced thread is a core thread of any type, wrapped in one or two layers with a cover thread of a different composition . This allows you to combine in one thread the properties inherent in the constituent threads. For example, using a chemical filament thread as a core thread and a covering thread made from natural fibers, a strong elastic thread with good hygienic properties is obtained. If highly elastic threads (lycra, spandex, rubber vein) are used as the core, which are in a stretched state during twisting, then after removing the load, a high-volume, fluffy elastic thread is obtained. A type of reinforced thread is mooscrepe, which is a crepe twist thread entwined with a flat twist thread. The shrinkage of the core gives the surface of the thread volume and fluffiness.

Another type of reinforced thread has a core in the form of yarn or filament thread, evenly covered with fibers. Such threads are produced by an aerodynamic method by supplying fibers with an air flow into the thread torsion zone, where they are captured by the core thread and firmly fixed in its structure. A variant of such threads is a core thread covered with pneumatically entangled elementary threads.

Velor threads, or chenille, consist of a core single-twist thread, in which many short fibers are fixed perpendicular to the longitudinal axis, creating a velvety surface of the thread

Flocked threads are obtained by applying chopped pile in an electrostatic field to a core thread, previously coated with glue. By adjusting the tension of the core thread and the voltage on the electrodes, you can achieve a uniform radial arrangement of the fibers on the surface of the thread.

Textile threads that have periodically repeating local changes in structure or color (Fig. D. 14). In fancy threads, the core thread is wrapped around a surge or effect thread (sometimes several) of greater length than the main one. The local effects that occur in fancy threads and determine their name are very numerous and varied. These can be round or oblong nodules (nodular thread); small loops in the form of rings (loop); large fluffy loops (boucle); alternation of noticeable thickened and thin areas (overtraced); periodic change in the density and "inclination of the turns of the surge thread around the core (spiral); 1®spun lumps of colored fibers (neps); alternation of spirals and loose multi-colored knots (ponge), etc. There are ((shaped threads with sections of film woven into the structure "Threads. Flocked shaped threads have a pile on the surface, (Different in length, thickness, color, density of arrangement. Thanks to shaped threads, textile materials with a variety of surface textures are obtained. Shaped threads can be produced by the method of pneumatic entangling of complex threads, with periodic formation of loops on the surface threads

Recently, sometimes when creating textile materials, thread-like textile products in the form of ribbons, braid, cords, etc., obtained by knitting, weaving or braiding, are used as threads. The greatest variety is found among “knitted” threads (Fig. 1.15), the simplest of which are produced in the form of a ribbed chain or a warp-knitted ribbon. In reinforced knitted threads, the role of the core is played by a chain into which perpendicularly located sections of fibers can be woven

Rice. 1.14. A - loopy; b -- spiral; V - with a roving effect; G -- pongee; d -- Nodular

textile thread yarn

Main characteristics of the structure and properties of textile threads. The main structural characteristics of textile threads include linear density, twist direction, twist, twist factor and twist amount.

The thickness of textile threads can be determined by linear dimensions and cross-sectional area measured under a microscope. However, often the complex shape of the section, the presence of channels, voids and different densities of elementary fibers make it difficult correct assessment thread thickness. Therefore, linear density, which has the conventional name tex (from the word textile), has been adopted as a standard characteristic of thickness.

Linear density represents the ratio of the mass of the thread T, mg, to its length L, m:

There are nominal, nominal-calculated, and actual linear densities.

Nominal Tn is called the linear density of the thread designed for release. It is used in calculating the structural parameters of textile materials. Nominal-calculated density Tr caned and twisted threads are calculated by summing the linear density of the constituent threads

For multi-twist thread

Rice. 1.15. Knitted threads: A - elastic chain; b- flat “brush”; V -- with non-woven tape.

When twisting threads, the length of the constituent threads is shortened, the amount of which is called twisting U, %. Ras

Twisting is the main method of producing yarn from short fibers, complex and combined yarns. The degree of twisting of the threads is assessed by the following characteristics.

The direction of twist characterizes the location of the turns of the peripheral layer of the thread: when right twist (Z) the components of the thread are directed from left to top to right, with left twist(S) -- from right to top to left (Fig. 1.16). To obtain balanced and strong threads, the twist directions during the first and subsequent twisting processes must be opposite.

Rice. 1.16.

The standard characteristics of the degree of twist are thread tension and twist coefficient.

Therefore, with a gentle twist, the thread turns out to be less strong and softer, and with a high twist, it becomes stronger and stiffer. An increase in the strength of a thread with an increase in its twist occurs up to a certain limit (critical twist), after which a decrease in strength occurs. This is due to overstressing of the outer fibers or threads stretched by twisting. However, in practice, to obtain low-crease fabrics with a beautiful fine-grained surface, threads with a crepe twist exceeding the critical twist are sometimes used.

The structure of the yarn is characterized by hairiness, the presence of protruding fiber tips on the surface, and both the number and length of the fibers are important. If the yarn has noticeable hairiness, then the surface structure of the fabric or knitted fabric is less pronounced, and after the finishing operations of napping and rolling, a covering is formed that, to one degree or another, completely covers the weave pattern. Materials with a clearly defined surface texture require threads with low hairiness. The degree of hairiness depends on the spinning method, the amount of twist, and the crimp of the fibers. The number of hair fibers is most often used as a characteristic of hairiness. pv, per unit length of thread (usually 1 m), the average length of the fibers /, mm, and the total or total length of the fibers bd, mm.