Due to the tough competition conditions today, the demands for fancy yarns have increased in parallel with the "different product designs" gaining great importance all over the world. Now, designers use fancy yarn as a fashion element in knitted fabrics. Thanks to the use of fancy yarn, “authentic” designs can be produced economically on normal knitting machines, even with simple knitting structures. Since the structure of acrylic fiber, which is a petroleum derivative, is similar to wool. It is used in almost all areas where natural fibers are used.
It has been determined that it is suitable for making fancy yarns because it exhibits physical and chemical behavior like natural fibers against certain effects. Many different fancy yarns with different structures that cannot be compared with normal yarns have been developed in order to obtain fabrics with visual properties. Its usage rate is increasing gradually due to the superior properties it adds. Acrylic can be used as 100%, as well as suitable for melange use by mixing with other raw materials. Fibers produced as endless fibers (tow) can be colored with gel dyeing or continuous tow dyeing systems during production. Tow products are one of the main inputs for mills that make yarn with the camgam and half camgam system. In order to make yarn from tow, the fiber must be brought to a certain dye. This is done in two different ways:
- Cutting the tow with the knife on the drum (CAP FIBER)
- Tow pulling off (TOPS/BUMPS)
Tops is the continuous form of tow tape, which is torn off by applying a certain amount of traction (drawing) in tearing machines called converters and wrapped in a certain form. The fiber cross-section is mostly produced as beans or triangles.
Acrylic fiber is in the group of Polyvinyl Fibers. Polyvinyl fibers are collected in 4 main groups:
- 1-Polyacrylonitrile fibers: Acrylic, modacrylic fibers
- 2-Polyvinyl chloride fibers: 100% PVC fibers, Polyvinyl chloride copolymers, modified polyvinyl chloride fibers
- 3-Polyvinylidene chloride fibers
- 4-Povinylalcohol fibers
Acrylic fiber is the type of fiber most similar to wool among artificial fibers. According to the definitions of ISO (International Standards Organization) and BISFA (International Synthetic Fiber Standardization Office), fibers containing at least 85% acrylonitrile in their chemical structure are called Acrylic fibers.
Due to its similarity to wool among synthetic fibers, it is a fiber used a lot with wool. Its raw material is petroleum. It is produced as a filament, but it is more commonly used by turning it into staple fiber.
The most important feature of acrylic fibers; The reason is that the elongation is not durable since a stretch of 15-30% is given during the production of the yarn, and when steaming is done, it gets shorter again and takes its old size. In this way, if the unstretched and unstretched fibers are spun together and steamed after the yarn is made, shortening is observed in the stressed fibers while the others do not. In unstretched fibers, twists occur due to the shortening of the other and the yarn gains a bulky appearance. The yarn obtained by this process is called high-bulk yarn.
It is suitable for blending with wool, cotton, viscose fibers. They are generally round in cross section and their surfaces are smooth.
Acrylic-cotton mixture; It gains weight and hardness by mixing with acrylic cotton. Cotton provides moisture absorption and strength. It increases crease resistance. Fabrics made with 80% acrylic and 20% cotton are used in sportswear with a wash-and-wear feature.
Acrylic-viscose mixture; It gives crease-free and smoothness to viscose acrylic. It gives different painting effects. For a good wash-and-wear property, the fabric should contain 70% acrylic.
Acrylic-polyester mixture; When acrylic is mixed with polyester, warm fabrics with good wearing comfort are obtained. Wrinkles increase. A 50%-50% mixture provides a good wash-and-wear effect. Such a fabric gains strength from polyester and rubbing fastness from acrylic. However, the pilling risk of these fabrics is high.
Acrylic-nylon mixture; When the superior strength and friction fastness of nylon are combined with the luxurious attitude and coating feature of acrylic, durable fabrics that keep warm are obtained. With the properties of acrylic and nylon close to each other, fabrics with high wearing comfort are obtained.
Acrylic-wool mixture; The main feature of acrylic is that it is fluffy. The fabric to be obtained in the mixture is both light and warm. It can also do some pilling. Such fabrics have low wrinkle resistance and are washable. For a good wash-and-wear property, the mixture should contain at least 60% acrylic. If the acrylic is too much, the fabric will be fluffy. Acrylic wool blend fabrics are more durable than pure wool fabrics.
Its specific gravity is 1.16-1.18 gr/cm3. It is a light fiber. Its moisture absorption value is around 12,5% and it is hydrophobic (does not like water). Acrylic fiber does not absorb water from its surface, it takes it from its cross section. That's why it's mostly used intermittently. Dunova fiber is produced to improve moisture absorbency. In the structure of this fiber, there are pores that can store moisture and water, a spongy structure and voids that will provide absorbency from the surface. Because of these properties, this fiber is used in products such as warm clothes, sweaters and underwear.
The strength of acrylic fiber is between 2,5-4,5 gr/denier. Its strength is reduced by 10-20% in wet condition. It may turn yellow at temperatures above 150°C.
It softens above 105°C. The ironing temperature is around 140°C. Static electricity is high. It has a high heat retention ability, suitable for raising, soft and elastic, resilient, suitable for fixation, shrinkable and voluminous.
In woven and knitted fabrics, it provides a high degree of air retention and gives the ability to retain heat. It prevents felting when mixed with wool with at least 40%.
They do not wrinkle easily and resemble wool with their full, warm, soft handle. Therefore, it is a fiber suitable for the human body. Fabrics containing this fiber are easy to wash and dry quickly due to their low moisture absorption.
Acrylic fiber is resistant to acids. They are not affected much by organic acids and non-concentrated inorganic acids. Although they are resistant to concentrated solutions of hydrochloric acid, they are soluble in concentrated solutions of nitric acid and sulfuric acid.
The basis of synthetic fiber production is that monomers are connected to each other in a straight chain structure.ğof polymers obtained fromşIt is based on turning it into fiber by pulling according to push methods.
Therefore, first of all, polymer production suitable for fiber production should be realized.şIt must be spun and then fibers drawn from these polymers.
Appropriate flux obtained by melting the polymer material either by dissolving it in a suitable solvent or by heating it to temperatures above its melting point.şsolution or solution in the bloodğthrough the nozzles and then this fluxşreincorporation of blood polymerşbased on climbing.
Chemical fiber production
Mainly, it is made by 2 methods as fiber spinning from melt and spinning from solution.
The fiber spinning method from the solution is in itself. dry drawing method orş shooting method is divided into two.
Consist of 100% polyacrylonitrile unitsşan acrylic fibers; It has a tight supramolecular structure due to the effective attraction forces between macromolecules. This tight structure has poor dye uptake.ğscience, long-termşchange their color when exposed to light and heat.ğişin addition to the isalso causes some difficulties in their availability. For these reasons,ğThese commercial acrylic fibers are made of pure acrylonitrile.şmay not have the desired fiber properties andsavailableğsignificantly improve yourşIt contains between 5% and 15% one or more comonomers to make
Form acrylic fibersşTuran polyacrylonitrile polymers are obtained by radical chain polymerization of acrylonitrile monomers. by definitionği Acrylic fibers must contain at least 85% acrylonitrile units.
After the preparation of polyacrylonitrile polymer together with a suitable comonomer, in order to produce fiber from this polymer, first of all, the flux of the obtained polymer for fiber drawing is appropriate.şIt must be turned into a blood-holding solution (dop). Polyacrylonitrile polymer heatedğreach the melting pointşIts structure is deteriorated before processing, but it is suitable for fiber spinning by using suitable solvents.şli fluxşbloody polymer extraction solution can be obtained. For this reason, poly-acrylonitrile fibers can be produced by the solution spinning method. Acrylic fibers both dry ands Although it can be produced by the drawing method, the world's acrylic fiber production is approximatelyş85% of thes with the shooting methodşis being raised.
The prepared draft solution is poured from the nozzles.şafter shrinkage, washing, stretching, preparation, drying, curlingşclimbing and thermalşIt is passed through threads and turned into filament tows. Tow fibers for tearing or cuttingşThe final fibers to be used in textiles are obtained by turning them into staple fibers with the lemi. dry ors All these techniques applied in shooting methodsşThe operations are generally the same, but the process after fiber spinningşsequence of actions or application şconditions may differ slightly.
During fiber production, eachşlem stepğThese are very important factors that affect the properties of the fibers. As a result of these production steps, the fibers are sgets attached. The properties of the fibers are largely the same as what they see in these production steps.şyour realms şto your terms
Coagulation, flow from nozzlesşRemove the solvent to a large extent from the crushed polymer solution.şscratched into a gel fiberşderivation işlem. eithers In the drawing method, the nozzle system is immersed in a liquid bath containing coagulant.şTruck. The coagulant used in the coagulation bath consists of a solvent (solvent) and a non-solvent (non-solvent).şmoment is a solution. In the coagulation bath, the same solvent used in the preparation of the polymer extraction solution is generally used as the solvent and water is used as the non-solvent.
The polymer solution is pumped into this nozzle system and a very fine spray from the nozzles into this coagulation bath.ssproutsşis broken. Join fibers hereşThe arach becomes a gel fiber. Coagulation bath, first fiberşmake your hope come trueştiğalmostsbutt and fiber propertiesşplays a very important role in the In the coagulation bath, the polymer material turns into a gel-like fiber, the solvent and the non-solvent are mixed together.şin a warm placeğişperform withşis working. In the coagulation bath, the polymer/solvent/non-solvent may interact.şbookmark andğişAs a result of the formation of imprints, a fibrous structure is formed.şarachnid fiber şbeing planted andğişacquires features.
First i after coagulationşlem wash işlem. It's actually a diffusionşlem. Filaments coming out of the coagulation bath; It still contains a large amount of solvent on it. Thanks to the concentration difference, the water in the washing bath and the solvent in the fiber are mixed.ğişthe majority of the solvent in the fiberğa luğu is resolved.
washing işmore than oneşcome trueşand the reverse current principle is used. next işconvenience in affairsğA small amount of solvent is left on the filament to bind. After washing, the filament retains its porous structure. The next i of the fibersşin threads and fabricsş production aşbut i'm betterswashing or stretchingşalso after theğişTwo finishing agents are added. Solution
These substances added as emulsions are usually eitherğThey are substances with astringent and antistatic properties.
Orientation or Stretching BusinessLemi
this işlem fiber structureğişImprove fiber properties by shavingşhung upğIt is very important for me. filament hotğı, glassy transition around 65 – 70 ºC using hot waterş hotğis raised above it. and between the rollers rotating at different speeds, generally 3 to 12 times stretching is done. In this stretching process, the fibers are formed in the drawing bath.şThe orientation of the fibrous structure increases, thereby increasing the fiber strength.
Before or after washingşHowever, a chemical substance is applied to the fibers. This chemical or preparation agent is normally in the form of an aqueous solution or emulsion, and in both cases static electricity is generated in later stages by fiber-fiber and fiber-metal friction.şwill reduce the hope, the fiber will become aşwill assist the process by preventing overheating orğlickers, softşContains scavengers and antistatic agents. The type and amount of preparation agent used is critical for downstream processing and fiber performance. Depending on end useğAs a result, the amount of preparation on the fiber can be 0,1 – 0,7%.
These phasesğişik şcan occur in rows and rows. drying işlem, heated fibersş It is made by passing it through a region or over hot drying cylinders. drying işprevious production on lemi fiberşget rid of the remaining water from their buttsşit is dried by scratching. Here, remove the remaining water on the fiber.şscratching as well as the fibrillar ağwater contained inşAs the bee leaves, the pores in the fiber structure also collapse and shrink considerably. The collapse of the fiber pores causes the fiber structure to become oriented due to the draft bath.ş is the closure of open pores. crash işIt is also an event that occurs only during drying.ğyear. with curlyşclimbing and temperingşThere is also some subsidence in the earth.
with curlyşclimbing išLemi
with curlyşclimbing işOperation is a mechanical Operation and thisşlem usually with curlyşIt is done with a scratch box. with curlyşclimbing işThe purpose of the yarn is to give cohesion and bulkiness to the fiber bundle, which contains many fibers. Because the amount of crimping of staple fibers affects their performance both during yarn production and use.
Fixing (Annealing) BusinessLemi
fixation işWith the film, both the collapse of the fiber pores are completed and the relaxation of the fibers.şsuck it upğit is lit. TOğIf the collapse is not completed, the fiber collapses.ş and the open one doesn't crashş There is a difference in fragility and brightness between regions. desired each production step of the fiber production line, in order to produce fibers withğIn addition, the physical, chemical and internal structure occurring in the fibers are alsoğişvery well known and accordinglyşlem şSetting the conditions is very important.
Physical Properties of Acrylic Fibersi
Cross section and longitudinal view: Age width of acrylic fibers produced according to the spinning methode-section round or bean sis attached. Acrylic fiber obtained according to the dry spinning methodcross section of peanutsis attached. round vo beansacrylic fibers with cross-section springiness, peanut şwith cross-section The softness and brightness of acrylic fibers are also good. Longitudinal view of acrylic fibersplumsmooth, twisted and striped.
İprecedence and length: Types of acrylic fibersIt can be produced in lengths. It can be in filament form depending on the usage area.as you know, staplemay also be attached. In order for the fibers to be used as staple (staple) to be more voluminous, they are folded.
Strength: The strength of acrylic fibers is not as high as other synthetic fibers (nylon, polyester, olefi). It is more close to natural fibers such as cotton wool fiber. Strength of acrylic fibers 2 – 3,6 gr/denier.
Moisture absorption: Acrylic lThey have low moisture absorption property. This rate varies between 1% and 2,6% under normal conditions.is working. acrylic ldecrease in moisture absorptionhigh, water on the surfaces of the microfibres It has high holding properties.
against frictionI durability: Akrylic fibers against frictionı durability is not good.
change sizetackiness: The size of acrylic fibersuntiringi am not good. hot fix jobapplied polyesterchange in the size of the fibersthere is no difference. Vapor acrylic productsmay cause changes in their swallowing.
Flexibility and springiness: The flexibility of acrylic fibers lower than synthetic fibersthank you. The springiness varies from good to very good according to the type of fiber. elongation of acrylic fibersa rate varies between 20 – 36%i.
Elongate acrylic fiber by 1%It can stretch 95% when pulled.
Volumetric density: Specific gravity of acrylic fibers Varies between 1,14–1,19 gr/cm³Inhibitory.
Chemical Properties of Acrylic Fibers
Being affected by chemicals: Acrylic fibers are resistant to acids other than nitric acid.I is durable. Especially dense and hot alkalis damage the fiber. In dry cleaningSolvents used to harden the fiberroad to her breast can open. chlorine bleach externalto the bleaches init is durable.
Against environmental factorsI durability: Resistant to sunlight of acrylic fibersIts durability is quite good. Bacteria, fungus, mold, moth and other harmful insects do not damage the fibers. Electrification property: Electricity conduction of acrylic fibers because it absorbs less moisturethank you. For this reason, static in acrylic products electrification problem.
Ability to be affected by heat: Acrylic fibers do not have a certain melting point. melting pointchange the bowl between 215 – 255 °Cir. very high temperatureclicks change color of productscan cause dichotomy. Ironing temperature should be 110 °C.
Combustion feature: Flame encounter of acrylic fibersit melts and burns. It continues to burn after the flame is removed. A chemical smell and a black is leaves. The ash is hard, black andit is uncultivated.
End Uses of Acrylic Fiber Clothes: Sweatshirts, socks, plush, circular knit, sportswear and children's wear Home textiles: Carpet, blanket, rug, upholstery, velvet fabrics Outdoor use: Car ceilings, boat covers, tarpaulin, outdoor furniture
Industrial usage areas: Dust filter, reinforcement filler in construction construction, car batteries