As the oldest manmade fiber, Rayon has been in existence for over 100 years. Originally devised as a cheaper alternative to silk, Rayon is a versatile fabric made from natural substances such as wood pulp and plant cellulose. The result is a semi-synthetic, versatile fabric that carries many of the same characteristics of all natural fibers (such as silk, wool, cotton and linen).
Over the course of time, improvements to the processing of Rayon have produced a few variations of the original fiber. These derivatives include: High Wet Modulus (HWM Rayon), High Tenacity Rayon and Cupramonium Rayon. While these materials have applications in the biomedical and other industrial fields, the majority of Rayon is produced for apparel and household furnishing.
Most garments are manufactured by using either “regular rayon” or HWM rayon. “Regular rayon,” or rayon that is made without any additives is known as viscose. HWM rayon’s differentiation lies in the way it is produced; it is subjected to a modified process, in which it’s exposure to caustic chemicals is reduced and the fiber is stretched to a greater degree than viscose rayon.
Viscose is a favorable fabric due to its soft feel, capacity to absorb moisture (up to 50% more than cotton), and ability to be easily dyed. Viscose, especially those fabrics with fine fibers, drapes wonderfully. Rayon can also withstand a higher heat threshold than other synthetic or semi-synthetic fibers. Yet, like wool or silk, viscose rayon has very little stability when wet, and can lose up to 70% of its original strength. Consequently, when viscose rayon is saturated, it has the propensity to shrink (by as much as 10%), as well as distort the original shape of the garment. This characteristic also makes it a poor fabric to hold pleats or a wrinkled appearance. Additionally, viscose rayon is a poor insulator and is not conducive for trapping body heat.
HWM Rayon is also known as Model or Lyocell. These fibers are manufactured with the same materials as viscose rayon, but are processed in a way that adds resiliency. The result is a fabric that has the same “natural” feel, but with the ability to withstand water and saturation. Most HWM rayon’s are blended with natural fibers to give a silkier appearance and hand, or to improve strength.
HWM rayon’s may be machine washable (check the care label to be sure), but with a few precautions: Always use cold or lukewarm water. Never wring or twist the garment. Either hang on a non-rust hanger or lay flat to dry. If you are pressing the garment at home, turn the clothing inside out and iron on low to moderate heat setting.
For the best care, it is recommended that all rayon fabrics be dry cleaned, due to the fabric’s low tensile strength when wet and dry cleaning’s ability to preserve color.