Features of the production and use of synthetic fabrics. New types of synthetic fibers Synthetic fibers interesting facts

Obtained from polymers that do not exist in nature, obtained by synthesis from natural low molecular weight compounds. A variety of raw materials and a variety of properties of the original synthetic polymers make it possible to obtain fibers with different, predetermined, characteristics.

The ability to pre-set the necessary properties of the fabric is of great importance for the modern textile industry. Products of the new generation are more adapted to the needs of the human body, have multifunctional and comfortable properties.

Synthetic fibers are actively used for the production of overalls, clothing for extreme conditions and sports.

Currently, there are several thousand types of synthetic fibers, and their number is growing every year. The most common will be discussed below.

Polyurethane fibers

In terms of mechanical properties, polyurethane fibers are in many ways similar to rubber threads, because capable of highly elastic reversible deformations. Such fibers give textile materials high elasticity, abrasion resistance, resilience, dimensional stability, crease resistance. They are rarely used in their pure form. Their participation in the fabric is most common as carcass threads, around which other threads are wound. The disadvantage of such fibers is low thermal stability. Already at 120 C, polyurethane fibers in the stretched state significantly lose strength.

The main representatives of polyurethane fibers are such trade names as elastane, lycra, spandex, neolan, etc.

Polyamide fibers

A distinctive property of polyamide fibers is increased resistance to abrasion, exceeding cotton by 10 times, wool by 20 times, and viscose by 50. They are also distinguished by high dimensional stability. Among the shortcomings, it is necessary to note the low resistance to light and the action of sweat. In the light they turn yellow and become brittle. In addition, such fibers have low hygroscopicity and are subject to strong pilling. However, many of their shortcomings can be eliminated by introducing various stabilizers. Often polyamide fibers are added to mixed fabrics (with cotton, wool, viscose) in a part not exceeding 10-15%, which practically does not worsen the hygienic properties of the products, but significantly improves the mechanical ones. The fibers are widely used in the production of hosiery and knitwear, for the production of sewing threads and haberdashery.

Main trade names: capron, anid, nylon, tactel, meryl, etc.

polyester fibers

The main property of polyester fibers is increased heat resistance, surpassing the performance of all natural and most chemical fibers. The production of such fibers currently occupies a leading position among chemical fibers due to their high physical and mechanical properties. They have great elasticity and high abrasion resistance. Fabrics made from such fibers hold their shape well, do not wrinkle, and have a low degree of shrinkage. The disadvantages are increased rigidity, a tendency to peeling, strong electrification and low hygroscopicity. Disadvantages are eliminated by modifying the feedstock. From polyester fibers mixed with natural materials (cotton, wool, linen), as well as viscose, shirt, dress, suit and coat fabrics, as well as artificial fur, are successfully produced. At the same time, such a disadvantage as creasing is eliminated, the abrasion resistance increases while maintaining hygienic properties.

Trade names: lavsan, polyester, terylene, etc.

Polyacrylonitrile fibers

Such fibers are called "artificial wool" due to the proximity of their mechanical properties. They have high light resistance and heat resistance, sufficient strength, keep their shape well. Among the shortcomings, it is worth noting the low hygroscopicity, the tendency to form pills, stiffness and electrification. However, all disadvantages are eliminated by modification. In the sewing business, they are mainly used for tailoring outerwear mixed with wool, faux fur.

Trade names: nitron, acrylic, acrylan, cashmere, etc.

Polyolefin fibers

A distinctive feature of polypropylene fibers is their low density. These are the lightest of all fiber types. In addition, their hygroscopicity is almost zero, so they do not sink in water. Such fibers have good thermal insulation properties. The disadvantage is low heat resistance (115 C), which can be leveled by modification. It is optimal to create two-layer materials, in which the lower layer is made of polyolefin fibers, and the upper layer is made of hygroscopic cellulose fibers. This technology allows the bottom layer to remain dry, but wick moisture away to the hygroscopic top layer. It is often used when sewing underwear, sportswear, as well as hosiery with increased hygienic characteristics.

Trade names: Herculon, Ulstrene, Found, Meraklon, etc.

Polyethylene fiber is used mainly for technical purposes. Trade names: spectrum, dynema, tekmilon.

PVC fibers

Polyvinyl chloride fibers have high chemical resistance, low electrical conductivity and very low heat resistance (destroy at 100 C). When rubbed, the fiber acquires a high electrostatic charge, which gives the linen made from it medicinal properties in the treatment of diseases such as sciatica, arthritis. In addition, such fibers are characterized by a high degree of shrinkage after heat treatment. This property is used to obtain a beautiful embossed surface of the fabric. In addition, polyvinyl chloride fibers are used in the manufacture of pile carpets, artificial fur, artificial leather.

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Some natural cellulose fibers are processed and processed for specific purposes. Well-known fibers such as viscose, acetate, etc. are obtained by processing various natural polymers.

The first man-made fibers that were developed and manufactured used polymers of natural origin, more precisely cellulose, which is a raw material available in large quantities in the plant kingdom.

Cellulose is a natural polymer that makes up the living cells of all vegetation. It is the material at the center of the carbon cycle and the most abundant and renewable biopolymer on the planet.

Cotton sheets and wood pulp, viscose, copper ammonium silk, cellulose acetate (secondary and triacetate), polynose, high wet modulus (HMW) fibre.

• Cellulose is one of the many polymers found in nature.
• Wood, paper and cotton contain cellulose. Cellulose is an excellent fiber.
• Cellulose is made up of repeating units of monomeric glucose.
• The three types of regenerated cellulose fibers are viscose, acetate and triacetate, which are derived from the cell walls of short cotton fibers called linters.
• Paper, for example, is almost pure cellulose.

Viscose

The word "viscose" was originally applied to any fiber made from cellulose and therefore contained cellulose acetate fibers. However, the definition of viscose was described in 1951 and now includes textile fibers and fibers composed of regenerated cellulose, excluding acetate.

• Viscose is a regenerated cellulose fibre.
• It is the first man-made fiber.
• It has a jagged round shape with a smooth surface.
• When wet, viscose loses 30-50% of its strength.
• Viscose is formed from natural polymers and therefore is not a synthetic fiber, but an artificial regenerated cellulose fiber.
• The fiber is sold as rayon.
• There are two main varieties of viscose fiber, namely viscose and copper ammonium.

Acetate

Derived fiber in which the fiber-forming substance is cellulose acetate. Acetate is obtained from cellulose by refining cellulose from wood pulp with acetic acid and acetic anhydride in the presence of sulfuric acid.

Characteristics of acetate fiber:

• Luxurious to the touch and appearance
• Wide range of colors and glosses
• Excellent drape and softness
• Relatively fast drying
• Resistant to shrinkage, moths and powdery mildew

Special dyes have been developed for acetate because it does not accept dyes commonly used for cotton and viscose.

Acetate fibers are manufactured fibers in which the fiber-forming substance is cellulose acetate. Cellulose ethers triacetate and acetate are formed by acetylation of cotton linters or wood pulp using acetic anhydride and an acid catalyst in acetic acid.

Acetate and triacetate fibers are very similar in appearance to viscose with consistent strength. Elements and triacetates are moderately stiff fibers and have good flexural and deformation resilience, especially after heat treatment.

The abrasion resistance of acetate and triacetate is poor and these fibers cannot be used in applications requiring high abrasion and wear resistance; however, the abrasion resistance of these fibers is excellent. Although acetate and triacetate are moderately absorbent, their absorption cannot be compared to pure cellulose fibers. To the touch, acetate fabrics are somewhat softer and more flexible than triacetate. The fabrics of both fibers have excellent drape characteristics. Acetate and triacetate fabrics have a pleasant appearance and a high degree of sheen, but the sheen of these fabrics can be modified by adding a matting agent.

Both acetate and triacetate are susceptible to attack by a number of household chemicals. Acetate and triacetate are attacked by strong acids and bases and oxidizing bleaches. Acetate has only a slight resistance to sunlight, while the solar resistance of triacetate is higher. Both fibers have good heat resistance below their melting points.

Acetate and triacetate cannot be dyed with dyes used for cellulose fibers. These fibers can be satisfactorily dyed with disperse dyes at moderate to high temperatures, producing crisp, vibrant hues. Acetate and triacetate dry quickly and can be dry cleaned.

Synthetic fibers are chemical fibers formed from synthetic polymers obtained by polymerization or polycondensation reactions from low molecular weight compounds (monomers).

Synthetic fibers compared to artificial fibers have high wear resistance, low creasing and shrinkage, -. but are characterized by low hygienic properties.

A new promising direction in the development of synthetic fibers is the development of technology for the production of ultrathin

fibers (microfibers). It is with them that textile workers associate the possibility of manufacturing comfortable fabrics and knitwear. The use of microfibers makes it possible to obtain materials with improved hygienic properties, fabrics that are soft, elastic, draped, waterproof, and have good hygienic properties.

Polyester fibers (polyethylene terephthalate - PET, lavsan, polyester)- synthetic fibers formed from complex heterochain polymers. Polyethylene terephthalate fibers are spun from a melt of polyester terephthalic acid and ethylene glycol.

In the global production of synthetic fibers, these fibers occupy the first place. Lavsan fiber is characterized by crease resistance, surpassing in this indicator all textile fibers, including wool. So, products made of lavsan fibers are 2-3 times less wrinkled than woolen ones. In materials based on cellulose, to reduce their creasing, 45-55% of lavsan fibers are added to the mixture.

Lavsan fiber has very good resistance to light and atmospheric influences, yielding in this indicator only to nitron fiber. For this reason, it is advisable to use it in curtain-tulle, awning, tent products. Lavsan fiber is one of the heat-resistant fibers. It is thermoplastic, thanks to which the products retain the effects of pleated and corrugated well. In terms of resistance to abrasion and bending, lavsan fiber is somewhat inferior to kapron. The fiber has high strength, the breaking load of the fiber is 49-50 cN/tex, the yarn is 29-39 cN/tex, and good deformability (relative elongation at break is 35^0 and 17-35%, respectively). The fiber is resistant to dilute acids, alkalis, but is destroyed when exposed to concentrated sulfuric acid and hot alkali. Lavsan burns with a yellow smoky flame, forming a black non-rubbing ball at the end.

However, lavsan fiber has low hygroscopicity (up to 1%), poor dyeability, increased rigidity,

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electrified and pilling. Moreover, the pills remain on the surface of the products for a long time.

Polyamide fibers (kapron, dederon, nylon)- a type of synthetic fibers formed from a melt of polyamides - heterochain, polymers containing amide groups in the main chain (- CO - MH 2) and obtained by polymerization methods (for example, from e-caprolactam) or polycondensation of dicarboxylic acids (or their esters) and diamines. The most widespread are nylon fibers formed from poly-e-caproamide, which is a polymerization product of e-caproamide.

The positive properties of nylon fiber include: high strength and deformation properties: fiber breaking load - 32-35 cN / tex, thread - 36-44 cN / tex and elongation at break of 60-70 and 20-45%, respectively, as well as the largest made of textile fibers resistant to abrasion and bending. These valuable properties of kapron fiber are used when it is mixed with other fibers to obtain more wear-resistant materials.

Thus, the introduction of 5-10% kapron fiber into a woolen fabric increases its resistance to abrasion by 1.5-2 times. Nylon fiber also has low creasing and shrinkage, resistance to the action of microorganisms.

At a temperature of 170 ° C, nylon softens, and at 210 ° C it melts. When introduced into the flame, capron melts, ignites with difficulty, burns with a bluish flame. If the molten mass begins to drip, the combustion stops, a melted brown ball forms at the end, and the smell of sealing wax is felt.

However, nylon fiber is relatively little hygroscopic (3.5-4%), so the hygienic properties of products made from such fibers are low. In addition, nylon fiber has sufficient rigidity, is highly electrified, unstable to the action of light, alkalis, mineral acids, and has low heat resistance. On the surface of products made from nylon fibers, pills are formed, which, due to the high strength of the fibers, remain in the product and do not disappear during wear.

Polyacrylonitrile fibers (PAN, acrylic, nitron, or-lon, curtel)- synthetic fibers obtained from polyacrylonitrile or copolymers containing more than 85% acrylonitrile. Gol and acryl nitrile are obtained by radical polymerization of acrylonitrile. Fibers from copolymers containing 40-85% acrylonitrile are commonly called modacrylic.

Nitron - the softest, silkiest and "warmest" synthetic fiber. In terms of heat-shielding properties, it surpasses wool, but in terms of abrasion resistance it is inferior even to cotton. The strength of nitron is half that of nylon, the hygroscopicity is very low (1.5%). Nitron is acid-resistant, resistant to all organic solvents, microorganisms, but is destroyed by alkalis.

It has low shrinkage and shrinkage. Outperforms all textile fibers in light fastness. At a temperature of 200-250 °C, the nitron softens. Nitron burns with a yellow smoky flame with flashes, forming a solid ball at the end.

The fiber is brittle, poorly dyed, highly electrified and pilling, but pills disappear during wear due to their low strength properties.

To eliminate the shortcomings - low hygroscopicity and poor dyeability, a wide range of modified PAN fibers - modacrylic fibers - has been created.

polyvinylchloride fibers. Produced from polyvinyl chloride - PVC fiber and from perchlorovinyl - chlorine. The fibers are distinguished by high chemical resistance, low thermal conductivity, very low hygroscopicity (0.1-0.15%), the ability to accumulate electrostatic charges when rubbed against human skin, which have a therapeutic effect in diseases of the joints. The disadvantages are low heat resistance (products can be used at temperatures not exceeding 70 ° C) and instability to the action of light and light weather.

Polyvinyl alcohol fibers (vinol) obtained from polyvinyl alcohol. Vinol has an average hygroscopicity (5%), the degree of swelling in water is 150-200%, it has a high stability

textile goods

resistance to abrasion, yielding only to polyamide fibers, it is well dyed.

Polyolefin fibers obtained from melts of polyethylene and polypropylene. These are the lightest textile fibers, products made from them do not sink in water. They are resistant to abrasion, chemical reagents, and have high tensile strength. The disadvantages are low light resistance and low heat resistance.

Polyurethane fibers (spandex, lycra, elastin) belong to elastomers, because they have exceptionally high elasticity (extensibility up to 800%). They are light, soft, resistant to light, washing, sweat. The disadvantages include low hygroscopicity (1-1.5%), low strength, low heat resistance.

In table. 2.1 shows the symbols for the types of textile fibers.

Table 2.1Symbols for types of textile fibers

The end of the table. 2.1

Fibers are elongated flexible and durable substances of limited length and small transverse dimensions, suitable for the manufacture of yarn and textiles. We talk about what natural and synthetic fibers are in the article.

Fiber classification

Fiber classification:

• natural - fibers of plant origin (cotton, flax - polysaccharides (carbohydrates) having the composition (C 6 H 10 O 5) x) and animal origin (wool, silk - protein substances consisting of long polypeptide chains).
• chemical , which are divided into artificial fibers and synthetic fibers. Artificial fibers are obtained from the products of chemical processing of natural polymers (cellulose), for example, viscose, copper ammonium, acetate fibers. Synthetic fibers are obtained by chemical processing of synthetic polymers. For example, nylon and capron (polyamide fibers), lavsan (polyester fibers).

Synthetic fiber

Synthetic fibers are polyamide , polyester, polyacrylonitrile, polyvinyl alcohol, polyvinyl chloride, polypropylene, and many others. The former include substances such as kapron, anide, enanth. The main characteristics of these fibers are tensile strength, abrasion resistance. However, there are also disadvantages: low hygroscopicity, low heat resistance and high electrification. This fiber is used in the production of knitwear, thread, lace, ropes and fishing nets.

Rice. 1. Polyamide fibers.

Polyamide fiber does not tolerate high temperatures. If it is heated to 160 degrees, then the strength drops sharply up to 50%.

To polyester fibers include lavsan, dacron, terylene. Fiber has both advantages and disadvantages. The disadvantages include increased rigidity and strong electrification. Lavsan is often used to make fabric for domestic purposes.

Rice. 2. Polyester fibers.

To polyacrylonitrile fibers include, for example, nitron, orlon. Nitron in appearance resembles wool. Nitron is very strong and resilient, and these properties are retained regardless of whether it is wet or dry. However, in terms of abrasion resistance, nitron is inferior to polyamide and polyester fibers.

To PVC fibers include chlorine. Compared to other synthetic fibers, it is less durable, less resilient, and less resistant to abrasion.

Rice. 3. Polyvinyl chloride fibers.

Chlorine has the ability to accumulate electrostatic charges in itself, so it is used for the production of medical underwear.

Polyvinyl alcohol fibers include, for example, vinol. A distinctive feature of this material is high hygroscopicity, these fibers are well dyed with dyes and are used for the production of knitwear, fabrics and carpets.

What have we learned?

All existing fibers can be divided into 2 classes: chemical and natural. synthetic fibers are chemical fibers. They are divided into polyester, polyamide, polyvinyl chloride and many others. The article also provides examples of synthetic fibers.

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artificial fibres. Among the chemical fibers in terms of output, the first place is occupied by artificial viscose fiber. The main substance for the production of viscose fiber is wood pulp and cheap chemicals available. The advantage of viscose fiber is the high economic efficiency of its production and processing. So, in the production of 1 kg of viscose yarn, labor costs are 2-3 times lower than the costs for the production of the same yarn from cotton and 4.5-5 times lower than the production of 1 kg of wool yarn.

Viscose fiber is produced in various lengths and thicknesses. The thickness of the elementary fiber of viscose silk is from 0.5 to 0.2 tex.

Viscose fibers have sufficient strength, but when wet, their strength drops to 50-60%. Their disadvantage is the ability to shrink, i.e., shrink in length, especially after washing the products.

These fibers have high hygienic properties, as they are characterized by the ability to absorb moisture well. Viscose fibers are heat resistant.

When heated, they do not soften and withstand heating without destruction up to 150 °. At higher temperatures (175-200°) the process of fiber decomposition begins.

Viscose fibers with enhanced properties are called polynose. By their properties, they are close to cotton fiber.

Based on cotton or wood pulp, other artificial fibers are obtained - copper ammonia and acetate.

Copper-ammonia fiber in its properties resembles viscose fiber. It is produced in small quantities, since its production is much more expensive than the production of other man-made fibers. It is mainly used in mixtures with wool.

There are two types of acetate fibers: diacetate and triacetate. Diacetate fibers are commonly referred to as acetate fibers. Acetate fibers have sufficient strength. Their breaking elongation is 18-25%. The tensile strength of acetate fiber in the wet state is reduced by 40-50%, and triacetate - by 10-15%. Acetate fiber absorbs about 6.5% of moisture, and triacetate - no more than 1-1.5%.

Acetate fibers in their properties occupy an intermediate position between artificial and synthetic fibers.

Unlike viscose, acetate fibers are thermoplastic and begin to deform at a temperature of 140-150 °.

The use of acetate fibers mixed with viscose can significantly reduce the wrinkling of products. Acetate fibers are not dyed with dyes used for dyeing viscose fibers, so the use of acetate fibers mixed with viscose fibers allows you to create various color effects, ennoble the front surface of the fabric.

Of other artificial fibers, glass and metal are used in the production of fabrics; metal threads are used to give fabrics various decorative effects; they are called alunit, lurex, metlon, etc.

Synthetic fibres. Of the synthetic fibers, polyamide fibers are most widely used, which include nylon, anide, enanth and other fibers. In our country, among polyamide fibers, nylon fiber occupies the first place. To obtain it, caprolactam resin is used, which is obtained by chemical synthesis from relatively simple organic substances.

Polyamide fibers have a number of valuable properties: high tensile strength, resilience and exceptional abrasion resistance.

The advantage of polyamide fibers is their high resistance to abrasion and repeated deformations.