"Modal is a bio-based fiber made by spinning reconstituted cellulose from beech trees. It is about 50% more hygroscopic, or water-absorbent, per unit volume than cotton is. It is designed to dye just like cotton, and is color-fast when washed in warm water (I usually avoid color fast fabrics). Modal is essentially a variety of rayon.
Textiles made from Modal do not fibrillate, or pill, like cotton does, and are resistant to shrinkage and fading. They are smooth and soft, more so than even mercerized cotton, to the point where mineral deposits from hard water, such as lime, do not stick to the fabric surface. Like pure cotton, modal needs to be ironed after washing.
Modal is a registered trademark of Lenzing AG, an Austrian company specializing in textiles and fibers, particularly natural fibers made from cellulose. In the United States, pure Modal has begun being used in household linens such as towels, bathrobes, and bedsheets. Bed Bath & Beyond, for example, sells its newly-released Modal sheets under the name Pure Beech. Indian textile companies, in particular, have taken to Modal, and are expected to produce around 4000 tons of it in 2005"
I would start with the Lenzing AG website, if there is one.