Acrylic fibers according to the desired properties during use;
- 1-High tensile acrylic fiber
- 2-Water absorbent acrylic fiber
- 3-Acrylic fiber with different dyeing properties
It is diversified.
Acrylic Fibers with High Tensile Properties
Compared to normal acrylic fibers, an additional stretching is performed during production, and the shrinkage rate (40%) is increased even more. These types of fibers are used for making high-bulk yarn.
high-bulk yarn
The most important feature of acrylic fiber is that the elongation is not durable when given a stretch of 15-30% in heat, and when steamed, it shortens again and takes its old size.
In this way, if the unstretched (40%) and non-stretched (60%) fibers are spun together and steamed after the yarn is made, shortening is observed in the stressed fibers while the others do not.
In unstressed fibers, twists occur due to the shortening of the other and the yarn gains a bulky appearance. This process is called bulking, and the yarns obtained are called high-bulk yarn.
The fabrics made from these have low texture densities, they keep very warm, their touch, appearance and elasticity are very good. Acrylic HB yarns are used instead of wool in knitting. High-volume yarns can be made from filament or staple fiber:
High bulk yarns spun from filament fiber;
They are produced by the formation of curls in each filament and the process of breaking the parallelism of the filaments to each other.
With this process; folds, loops and waves are formed in the thread.
Bulky yarns can be drawn and stretched by taking advantage of shrinkage differences.
The resulting yarns; It is soft, voluminous and fluffy like a feather.
High-bulk yarns made of staple fiber
Spinning can be created by mixing fibers with low and high shrink potential.
During subsequent steaming, dry heat or hot water treatment; The greater shrinkage of the high-tensile fiber causes the yarn to shorten and the low-tensile fiber to gather around the yarn, increasing the yarn bulkiness.
The shortening of the yarn made from high-shrinkage fibers forces the low-shrinkage yarn to form curls. Like this; the diameter of the thread grows and the thread acquires a fluffy appearance.
Water Absorbent Acrylic Fibers
It consists of a porous core like a sponge and a mantle part. Due to the micro-sponge-like interior, they have high water absorption capabilities. Absorbs up to 38% moisture. These types of fibers also have advantages such as rapid and excessive sweat absorption in the sweating body, not decreasing the air permeability of the product since the fibers do not swell when wet, and good warm keeping properties. Light clothing is produced from these fibers because of their low specific gravity.
Dyeing Properties Different Acrylic Fibers
During the production of acrylic fiber, the use of comonomers that do not contain anionic and cationic groups such as vinyl acetate, vinyl chloride, etc., allows the fibers to take dyestuff at lower temperatures and more easily, but the amount of dyestuff taken increases. To improve the dyeing ability with basic dyestuffs; Vinyl or isopropenyl compounds containing anionic groups are preferred as comonomers, and sulfonate or carboxylic acid groups are preferred as anionic groups.
Some of the fibers obtained in this way and their properties are given below:
Most of the fibers produced as Orlon acrylics contain close to 100% polyacrylonitrile. Strength of Orlon filaments, 2.2-2.6 g/denier; Its specific gravity is 1.18. In standard conditions, the amount of moisture absorption is 1.7%. The ironing temperature is 150 °C. Orlon acrylics are produced in various types and numbers. Orlon 42 is produced in the form of staple fiber and knitting yarns are made. Orlon 81 is produced in the form of filaments. Orlon fibers also have staple type Orlon 39, Orlon 37, Orlon 21 types. They are produced as high-bulk. In addition, those produced in the form of bicomponent fibers are known as Orlon Sayelle; It has a curved structure. Orlon type fibers are known by the trade name Dralon in Germany. Orlon acrylics, produced from 100% polyacrylonitrile, contain anionic sulfide or sulfate groups at the polymer chain ends due to peroxide bisulfate and sulfide or sulfate salts used as catalysts during production. For this reason, Orlon acrylics are anionic modified acrylic fibers and can be dyed with + charge-carrying dyes in their solutions.
Acrilan fibers contain 10-15% cationic monomers in their composition. It usually contains 6% vinyl acetate and 6% vinyl pyridine as comonomers. It is produced according to the wet spinning method by using a 20 °C glycerin bath from a 140% solution in dimethyl acetamide. It is produced in staples or filaments. It can be dyed with acid, chrome, direct and metal complex dyestuffs.
- Acrilan 16 in the production of upholstery and drapery,
- In Acrilan 26 carpet yarn production,
- Acrilan 38 is sewing and industrial thread.
used as.
It contains small amounts of methyl methacrylate as a copolymer. Therefore, they carry anionic groups. Since the ratio of anionic groups in the polymer is higher, the affinity for cationic dyestuffs is higher than Orlon acrylics.
Creslan fibers contain acrylamide as a comonomer. Since the structure of the monomer is cationic, this type of acrylic fibers can be dyed with anionic dyestuffs. As these are used in the production of carpet and blanket type material, worsted and straygarn fabrics are produced by mixing them with wool.
Acrylic fiber containing vinyl pyrrolidone as a comonomer is known as Zefran. It is mostly produced as carpet yarn.
lessontextile 
