Modal is a type of rayon, a semi-synthetic cellulose fiber made by spinning reconstituted cellulose, in this case often from beech trees. Modal is used alone or with other fibers (often cotton or spandex) in household items such as pajamas, towels, bathrobes, underwear and bedsheets.
Manufacturers claim a number of advantages for the fiber: about 50% more hygroscopic (water-absorbent) per unit volume than cotton, takes dye like cotton, color-fast when washed in warm water, resistant to shrinkage and fading but prone to stretching and pilling. It is also claimed that mineral deposits from hard water do not stick to the fabric surface. It is smooth and soft, more so than mercerized cotton, though some perceive it to have a synthetic texture. Modal fabrics should be washed at lower temperatures and, like cotton, are often ironed after washing.