Rayon is the general name given to regenerated cellulosic fibers. Among all fibers, rayon continues to be the fiber that most confuses and attracts consumers, as it can be used in a wide variety of fields and has the characteristics of both natural fibers and synthetic fibers. Rayon can be used as a substitute for cotton fiber in many places, and it is used in the clothing industry, home textiles and industry in a wide range from absorbent hygiene products to baby pads and high-strength cord fabrics.
Rayon is the first fiber ever produced. It was developed in France during a research covering the general properties of cellulose in the 1890s and was called "artificial silk" (artificial silk) in those years because it resembles silk.. In 1924, this fiber was given the name "rayon" meaning "rays of light" by the textile industry. The most important feature is that it is not synthetic like other man-made fibers. It is produced from cellulosic-based cotton linters or wood pulp obtained from spruce wood. As a result of this, The properties of rayon fiber resemble natural cellulosic fibers such as cotton and linen rather than synthetic fibers such as nylon and polyester. The wide variety of uses of rayon as a fiber, its lower cost compared to cotton and its superior comfort properties have made its usage area quite widespread.
Classification of rayon
Due to the structure of rayon fiber, it has the characteristics of natural and synthetic fibers, making it a widely used fiber recently. Rayon can be used as a mixture with finely drawn synthetic filaments, as well as in the form of staple fiber, which is folded and cut into 6 - 20 cm lengths.
When evaluated in terms of product performance, rayon can be classified under four headings. Among them, normal rayon (viscose) and high strength rayon constitute two important groups.
1. Normal rayon (viscose):
Viscose to cut rayon fibers used in mixture with staple fibers (cotton, wool) is named. It is the rayon type with the highest market share. It is used in ready-made clothing and home textiles and is referred to as "viscose" in the washing instructions. Its distinguishing feature is its very low wet strength. As a result, it becomes unstable and shrinks or releases when wet. Dry cleaning or very delicate hand washing is generally recommended to preserve the appearance and functional properties of fabrics made from this fiber. Untreated rayon can shrink by 10% when washing in the washing machine.
2. High wet strength (polynosic) rayon (high wet modulus rayon)):
In order to improve the above-mentioned negative properties of rayon fiber, various researches have been made and rayon fiber has been modified by different processes. These are called high strength viscose rayons and because of their high durability, especially when wet. high wet modulus abbreviated form of HWM are symbolized by HWM rayon In addition to its high wet strength, it has other properties of viscose. It can be washed in washing machines, dried in dryers and can perform as well as cotton products during these processes. In order to increase its brightness, it can be subjected to mercerization process like cotton. In the clothing industry, it is called polynosic rayon or modal with its trade name. It differs from viscose in the degree of polymerization, degree of crystallization, size of the crystalline regions, degree of orientation and uniformity in the filament. For this reason, the durability, breaking strength, flexibility and friction resistance of the fabrics produced from these fibers are higher than the normal rayon fiber. Its strength is 3,0 – 4.0 g/denier when dry and 1.9 – 2.5 g/denier when wet. It does not swell as much as viscose fiber with water.
3. High tenacity rayon:
It is a modified form of viscose, twice the strength of HWM rayon. It is used in cord fabrics and in the industrial field.
4. Cupramonium rayon:
Although it is similar to other rayons in terms of properties, it has not been produced recently because environmentally harmful substances are used during its production.