PET polyester, chemically named polyethyleneterephthalate, was discovered by Whinfield and Dickson and was first produced on a commercial scale in 1941.
After the Second World War, ICI firm in England and DuPont firm in USA developed polyester fiber production methods. Especially since 1950, there has been a rapid increase in polyester fiber production. It is one of the most produced and consumed fibers among synthetic fibers.
Polyester fiber produced from polyethyleneterephthalate, a derivative of the petroleum industry, by the process of drawing fiber from the melt, is a very important fiber. Although it was not used much at first, its use became widespread and further developed over time. As the fiber itself has been developed, the dyeability properties of the fiber and new dyeing methods have also been developed. Polyester fibers can be used alone as well as with other natural and artificial fibers.
Polyester fiber mainly; It can be characterized by its hydrophobicity, high strength, non-crease. With these features, polyester fiber; It is an important fiber type that plays a role in improving the usage properties in cotton, viscose and wool blends.
polyester fiberının physical properties
- Its longitudinal section is smooth and uniform, with a rod-like appearance. Its cross section was mostly round. It has different sections according to its flat form.
- When they are first produced, they are in the form of endless filaments. They can then be cut into desired lengths as staples.
- Fineness in synthetic fiber is as desired during production.
- Specific gravity 1,38 g/cm³
- It is white in production. If desired, colored fibers can be obtained by adding pigment colorants to the fiber drawing solution.
- It was glossy in production. If desired, it can be mattified by adding matting agents to the fiber drawing melt or later by various processes.
- Under normal conditions, the humidity is 0.4%, it can be described as hydrophobic.
- It has good and excellent strength. Dry strength varies between 4.5-8 gr/denier depending on the production method, monomers and stretching amount. There is not much difference between dry strength and wet strength.
- Elongation elasticity is moderate or good. Stretching abilities were between 15-30% in normal filament fiber and 30-50% in staple fiber.
- The resilience (spring) is excellent. It recovers well without crumpling.
- It starts to soften at 130ºC and begins to melt at 255-260ºC.
- There was a static electricity problem due to its low moisture absorbency.
- Pilling is mostly seen in polyester fiber among textile fibers.
Chemical properties of polyester fibers
- It is resistant to dilute acids both in hot and cold temperatures, and to concentrated acids (except sulfuric acid) only in cold weather.
- It is cold resistant to alkalis. It is affected even by weak alkalis at medium and high temperatures.
- It has a high resistance to oxidizing and reducing substances.
- It is resistant to most organic solvents. It is not damaged by solvents such as benzene, trichloroethylene, carbon tetrachloride, perchlorethylene used in dry cleaning. They are completely soluble under certain conditions in some solvents such as odichlorobenzene and dimethylterephthalate. The swelling effect of organic solvents facilitates dyeing of polyester.
- It shows high resistance to light and atmospheric conditions.
Polyester has many uses in textiles, both as a continuous filament and as a staple fiber. It is an important fiber in the manufacture of many products used in ready-to-wear, home furnishing and industrial areas. It is also important in areas that require resistance to outdoor conditions. It is used by mixing with wool for light and thin fabrics, clothes that require permanent ironing, knitted outerwear and heavy fabrics such as suits. It is generally used in the production of raincoat and shirting fabrics by mixing with cotton at a rate of 35% or 50%. It has an important use in the production of staple, filament and core threads for sewing threads. Polyester fiber is not used in hosiery, as the fiber does not easily stretch with light loads.
Viscose is the first regenerated fiber and is a non-synthetic man-made fiber. Its raw material is produced from wood pulp, which contains natural cellulose. For this reason, it is more similar to natural cellulosic fibers such as cotton and linen compared to synthetic and thermoplastic fibers such as polyester and nylon.
Although viscose is obtained from wood pulp, which is a cheap and renewable resource, it causes intense water and energy consumption during its production and also contributes to air and water pollution. Production with readily available raw materials ve With the modernization of processes, viscose increases its competitiveness in the market.
Until the end of 1664, the English naturalist Robert Hooke envisioned that artificial fibers would be produced in the same way that the silkworm produces silk. In the future, many scientists have worked on this subject, but they have not been successful.
In 1855, the Frenchman George Audemars obtained thread by inserting a needle into a dense solution of mulberry bark pulp and gum rubber. However, such a production required considerable attention. Therefore, production is slow and causes high costs. Shortly after, in 1891, English chemist Charle Frederick Cross and his colleagues Edward John Beyan and Clayton Beadle invented the viscose production process. The raw material of viscose fibers is cellulose. Cotton linter and wood cellulose containing 92-98% cellulose are used for production. After cleaning these substances, alkali cellulose is formed by treating them with caustic soda.
It goes through a mechanical press to remove excess caustic in alkali cellulose, then through a mechanical cracker to increase the impact surface. The cellulose is then converted to xanthate by treatment with carbon disulfide and dissolved with a dilute caustic soda solution.
After the crude viscose solution obtained is subjected to the curing process, it is drawn in acid coagulation baths and thus viscous filaments are formed. During viscose fiber spinning, fiber spinning is done in a vacuum environment so that air bubbles do not cause breakage of the fiber coming out of the nozzle. It is also passed through a coagulation bath to prevent the filament from sticking. After the fibers are produced, they go through the stretching process. Stretching takes place in two steps.
A 10% tension is applied in the first step, while a 50% tension is applied in the second zone. Then the fibers, which are turned into tows, pass through a second bath and go to cutting. After the cutting made here, viscose fiber is produced. Yarns obtained from regenerated cellulose fiber in filament form are called floss (rayon), and yarns obtained from staple fiber are called viscose yarns. In filament yarns (flush), features such as appearance, touch and shine are silk-like, soft and draped, they do not cause problems in terms of static electricity and piling. Yarns made from staple fibers (viscose), on the other hand, exhibit moisture-absorbing properties similar to cotton to a large extent. Its strength is less than filament yarn. Apart from this, its properties can be improved even more with various finishing processes that are similar to each other.
Physical properties of viscose fibers şu şis planted,
- The fiber has many channels running along its length and these correspond to the notches that are a feature of the cross section.
- The fineness of viscose fiber is expressed in denier. Viscose fiber is generally produced as 1.5-2.5 and 3.75 denier.
- Its specific gravity is 1,15g/cm³.
- Age strength; l.2-1.7 g/denier, dry strength; It is 2.3-3.0 gr/denier.
- In case the force applied to the viscose fiber is within the elastic limit; It was determined that it elongated by 10-23% as dry and 16-33% as wet.
- Viscose fiber has high moisture absorption due to its structure. The fiber absorbs a significant amount of moisture from the air. Commercially, the humidity value of viscose is 13%.
- Viscose has a unique shiny appearance. Some amount of light is absorbed as it falls on the fiber. The reflected light is white. Most of the light is reflected from the smooth and regular surfaces of the filament or staple fibres, resulting in a dazzling and radiant shine. Therefore, a matting agent can be added to the fiber spinning solution.
- Withstands heat up to 115ºC, then turns yellow and burns leaving whitish ash.
- The influence of light is significant. The moisture content of viscose increases the effect of light and the value of its strength decreases.
- If viscose is exposed to drying, its strength decreases and color fading occurs.
The chemical properties of viscose fibers are as follows;
- Dilute acids act after a certain temperature, while pure acids act at cold.
- It is durable, just like cotton, in direct proportion to the concentration of alkalis and temperature.
Flush-viscose yarns in filament or staple form have a wide use in woven and knitted fabrics. Finely draped and fancy fabrics can be obtained, displaying most of the yarn properties in the same way. Viscose fabrics are also suitable for processes such as dye printing.
Viscose fiber has a very wide usage. It is used in ready-to-wear products such as dresses, jackets, swimwear, home textiles (such as bedspreads, sheets, curtains, tablecloths), industrial products, and medical products. They are especially common in the production of stylish and flowy fancy clothes. It is also used as a lining in upper clothing.
Fiber types with high extensibility can be defined as elastomer fibers. Elastomer fibers are fibers that can show very high elongation without breaking due to their chemical structure and can fully and quickly recover at elongation up to breaking point.
According to international conventions, the polyurethane elastomer fiber called “Elastane Fiber” not only has high flexibility, but also has a very high tear resistance. Therefore, it provides ease of use in many areas.
The basis of polyurethane-based elastomeric fiber synthesis is based on the diisocyanate-polyaddition process developed by Otto Bayer, H.Rinke et al. in 1937.
The first industrial polyurethane-based elastomeric fiber production was carried out by JCShvers et al. in the research departments of DuPont company by dry spinning process. DuPont company has been producing this polyurethane-based multi-filament elastomeric fiber since 1962 under the name Lycra. According to the definition made by the American Federal Trade Commission, it is a synthetic polymerization chain that contains at least 85% segmented polyurethane. “Spandex” name is given.
Due to the widespread use of polyurethane group fibers, especially in America and Canada “Spandex” is used as the general name of elastomeric fibers.
if in Europe It is seen that the general name of polyurethane-based elastomeric fibers is "Elastane".
Elastane fiber is produced in infinite lengths as mono or multi filaments. If desired, it can be made intermittent (stapel) according to the place of use. Today, it is possible to find elastane in the industry with a fineness ranging from 11-2600 dtex.
Physical properties of elastane fibers şu şis in cultivation;
- Their cross-sections differ according to the production methods. It can be round, oval, rectangular and similar shapes. It was usually round
- Its density varies between 1,15-1,95 g/cm3 depending on the type of elastane and production method.
- Elastane fiber is produced as transparent, matte and glossy in color.
- The maximum elongation limits of the fiber and the resulting maximum breaking force play an important role in the functionality of the finished product.
- It was less durable than other synthetic fibers. Their strength varies between 0,5 - 1,5 g/denier. Age robustness shows little decline.
- Its dehumidification feature is very low as it is a hydrophobic fiber. At 65% relative humidity and 20% humidity at 1º C, it is not affected by water much.
- Depending on the types, their resistance to temperature changes and hardening occurs at 150º C. It softens between 150-200º C and melts between 230-290º C. The ironing temperature should not exceed 150º C. High temperatures cause fiber degradation.
- It melts and burns. Gives off chemical odor. It burns without.
- Static electricity medium Static electricity may occur in a dry environment.
- Sunlight causes yellowing and damage to the fiber.
When certain chemicals are applied to elastane fabrics, they can damage the elastane fibers in the fabric. Elastans are affected by unsaturated oils and greases. Their colors fade and disintegrate. The raw fabric containing elastane, which needs to be stored in extended time intervals, should be washed and rinsed with plenty of water to prevent it from rotting from discoloration and unsaturated oils. Chlorine-releasing chemicals will also fade and deteriorate elastic threads. Chlorine in swimming pool water gradually weakens the elastic threads in swimsuits and causes them to break after a while. Prolonged exposure to ultraviolet rays creates the same effect. air pollutedği and climate is differentılıclearıdue toı In addition, fading and yellowing increase in elastane fibers andıklılLIGHT decliningır.
While yellowing does not affect the elastane's wear performance, the fabric or display garments lose customer appeal. To prevent this all warehouse clothes and sandşThey should be stored in chemically inert and airtight packages.ıdır.
Chemical properties of elastane fibers şit is;
- It is resistant to most acids unless exposed to more than 24 hours. They do not suffer much damage from aqueous acids in the cold. In the heat it all affects them more or less. It decomposes and dissolves readily in concentrated mineral acids.
- It is resistant to most bases. It shows a decrease in its physical properties in dilute cold processes. For this reason, the physical properties of caustic products should be controlled.
- It is resistant to dry cleaning solvents. Skewer in aromatic solvents
- Chlorine bleaching, such as sodium hypochlorite, should be avoided. Chlorine oxidizing substances cause color change and decrease in physical properties.
- It is not affected by mold and fungus, moths and insects.
- It can be dyed with disperse, acid, metal-complex, chroming dyes. Some types are difficult to paint.
Elastic threads and fabrics have an important place in the world textile industry. Among the fashion trends exhibited in the 2000s, there is almost no design without elastane. Elastane clothing has an important place thanks to its comfort and functionality. The emergence of new products has been ensured by the replacement of natural rubber and rubber in textiles with elastane. Comfort, usefulness and versatility in clothing have become more and more sought-after features.
Among the classical usage areas of elastane textile products men and women socksı, underwear, swimming wear, corset andğsoonerıbbı textiles are available. In recent years, the production of textile products containing elastane yarn has shown great increases compared to previous years. In addition to fashion trends, the increasing demand for more comfortable, useful, versatile and functional textile products has also been effective in this. These developments have enabled the use of elastane textile products in a wider area than classical areas, from leisure wear, sportswear and gymnastics to men's and women's wear. For sports that involve a lot of activity and require high range of body movements, the stretching ability of the fabric should be 35-50%.
Due to the very high elasticity and resilience (springing) ability of elastane yarns, even at low usage rates such as 3-5%, they provide important properties other than elasticity to the fabric and clothing. It is possible to list these features as follows;
- A neater and more pleasant appearance in clothes,
- Increase in clothing comfort,
- The shape dimensions (body measurements) given to the clothes are more permanent,
- High degree of elasticity, less wrinkling tendency,
- As a wash-wear effect
Elastic textiles, cotton, wool, polyester, polyamide, acrylic, etc. It is obtained by weaving or knitting classical textile fibers with low percentage of elastane yarns. The usage areas of elastane yarns and elastane fiber ratios are shown below. Except for swimming suits and medical textiles, the usage rates of elastane yarns in fabric are generally below 10%.
Elastane threads are compatible with the fashion factor and contribute a lot to fashion. Because it is used in every field, it adapts to different styles and trends today. It is less affected by water and maintains its elasticity for a long time. Today, elastane is in the content of almost all kinds of clothes and outfits. Elastane is used in every field from daily wear to sea wear, from sportswear to classic wear, from blue jeans to evening wear.
GENERAL PROPERTIES OF PES/VIS/EA BLEND YARN
Yarns that contain dissimilar components in their structure, especially in terms of fibers and filaments, are called blended or combined yarns. Blend fiber is obtained by combining two or more fibers.
Blending has been done since yarn production and surface formation. Other benefits are gained with the mixture besides improved quality and reduced cost.
Ancient spinners “spinner's artı snowheatit is hidden in myheatmın the importance of a nice şhighlight in the cropbusinessbaconır.
Today, the fiber blend is considered a combination of science and art.
fiber snowheatDo you haveı çaşdo it for purposeılır. These purposesworku şin the plantıwe can rave;
- A uniformly distributed raw material is obtained with the mixture.
- As a result of the homogeneous distribution of raw materials from different sources in the yarn, the quality of the product produced is increased.
- The good properties of the blended components are utilized (For example, the durability and easy-care properties of polyester are used in the polyester/viscose mixture.) It can affect the touch, brightness, color, etc. by selecting the appropriate fiber fineness and length.
- Instead of some of the expensive natural fibers, artificial fibers are used, which are quite cheap (For example, wool / viscose)
- Smooth, glossy-matt fibers or fiber blends should be used in accordance with the place and purpose of use.
- Fashionable effects can be gained by using fiber types or types with different properties.
- For example; such as heat insulation, handling properties, moisture absorption properties.
- Blended structure in order to improve the care properties of yarn, fabric obtained from yarn and final product.
Features such as washing, drying and ironing are improved in textile products.
The benefits of using artificial fiber in the mixture are lower surface weight, easier maintenance (wash-wear), and very easy sewing for certain article groups, as well as reducing costs. With the introduction of high-volume fibers into production, a voluminous, soft, hairy upper surface has been gained in woven and knitted fabrics.
The mixture of natural fibers and artificial fibers is mostly made in order to increase the use value. The mixture has a special place in terms of ease of use and hygiene.
Another reason to use fiber blends is fashion. Special effect yarns are made by working with triple or more multiple blends. This effect can be increased by choosing the mixing components in different finenesses and colors.
Since the purpose of the blend is to bring together the advantageous properties of the fibers, to combine them with one another and to close or reduce the undesirable properties of each other, the "optimal blend" emerges.
The properties of the same type of product produced at different mixing ratios also vary. In order to determine between which fibers and in what proportions the optimal mixture is, first of all, the expected properties of the product should be known.
Based on what is known, the appropriate fiber selection is made. It is calculated which fiber should be mixed with which fibers and in how much. After all these are done, the technological feasibility of production is investigated.
The arrangement of the fibers in the blend yarn has a great influence on the finished surface (product) character. While the fibers located close to the center have a subjective effect, their features such as the appearance and touch that dominate the outer surface come to the fore.
Studies have shown that in blended yarn, short or coarse fibers are located on the outer surface of the yarn, long or fine fibers are located in the center and in the yarn core.
Two important criteria in fiber selection in blends are economy and quality. In addition to the fiber properties, the properties of the yarn produced are also the factors that affect the mixture. Especially the touch, volume, appearance and strength are closely related to the yarn production system used.
a snowheatm cordğget downşhope the most importantğrules of thumbworku şis in cultivation;
- The fiber fineness limits the spinnability of the yarn. In order to obtain a useful yarn, there is a minimum number of fibers in the yarn cross-section. This is particularly important in rotor spinning. In order to increase the spinning limit, it is necessary to use finer micronaire or microfiber of synthetic origin.
- When mixing fibers of different fineness, care must be taken to ensure that the mixture is as homogeneous as possible, as if mixing fiber lots of the same different colors. If this is not done or if one of the components is too low, the components will separate instead of mixing, which will not only cause errors and irregularities, but also cause results that are contrary to the specifications expected from the yarn.
- Another criterion related to fiber blends is the strength/elasticity curve relationship.
Mixtures commonly used in textiles;
Polyester/cotton, polyester/viscose, polyester/wool, wool/polyamide, wool/viscose şis attached.
Viscose fibers, unlike polyester, can contain 40-80% water in their structure, thus keeping humidity under control. It makes the skin feel dry. In addition, the softness and brightness of viscose are used.