Viscose - what kind of fabric, natural or not, material composition

Greetings, dear reader! Today I propose to talk about one of the most popular fabrics - viscose. Why did she win the hearts of consumers so much? What kind of “pie” is this and what do you eat it with? Let's figure it out together.

1. History of the creation of viscose; 2. Technological process for the production of viscose; 3. What is viscose?; 4. Types of viscose fabrics; 5. Advantages and disadvantages of viscose fabric; 6. Use of viscose fabric; 7. Care of viscose; 8. Customer reviews.

Is viscose a natural, artificial or synthetic material?

Humanity owes the appearance of viscose fiber to the experimental work of Guiller de Chardonnay, who, as a result of research in 1884, was able to obtain artificial material from natural raw materials. Thanks to the developments of this scientist, waste from wood processing began to be used to create a unique material. Viscose is obtained artificially through the chemical modification of cellulose.

The manufacturing technology of the material and its formula have no analogues. According to the description, it resembles cotton, as it does not electrify and quickly deforms. However, the difference between cotton and viscose is that it is softer to the touch and easily smoothes out to return to its original shape.

The disadvantages of matter are easily compensated for by adding synthetic components made from polymers. Synthetics make the fabric more durable and wear-resistant. The properties of the fabric and its structure make it possible to produce from it any model of light summer clothing, warm clothes for cold weather that can retain heat, like wool, as well as products for decorating the home interior.

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Care

Now we will learn how to wash and iron viscose. The material is quite finicky and does not tolerate aggressive influences, be it mechanical manipulation or chemical compounds. Items made from viscose should be washed in cool water. Temperatures above 40 ᵒC will cause shrinkage.

Finding a 100% product is problematic: manufacturers introduce acrylic, polyester, nylon and elastane into the composition, which affect the properties of the fabric and change the rules for caring for it. Does 100% viscose shrink after washing? Unfortunately, yes, and the fabric is also deformed. Mixed fabrics also shrink, but not so catastrophically. Some items can withstand washing at 40ᵒC, which the manufacturer notifies the buyer on the label.

Fabrics with added wool are more sensitive to temperature effects. Such items should only be washed by hand using delicate detergents. Such fabrics cannot be ironed. But light steaming through fabric is allowed.

They don’t wring things out, and if they wring them out in the car, it’s at very low speeds. It is better to lay the washed item on a horizontal surface and let it dry naturally, then ironing will not be required. Cellulose with cotton can be ironed in the “silk” mode.

Dear readers of the Tkan.Club website, if you still have questions on this topic, we will be happy to answer them. Leave your reviews, comments, share stories if you have dealt with this fabric! Your life experience may be useful to other readers.

How are viscose threads obtained?

Natural wood sawdust and wood chips are used to produce viscose fiber. This raw material is waste from wood processing enterprises. To create viscose fabric, wood pulp is subjected to processing, which takes place in several stages:

• creating a spinning substrate by steaming the starting material in a solution containing an alkali;
• passing the resulting mass through a spinneret plate with tiny holes into a mold with acid to form viscose threads;
• thread processing;
• drying.

History[ | ]

The process of regenerating cellulose from a solution by adding acid to its concentrated copper-ammonia (that is, containing copper sulfate and ammonium hydroxide) aqueous solution was described by the Englishman J. Mercer around 1844. But the first industrial application of this method, which laid the foundation for the copper-ammonia fiber industry, is attributed to E. Schweitzer (1857), and its further development is the merit of M. Kramer and I. Schlossberger (1858). And only in 1892, Cross, Bevin and Beadle in England invented a process for producing viscose fiber: a viscous (hence the name viscose) aqueous solution of cellulose was obtained after treating the cellulose first with a strong solution of sodium hydroxide, which gave “soda cellulose,” and then with carbon disulfide ( CS2), resulting in soluble cellulose xanthate. By squeezing a stream of this "spinning" solution through a spinneret with a small round hole into an acid bath, the cellulose was regenerated in the form of rayon fiber. When the solution was squeezed into the same bath through a die with a narrow slit, a film called cellophane was obtained. J. Brandenberger, who worked on this technology in France from 1908 to 1912, was the first to patent a continuous process for making cellophane.

On September 30, 1902, artificial silk (viscose) was patented.

In the USSR, the first production of viscose fibers began to appear in 1927, in the cities of Mytishchi, Leningrad, Mogilev and Klin[1]. The design of the enterprises was carried out by the design institute GIPROIV[2].

History and production process

In 1664, British physicist Robert Hooke worked on obtaining natural fabric from wood raw materials. There was a lack of technical capabilities to implement this process. Therefore, the idea had to be abandoned.

Material range

In 1855, George Oudemars developed a technology for making viscose by hand. He dipped a thin needle into a sticky mixture of rubber, crushed wood, alcohol and ether. In this way the threads must be formed and mined. It was a long and labor-intensive process that could not be continued. The material was easily flammable, so it was again unviable. Only 30 years later, the French chemist Count Guiller de Chardonnay managed to develop a new technology for the production of viscose material.

Viscose material

He patented his invention and founded a company to produce it. The material shone and was fragile, easily flammable. The scientist continued to improve the fabric production technology. In 1889, new types of threads were introduced. In 1892, British chemists Charles Frederick Cross, Edward John Beaven and Clayton Beadle developed a technology for the production of viscose.

Loom

Viscose manufacturing technology:

• Grind the cellulose and boil it in a container with calcium hydrosulfite salt.
• Remove water. Leave the humidity at 6-8%.
• Remove impurities by heating a sodium hydroxide-lye solution. As a result, alkali cellulose is formed.
• Keep the raw materials until ripe. There will be a decrease in the molecular weight of the original cellulose wood.
• Treat raw materials with carbon disulfide. Add alkali solution and mix. The result is a viscose solution containing 85% water.
• Leave the solution for several days to mature and obtain viscosity.

Traditional material production

• To produce the material, use the wet method. The solution is passed through dies. It is sent to precipitation tanks filled with acid.
• The resulting raw materials are used to produce long threads that are wound onto bobbins.

After the threads are formed, they are wound onto bobbins

This is a traditional production method. But today more modern technological processes already exist. However, many manufacturers have not yet perfected their production.

Modern production

Receiving[ | ]

Core technology[ | ]

Dish sponge made of viscose Shawl made of viscose
The production of explosives consists of two successive stages: obtaining spinning mass - viscose and spinning the fiber. The raw material used is wood cellulose containing 95-99% high-molecular fiber-forming fraction with a degree of polymerization of 800-1100.

Obtaining viscose[ | ]

The production of viscose includes the following operations:

• Isolation of cellulose from wood. Since cellulose accounts for only half the mass of wood, the cellulose is first extracted. To do this, the wood is placed in a solution of calcium hydrosulfite and boiled under pressure in closed boilers for 24 hours. In this case, the bonds between the cellulose fibers are destroyed. Water is then added to the pulp and applied to the conveyor. After this, it is dried and cut into sheets. The result is sulfite cellulose, which is used both for the production of paper and for the production of viscose[3].
• Treatment of cellulose with a 20% solution of sodium hydroxide (mercerization) for 5-115 minutes at a temperature of 45-60 ° C. This forms an additive compound of cellulose with alkali: (alkali cellulose) (a) and cellulose alcoholates (b). Simultaneously with reactions (a) and (b), during mercerization, swelling of cellulose and dissolution of hemicelluloses occur, which promotes the diffusion of the esterifying agent into the fiber during subsequent xanthogenation of alkali cellulose.
• Squeezing the suspension to remove excess sodium hydroxide solution on a squeezing press until the degree of squeezing (weight ratio of squeezed alkali cellulose and suspension) is 0.33-0.36.
• Grinding of pressed alkali cellulose.
• Oxidative destruction (pre-ripening) of alkali cellulose due to its oxidation with air oxygen on a conveyor or in special devices for 1.5 - 2 hours at a temperature of 50 - 60 ° C. During the pre-ripening process, the degree of cellulose polymerization decreases to 400-600.
• Xanthogenation. The process of xanthogenation involves treating alkali cellulose with carbon disulfide, resulting in the formation of a new chemical compound - cellulose xanthate, which can dissolve in a dilute solution of sodium hydroxide.
• Transferring cellulose into solution to produce viscose. As a result of treating cellulose with a concentrated solution of sodium hydroxide and carbon disulfide in previous stages, it acquires the ability to go into solution, necessary for spinning the fiber. Cellulose is dissolved in a 4% sodium hydroxide solution and kept for several days, as a result of which it “ripens” - viscose is obtained[3].

Xanthogenation of alkali cellulose is carried out in hermetically sealed batch devices - xanthogenators. The xanthogenator is equipped with a cooling jacket, there is a horizontal stirrer inside, loading and unloading hatches, and safety valves on the body. Communications for carbon disulfide, water, alkali, nitrogen, suction of carbon disulfide vapor and vacuum creation are provided.

2200 kg of alkali cellulose is loaded into the xanthogenator using pneumatic transport from a hopper scale. After loading, the alkali cellulose is brought to the initial xanthogenation temperature (18...22) °C ± 0.5 °C by feeding supercooled water into the xanthogenator jacket in summer and river water in winter. Upon reaching the initial temperature of xanthogenation, carbon disulfide is supplied to the xanthogenator in an amount of 30...36% of the mass of alpha cellulose.

The beginning of the supply of carbon disulfide is considered the beginning of the xanthogenation process, which lasts 60...75 minutes. When the xanthogenation process is completed, a solvent alkali cooled to 5±1 °C is supplied to the xanthogenator through a counter in an amount determined by calculation. Of the estimated amount, 1000...1500 liters of solvent alkali are left for washing the xanthogenator after unloading.

Fiber spinning[ | ]

After obtaining viscose, the fiber is spun. To do this, in the spinning shop, viscose is filtered and passed through dies - metal caps with many small holes, entering a precipitation bath, for example, with sulfuric acid, where the xanthate, which was needed to transfer cellulose into solution, undergoes hydrolysis and cellulose is formed again, but already in the form of long fibers. The fibers from one spinneret are connected into one thread in some way. To obtain staple fiber, the threads are cut into pieces of short length[3].

Technology for producing viscose fiber using a semi-continuous method[ | ]

A completely different possibility of producing fine assortment viscose textile threads is shown by using a semi-continuous principle that implements high-speed wet spinning.

Other technologies for producing viscose fiber[ | ]

Lyocell[ | ]

The production of viscose fibers (lyocell) became possible based on the processes of direct dissolution of cellulose in N-methyl-morpholine-N-oxide (NMMO) [4][5].

The production of viscose fibers using the MMO process based on cellulose carbamate on an industrial scale began in 1992 in the UK, which produced the first 18 thousand tons of this fiber. Ready-made hydrated cellulose entered the market under different names assigned to it by the companies that own the brands: lyocell or lyocell in English pronunciation, newcell, tencel, orcell.

The technological process for producing viscose fibers using the MMO method consists of the following main stages [6]:

1. Preparation of cellulose (crushing and obtaining pulp or powder, depending on the technology).
2. Addition of methyl morpholine oxide (MMO) to cellulose pulp or powder.
3. Mixing in an extruder heated to 100 °C.
4. Feeding the solution into the precipitation bath, followed by painting and drying.

The advantages of this process and the resulting material:

• increased strength in wet conditions;
• compatibility with the entire range of natural and synthetic fibers;
• good and stable dyeability of the fiber, special shine as a result of dyeing;
• environmentally friendly production technology;
• reliability of wearing materials based on this fiber;
• equally effective use in the production of woven and non-woven materials;
• high consumer properties, similar to the properties of cotton fiber, and even exceeding them in strength, quality of dyeing and surface effects;
• tactile effect of natural silk, despite the fact that this fiber is more hygroscopic than natural silk.

The disadvantages include:

• increased fibrillization of fibers, which is removed mainly by formaldehyde agents, which does not always meet sanitary and hygienic standards; on the other hand, reducing fibrillization mechanically or using enzyme treatment increases the cost of fibers;
• high cost of licenses;
• high cost of finished fiber.

Siblon[ | ]

Plant "Sibvolokno"
Siblon - viscose high-modulus fiber (VVM), improved viscose, developed by VNIIIIVproekt. Siblon was invented in the 1970s and was produced at the Sibvolokno plant in the city of Zelenogorsk (Krasnoyarsk Territory) until the early 2000s from coniferous wood. Siblon is approximately one and a half times stronger than viscose, it is more hygroscopic and resistant to alkalis, fabrics made from siblon shrink and wrinkle less[7].

Main production technology

The process of factory production of viscose is a lengthy procedure consisting of several successive stages. And it all starts with the receipt of cellulose at the plant, which has the form of sheets obtained after pre-processing wood chips. The main steps include.

• Preparation and subsequent mercerization of cellulose pulp. This term refers to treatment with a solution of caustic soda followed by rinsing with cold and hot water. This procedure is required to increase the hygroscopicity of the resulting fabric, add shine and subsequent color retention.
• Grinding and pre-ripening. The final point of the previous stage is the production of alkycellulose, which is an alkaline material. It is crushed to obtain a larger surface area. This is required during pre-ripening. It is carried out in special bunkers, where destructuring of molecules occurs under the influence of air.
• Xanthogenation. A chemical procedure during which the resulting composition is treated with carbon disulfide, resulting in the formation of an alkali-soluble compound. When lowered into a weak sodium solution, it is washed out of the future tissue.
• The next stage is to prepare the viscose fabric directly for spinning. This procedure involves mixing viscose from several batches to achieve optimal viscosity, obtaining the desired concentration. Also at this stage, impurities are eliminated and air trapped in the composition in the form of bubbles is removed so that the resulting mass is homogeneous. The threads are also tinted to the desired color.
• Formation. A procedure during which the direct formation of a finished thread occurs through the use of a spinning machine using the technology of pressing through special nozzles and further drawing. This allows you to achieve a material with the desired aggregate properties. During the drawing process, the molecules are ordered along the axis of the fiber, which helps to increase strength.
• Finishing. After formation, the thread is wound onto a special bobbin. But at this stage it is very polluted. It contains mechanical impurities, sulfuric acid, zinc, sodium sulfate. Therefore, processing including washing, bleaching, acidification, desulfurization and oiling is required to improve processing at the weaving stage.
• Drying. The final stage of producing viscose is drying the fiber. At the final stage, the threads are twisted and wound onto bobbins for subsequent sale or weaving.

Cellulose mercerization line

Chemical formula of xanthogenation

After formation, the threads are wound onto bobbins and in this state are sent for drying.

Polynose viscose has increased strength, but requires more effort to produce

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Characteristics of viscose. Advantages and disadvantages

It is not for nothing that viscose enjoys “national” love. Let's look at its advantages.

• Viscose materials differ from most others in their unique property - in summer they give a pleasant feeling of coolness, and in winter they warm.
• Viscose is hypoallergenic and suitable for those with sensitive skin—this plus is also important for parents of small children.
• Tactility, softness and impressive drape make viscose materials a favorite of fashionistas.
• Viscose does not accumulate static electricity, which allows it to be part of multi-layered looks in any season.
• Even at the fiber stage, viscose is easily dyed in any shade. Due to the fact that the dye is introduced directly into the fiber, the brightness and intensity of the coloring is maintained for as long as possible, and the fabrics do not fade.
• Viscose fiber is very light, lighter than cotton. Moreover, the hygroscopicity of this fiber is twice as much as the ability of cotton to absorb water!
• When dry, any viscose fabric is highly durable.

This group of fabrics also has disadvantages, which, however, are significantly less than their advantages.

• When wet, the canvas can be brittle, but this still requires sufficient mechanical stress. Nothing bad will happen to the fabric during normal washing.
• Viscose shrinks up to 10%, but if WTO is carried out in accordance with all the requirements for caring for fabrics made of viscose fiber, then the shrinkage will be less.

Other production technologies

Along with the traditional method of making viscose, which has been used for many years, there are alternative methods. Despite their innovativeness and modernity, they cannot yet be considered universal and are not suitable for mass production.

This includes a method for producing polynose viscose. This is a process that results in a change in structure. During manufacturing, cellulose undergoes a lesser degree of depolymerization, which leads to improved properties of the finished material, in particular strength.

For your information! To produce polynose viscose, purer cellulose and chemical reagents are used

Viscose thread is primarily used to make clothing.

Structure and properties of viscose fibers

The length and thickness of the resulting fibers may vary depending on the prospects for use. In cross section they look like an irregular ribbed circle. From the outside they look like a smooth shiny tube with light strokes along the entire length.

The properties of fibers are usually considered in three aspects.

• Physical characteristics: heat resistance, hygroscopicity, resistance to light, viscose’s ability to swell is excellent.
• Chemical resistance is characterized by experts as average.
• Mechanical characteristics: abrasion ability, strength are not the highest. When wet, the strength decreases even further - by 60%.

Thin viscose threads are used to produce clothing and home textiles. Staple length threads are used to make knitwear, nonwovens, and lace. There is a technical viscose fabric called cordova. It is made from thick viscose threads, intertwined with cotton.

Characteristics and properties

The characteristics of a material are influenced by its manufacturing technology. Therefore, the material has a different appearance. It can be: glossy and matte, textured and smooth, light and dense material.

Is viscose a synthetic or a natural fabric?

Consumers are interested in the question: is viscose synthetic or natural fabric? To understand this issue, you first need to clarify that people produce non-natural material using synthetics. To produce natural material, natural raw materials are used. For example, from sheep wool or silkworm threads. And to make viscose, wood and special chemical solutions are used.

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What is viscose and what does it consist of? It is generally accepted that fabric based on natural raw materials is a natural material.

Properties of viscose, stretches or not

The properties of viscose include the following:

• The material is soft and pleasant to the touch. Folds and drapery look beautiful in sewing products
• Hygroscopic - absorbs moisture well and allows air to pass through.
• Dry material has a high degree of strength, while wet 100% viscose has low strength. To increase strength and wear resistance, manufacturers add chemical additives to raw materials.

The disadvantages, as well as the advantages, in the fabric are compensated by various protective additives. Cotton added to viscose makes the fabric dense and increases its service life. To the question “does viscose wrinkle or not?” easy to answer. The material is strong with an oily sheen. Windbreakers and jackets are made from it. Used as lining material.

Many people are interested in: microviscose - what kind of fabric? If polyester is present in viscose, then the fabric does not wrinkle and retains its beautiful appearance. The elasticity of the material is given by the addition of elastane, which allows the fabric to stretch well.

Appearance of viscose

Flaws

Consumers are interested in whether viscose stretches or not. This fabric is not prone to stretching, but with the addition of elastane it acquires new characteristics. Viscose knitwear is not inferior in elasticity to cotton, but, unfortunately, it also wrinkles.

Viscose becomes deformed and shrinks when washed if the water temperature is high. Long exposure to the sun leads to burnout, and improper care leads to the appearance of pellets. However, these disadvantages are not characteristic of mixed fabrics based on cellulose and polyester fibers.

What is viscose used for?

Viscose is a surprisingly diverse fabric in its manifestations. Therefore, the scope of its application is extremely wide. Of course, the most obvious direction is sewing dresses, skirts, tops and sets from all kinds of variations of dress viscose and staples. Joggers, tiered dresses or long skirts, comfortable tops - all this will work great from comfortable viscose.

Often, costume variations of fabrics are used to create incredibly stylish products suitable for an office wardrobe. The material is affordable, which means it can be safely used for sewing current, seasonal products.

Nonwoven materials for cleaning and raw materials for light industry are also made from viscose. Bamboo viscose is often used in bedding, and even socks.

Composition and processing methods of viscose

The properties of viscose largely depend on the raw materials used for its production. What is it like? There are four main types of fibers obtained from cellulose.

• The most popular, which is made from hardwood of different species, is modal .
• Bamboo can also act as a raw material for future fabric, and bamboo cellulose is very similar in its properties to natural cotton fiber.
• Siblon is a fiber made from recycled softwood pulp. It is very durable, wrinkles little, and does not shrink, but its production has currently been reduced.
• Tencel is made from eucalyptus wood - a material with excellent antiseptic properties, very durable and environmentally friendly.

The technology for producing viscose also affects what the fabric will be like. For example, during processing, threads of different thicknesses are obtained, from which different materials are made. Light clothing materials are made from thin textile threads, and staple fiber (short, uniform length) can even be used to make viscose yarn. Dense, durable viscose threads are used to produce cord materials.

Important physical and mechanical parameters of the fabric - its dullness or shine, density or lightness, texture or smoothness - also depend on the method of spinning the future fiber. So, the original, pure viscose in its characteristics resembles silk, it shimmers, and this shine is removed by adding matting components.

Compound

The composition of viscose 100 contains exclusively cellulose. The structural formula of the organic compound is (C6H10O5)n. Plant polysaccharide is considered one of the most common substances on the planet. Not only viscose fiber is obtained from it, but also paper, plastics, medicines, etc. But what are textiles made of? Wood of different species is suitable for the production of fabric: bamboo, pine needles, eucalyptus. Common varieties of deciduous trees are used more often.

The trained viscose threads are used to make a variety of materials. The weave can be plain, twill and even jacquard. Viscose fabric may also contain other fibers. Fabrics for children's and sportswear include cotton. Fabrics for home textiles consist of polyester. Tight-fitting clothing contains elastane. If the fabric composition includes linen, you get light summer clothes.

Types of viscose fabrics

Conventionally, viscose can be divided into three types: staple fiber, cord thread and viscose silk, and this division depends on the production method and the resulting qualities of the viscose fabric. Staple fiber is mainly used for sewing insulated clothing, blankets and carpets. Cord thread is used for high-quality fabric, and viscose silk is used for sewing bedding (pillowcases, sheets, duvet covers). Depending on the raw materials and the processing technology used, the following types of fabrics are distinguished:

• Tencel . This fabric originates from eucalyptus cellulose. Tencel feels silky and soft to the touch. Has a solid structure. It is used to make both casual clothing and bedding.

Appearance of Tencel fabric.

• Modal . Despite the fact that the fabric consists of 100% cellulose, it has all the qualities of cotton, so you can also sew clothes and bed linen from it. Such properties are achieved through weaving.

Appearance of modal fabric.

• Acetate . Acetate is made from cellulose waste. In appearance, this fabric resembles silk, but this is only in appearance. In fact, acetate is quite fragile, does not allow air to pass through well and practically does not absorb moisture. It is used for lining materials.

The appearance of the fabric is acetate.

• Cupra . The production of this material is not simple, it has its own technological features and difficulties, so it is one of the most valuable and high-quality. Cupra has good breathability, thermoregulation and durability, but it is difficult to care for. It makes great evening wear.

Appearance of cupra fabric.

• Siblon . The fabric is made from cellulose from coniferous trees. It is durable, hardly shrinks or wrinkles, is relatively cheap to produce, and is therefore widely used by consumers. It is mainly used for the production of textile fabrics.

Appearance of siblon fabric.

VISCOSE FIBERS

VISCOSE FIBERS (from Latin viscosus - sticky, viscous), art. fibers formed from viscose - conc. solution of Na-salt of cellulose xanthate in dil. NaOH solution.

Obtaining viscose. The initial raw material for its production is wood cellulose (C.), containing 95-99% high-mol. fiber-forming fraction with a degree of polymerization of 800-1100. Basic stages of the process: obtaining alkaline carbon, synthesis of xanthate, its dissolution, preparation of viscose for molding.

The first stage of the process includes: 1) treatment of the cellulose with 18-20% aqueous solution of NaOH (mercerization) for 5-15 minutes at 45-60 °C and liquid module (the ratio of the volume of the NaOH solution to the mass of the cellulose). ) within 14-40; as a result of mercerization, conditions are created under which r-rime xanthate is obtained; 2) removing excess NaOH solution from the resulting suspension (pulp) using a squeezing press; in this case a product is obtained containing 30-32% C. and 16-17.5% NaOH; 3) grinding of alkaline carbon; 4) oxidize. destruction (pre-ripening) of alkaline color under the influence of O2 air to a degree of polymerization of 400-600. The productivity of the installations is 25-50 t/day.

Xanthate is formed from alkaline carbon as a result of the following reaction:

(x = 0.45-0.65). The amount of CS2 is 28-50% of the mass of C.; up to 30% of CS2 is spent on side processes, which can be expressed by the total equation:

When interacting Na2CS3 with NaOH and O2 air forms a complex mixture of sulfur compounds. Na (sulfide, polysulfide, sulfite, thiosulfate, etc.).

Due to the toxicity and explosiveness of CS2, the process is carried out in sealed apparatus (xanthogenators) with a capacity of approx. 30 m3 at vacuum and in N2 environment. The duration of the treatment is 60-90 minutes, its initial temperature is 22-26°C, the final temperature is 28-35°C.

Tech. C. xanthate is a lumpy orange mass. To dissolve it, dilute is added to the xanthogenator. alkali solution, the resulting pulp is passed through dispersing devices and discharged into an apparatus with a vertical stirrer (the so-called solvent). The duration of dissolution (usually 2-2.5 hours at 12-20°C) and the quality of viscose depend on the degree of grinding of xanthate particles (their size should not exceed 3 mm).

Viscose obtained as a result of dissolving xanthate is an orange transparent liquid with a viscosity of 4-30 Pa*s. Its composition (% by weight): C.-6-10, NaOH-5-7, sulfur compounds. - 3.5-4, water - 80-85. Viscose also contains 0.01-0.02% of dispersed impurities that enter the solution from the raw material, as well as dispersed and dissolved air (10-15 and 0.8-1.0% by volume, respectively). Air is removed to a residual content of 0.15-0.3%, impurities are filtered out.

FORMING CONDITIONS AND PROPERTIES OF VISCOSE FIBERS

When preparing viscose for molding, changes occur in its chemical properties. composition (ripening): xanthate groups are distributed more evenly in the macromolecule of chlorine (this causes a decrease in the viscose viscose by 10-15%), the degree of substitution of viscose and the amount of free NaOH and CS2 decrease, the content of by-product sulfur compounds increases, and stability decreases to coagulation, etc.

Fiber forming. Viscose fibers are wet-spun through spinnerets with a hole diameter of 40-100 microns. Precipitation bath is an aqueous solution containing H2SO4, ZnSO4 and Na2SO4 (see table). When molding staple fiber, the number of holes in the die is 10,000-120,000, textile and technical. threads - resp. 12-100 and 720-2200. The jets coming out of the die are deposited (coagulated) due to the neutralization of alkali, the formation of zinc-xanthate bonds and the desolvation effect of electrolytes, especially Na2SO4. Introduction of modifiers into viscose and (or) into the precipitation bath, for example. polyethylene oxide, helps to obtain fibers of a homogeneous structure (in the cross section of fibers obtained without a modifier, the shell and core can be distinguished). Freshly spun viscose fibers are a hydrated cellulose gel containing up to 80% water.

Staple fiber is formed on continuous units with a capacity of 25-60 t/day. The bundles of threads coming out of the precipitation bath are taken onto spinning disks, from where they are collected into a common bundle shaped like a tape. The tow, passed through a water plasticizing bath with a temperature of 95 ° C, containing 1-2% H2SO4 and up to 1.5% ZnSO4, is taken to the drawing rollers. In this case, the xanthate finally decomposes (the so-called post-reduction of C.), CS2 is distilled off, and orientation drawing and thermal fixation of the fiber occur. Final operations: cutting the strands into pieces (staples) 36-80 mm long, treating the fibers with live steam, washing with water, removing sulfur using a diluent. NaOH solution, bleaching with NaCIO or H2O2, priming treatment, loosening, drying, packaging.

Textile threads are produced on periodic machines. actions. The thread, formed and drawn between the spinning discs, is taken to a centrifuge rotating at a frequency of 8000 s-1. In the basket (mug) of the centrifuge, a “cake” weighing 0.8-1.2 kg is formed. “Easter cakes” are collected in bags, washed, trimmed, dried and rewound onto reels weighing 2-3 kg, which are sent to the consumer.

Tech. threads that do not require a full finishing cycle are usually produced on vertical or horizontal continuous machines. When using machines of the first type, additional restoration, washing, auxiliary processing and drying are carried out on paired rotating rollers with a non-parallel arrangement of axes, which determines the spiral movement of the thread. When horizontal machines are used, the threads are processed in 3-5 troughs installed in series and dried on drums.

Properties of fibers. Viscose fibers are hygroscopic and resistant to most organic compounds. r-solvents, sol. in DMSO in the presence. formaldehyde, in DMF - in the presence. N2O4, in quaternary ammonium bases, etc. They are destroyed in conc. mineral compounds, alkali solutions, oxidizing agents, under the influence of aerobic and anaerobic bacteria, fungi, termites, but not susceptible to moths. When heated (180-200°C) and exposure to UV rays, viscose fibers are destroyed and easily ignite at 180°C. Viscose fibers are usually dyed in bulk (with cubesols, organic pigments, etc.; see Dyeing of fibers).

Disadvantages of viscose fibers that limit the use of staple fiber in a mixture with cotton: relatively low strength, significant loss of strength when wet (up to 55%), large shrinkage of fabrics (up to 16%). Cotton-like staple viscose fibers - high-modulus and polynose - do not have these disadvantages.

High-modulus fiber (Siblon, Avral, Win-Cel, Lenzing-333) is 1.6 times stronger than regular staple fiber, 2 times stronger in the wet state (2.5-3 times more elastic modulus), and resistant to alkalis and oxidizing agents. This improvement in quality is achieved through the use of high qualities. raw materials, increasing the amount of CS2 during xanthogenation, using modifiers, using viscose with a lower C content, reducing the spinning speed, increasing the ZnSO4 content in the precipitation bath and greater elongation of the formed fibers.

Polynose fiber, which is even closer to cotton in strength and fatigue characteristics than high-modulus fiber, has greater fragility. Its production technology is more complex than conventional staple and high-modulus, as it is associated with the processing of high-viscosity viscose and the use of large quantities of CS2.

To obtain fabrics with improved properties (for example, drapability, dyeability), staple fibers are sometimes given crimp or porosity. The first is achieved by drawing and subsequent shrinkage of fibers with an asymmetrical cross-section, the second by introducing 3-5% Na2CO3 into viscose, which decomposes upon neutralization with the release of CO2, which serves as a porogen. Hygroscopicity of fibers m. improved by carboxylation, ethoxylation, and grafting with acrylic acid.

Application of fibers. Regular staple viscose fiber is added to synthetic fibers. fibers to improve sanitary and hygienic conditions. St. products, for cotton (up to 10%) - to reduce thread breakage during spinning. In its pure form it is used in the production of staple fabrics and honey. cotton wool (in the latter case, the fiber is subjected to more thorough finishing and mandatory bleaching). From a mixture of cotton with 33-50% high-modulus fiber, fabrics and knitwear are produced that retain the properties of cotton, but are superior to them in dyeability; from a mixture of fine-fiber cotton with polynomous fiber - underwear and shirt fabrics, knitwear.

The production of viscose threads is continuously decreasing. Textile threads used for the manufacture of knitted underwear and lining fabrics are replaced with polyester, technical. threads (mainly cord for tires) - polyamide and other synthetic, superior to viscose in strength and fatigue properties.

World production of viscose fibers is approx. 3.2 million tons/year (1985).

Technol. The process of producing viscose fibers involves the use of large quantities of CS2 and ZnSO4 (respectively 120-400 and 20-120 kg per 1 ton of fiber). This causes severe gas pollution and environmental pollution. Despite the fact that in modern times enterprises have taken a number of measures to capture the released gases, regenerate CS2 (up to 70% of that spent on xanthogenation), capture ZnSO4 from wash water using ion exchange resins, the problem of neutralizing viscose production still remains relevant.

Lit:. Serkov A. T., Viscose fibers, M., 1981; Maslennikov K.N. [et al.], “Chem. fibers", 1981, No. 1, p. 6-13. A. T. Serkov. === Use. literature for the article “VISCOSE FIBERS” : no data

The page “VISCOSE FIBERS” was prepared based on materials from the chemical encyclopedia.

Is viscose better or worse than other fabrics?

It is difficult to compare viscose with other materials - its properties are unique. At the same time, sewers often ask themselves the question: viscose or synthetics? Of course, you need to look at each specific situation, but for sewing clothes and linen, viscose is a great option. There are many mixed fabrics in which viscose can play a leading or supporting role.

It is clear that for summer dresses, sets, and suits it is difficult to find a fabric better than viscose, which would be just as drapey, light and comfortable to wear. If you are thinking about warmer products for the cool season, it is better to focus not on pure viscose, but on mixed options.

How to choose fabric

Viscose is an unusual material. Its origin is considered natural and synthetic. Recycled wood chips are subject to chemical treatment during fabric production. It makes sense to choose viscose for sewing products. It has hypoallergenic, hygroscopic, breathable, hygienic qualities. The material folds beautifully, drapes easily, and has a reasonable price.

Selection of material for garments

For your information! Viscose differs in one interesting feature and quality from other types of fabrics. When wet, it turns into a dense, hard material. After drying it becomes pleasantly tactile.

Notes[ | ]

1. Chronicle of the Klinvolokno enterprise. Part I. Factory "Klinvolokno" - plant No. 507 (1929-1945). Viscose bobbin production
2. Official website of OJSC "GIPROIV" Archived copy dated October 30, 2011 on the Wayback Machine
3. ↑ 1 2 3 Tsvetkov L.A.
   Artificial and synthetic fibers // Reading book on organic chemistry. A manual for students. - M.: Education, 1975. - P. 196-209.
4. Perepelkin K. E. Lyocell fibers based on direct dissolution of cellulose in N-methyl-morpholine-N-oxide: development and prospects Archived copy of December 13, 2009 on the Wayback Machine
5. Gubina S., Stokozenko V. Viscose and lyocell: two incarnations of cellulose // Science and life. No. 1, 2007.
6. Marini M., Firgo G., Able M. Lyocell fiber // Chemical fibers. No. 1, 1996, p. 27-30
7. Nasonova A.
   Siblon: fiber from the Christmas tree // Chemistry and life: magazine. - 1997. - No. 1. - P. 36-37. Archived from the original on March 4, 2021.

Production

What is viscose fabric? The definition can be given as follows: natural fiber obtained artificially. How can these two concepts go together? Yes, very simple! You will understand everything when we tell you what viscose fabric is made from.

The basis of the material is cellulose, a substance found in wood. In principle, this is everything that matter is made of. Thus, answering the question what kind of fabric is viscose, whether it is natural or not, we can answer - completely natural. After all, it is obtained from natural material, and not from oil and gas processing products.

Let's look at the main production steps:

• Raw materials (wood) are cleaned, crushed and pre-treated
• Dissolves and removes excess liquid
• The resulting cellulose mass is pressed through filters and fibers are formed
• Fiber processing - drying, pressing, bleaching, and then dyeing

So, processed viscose - what kind of fabric does it make?

Varieties

Tencel (lyocell)

The cellulose from which this fabric is made is obtained from eucalyptus. The material is silky, very soft, a fiber whose characteristics are closest to cotton.

Pros:

• increased strength;
• excellent hygroscopicity;
• breathability.

Minuses:

• low resistance to deformation.

It is used in the production of clothing, bed linen, and home textiles.

Modal

Consists of 100% wood cellulose, has all the properties of cotton, but in an improved version.

Positive properties of modal:

• one and a half times more hygroscopic than cotton fabric;
• environmental friendliness;
• high wear resistance;
• increased strength.

Modal is usually used in combination with cotton fibers for clothing and bed linen.

Acetate

Read about: acetate fabric: what is it, not synthetic, not natural, but what kind

For production, it is not cellulose in its pure form that is used, but its waste - cellulose acetate. Thin material, slightly shiny, resembles silk in appearance.

Advantages:

• low creasing;
• resistance to deformation;
• dries quickly.

Flaws:

• does not absorb moisture well;
• when exposed to acetone, the fibers dissolve;
• not resistant to high temperatures (melting point is close to 200 degrees).

Acetate silk is often used as lining fabric.

Cupra

It is made from cellulose, consisting of cotton, which is dissolved in a copper-ammonium saline solution. The material is close to silk and is considered the highest quality and most expensive type of viscose.

Advantages:

• ability to thermoregulate;
• excellent breathability;
• strength.

Flaws:

• require special delicate care;
• not environmentally friendly and expensive production process.

Cupra fabrics are used mainly for sewing evening wear. Products made from viscose require careful care, then the product will last a long time and will not lose its positive qualities.

Application area

Suit viscose is suitable for sewing elegant business style items. This is a fairly dense fabric, often monochromatic. Business clothes made of viscose are practical and versatile. The composition often contains wool and acrylic, which insulate the material and make it denser. A jacket and trousers made of viscose, in the same color, will become the basis of a business wardrobe.

A light viscose dress is suitable for summer. Modal has proven itself well. Pants, blouses, shirts, and skirts are made from it. Viscose knitwear is suitable for making dresses, sweaters, turtlenecks, and sweatshirts. Loose viscose dresses, as well as women's trousers and maxi skirts will come in handy in the wardrobe of a woman of any age.

Staple material makes colorful and positive things for the summer. A pleated viscose skirt will complement the look of a young fashionista and a mature woman. In recent years, pleated floor-length models have gained popularity.

Elastic viscose makes stylish women's T-shirts and sportswear. You can replenish your wardrobe with viscose tights and leggings, jackets and jumpers.

Home textiles

Products made from viscose for the home are also diverse. Cellulose with polyesters has found application in the manufacture of curtains and drapes, bedspreads and canopies. Technical material is used for the production of cleaning sponges and cleaning products.

Cotton varieties are used in the production of home clothing. On sale you can find a viscose dressing gown, pajamas or negligees. Women especially like viscose shirts for their lightness, grace, and unsurpassed appearance.

The lining fabric does not allow moisture and air to pass through well, but is smooth and durable. It is used to sew bedspreads and furniture capes, strengthen outerwear, and use it for the interior processing of bags.

Needlework

Viscose thread is suitable for embroidery. It has a glossy finish and fits well into the design. Household items are sewn from the cuts, and toys are made from the fibers. Shiny thread can be used to wrap metal or plastic buckles. Craftswomen crochet wooden beads to make educational toys for children.

If you have a pattern, it will not be difficult to sew a dress or suit. The material is easy to use, drapes well and forms ruffles. Reinforced varieties are suitable for making interior items, and smooth and non-absorbent fabrics will come in handy when you need to sew in a lining or process the back of a product.

Advantages and disadvantages of the material

Viscose is a natural synthetic obtained from wood. Positive qualities of the fabric:

• does not cause allergies;
• pleasant to the body;
• allows air to pass through, allowing the skin to breathe;
• elastic, stretches well, except for 100% viscose;
• durable;
• Resistant to stains.

Disadvantages include difficulties in caring for the products. When washed incorrectly, the fabric becomes deformed and the surface becomes covered with pellets. Frequent washing leads to fading and wear of the material.

When wet, the fabric becomes stiff. In this form it is easy to damage. After washing, things shrink a lot. Using the wrong detergent will cause the fabric to fade.

Cutting and sewing from viscose fabric is not easy. The cuts crumble, and the material itself is mobile, shifting when cutting. When working with the material, it is secured with pins. It is sewn on a machine after preliminary stitching by hand.

When cutting out parts, wide allowances should be made, and the cuts should then be processed with an overlocker. You need to sew things a size larger, as the product shrinks a lot after washing.

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What is viscose?

Very often people ask: “Is viscose a natural fabric or synthetic?” It's time to answer this question. But first, let me clarify that by artificial fiber we mean fiber that was created by man from artificial raw materials, but natural fiber is based on raw materials created by nature, for example, sheep wool or silkworm threads. As you already understood from the history of the origin of viscose, it is obtained from a natural product - wood, but using special chemical solutions, which is why there is a stable expression: “Viscose is an artificial product, but created on the basis of natural raw materials.”

Viscose appearance.

As practice shows, viscose may not consist of 100% wood cellulose, but may have various additives, both synthetic and natural. Therefore, the material directly depends on the composition. For example:

• 100% viscose . It is soft and delicate to the touch, but not durable;

• Viscose with elastane . This composition makes the fabric elastic;

• Viscose with polyester . Makes the fabric very durable;

• Viscose with cotton . This combination adds strength to the fabric, just like with polyester, but does not reduce its environmental qualities.

Types and their properties

Viscose fabrics come in several varieties. 100% viscose looks like silk - with a pleasant shine and delicate surface. Viscose with elastane is an alternative to cotton knitwear. If viscose threads are intertwined with metallized threads, the result is an elegant material for sewing festive clothes.

The types and properties of the canvas have a direct relationship. Let's name the main types of viscose material and their properties:

• without additives - a beautiful fabric with shine, but low strength and vulnerability to ultraviolet radiation. In terms of characteristics, 100% cellulose is inferior to mixed varieties;
• Tencel - the raw material for this type is eucalyptus cellulose. The fabric is incredibly light and breathable. It is used to make bed and underwear;
• Siblon is a material made from softwood cellulose. The properties of such viscose are strength, hygroscopicity, breathability;
• modal - contains cotton, combines the advantages of both types of raw materials. Used for making children's clothing and linen;
• acetate is a budget fabric made from cellulose waste. More often used as a lining, it is not hygroscopic;
• viscose staple – distinguished by a special manufacturing technology. Suitable for sewing dresses and other clothes, also known as dress viscose;
• oil – includes polyester fibers. Plain viscose fabric with polyester is often used for sewing women's clothing. There are canvases with drawings on sale.