Pure rayon does shrink in the dryer.

More Info: Viscose rayon, that is rayon that is not woven with another material, has a low wet strength, which makes it vulnerable to shrinking in the wash.  Viscose rayon garments are usually labeled as dry clean only.  Many rayons are mixed with other fabrics such as polyester and if present in a ratio of at least 30% of the overall garment, it is generally safe to wash and dry.  Polynosic rayon is a rayon that has been modified to have a high wet strength and is also safe to wash and dry.

Selecting a Blouse Ohio State University College of Food, Agricultural, and Environmental Sciences

What Is Rayon?

Rayon is a manufactured semi-synthetic fiber derived from processed cellulose. The highly adaptable rayon fibers can be manipulated during the manufacturing process to mimic a number of completely natural fibers such as silk or cotton. The resulting fabric is lightweight and easy to dye, which makes rayon a popular fabric in warmer climates. Unfortunately, rayon deteriorates relatively quickly with age. The fabric begins to lose elasticity, so the fiber may lose both color and shape. However, rayon is still a less expensive alternative to some natural fibers.

How Do You Care for Rayon?

Rayon garments can require special care and handling in order to continue looking their best. If the label specifies dry-cleaning only, washing at home is not advised. Otherwise, washable rayon garments can be laundered on the gentle cycle using cool water. Take the garment out of the washer immediately for fewer wrinkles and increased fabric life. Roll garment in a towel if needed to remove excess water, then hang on a padded hanger to dry.