What is Modal and why is it so absurdly soft?

I should start by recommending that if you are not familiar with modal, you should immediately buy a shirt made out of it. It is like really soft light cotton, just drapes wonderfully and is like magic. And it is not expensive.

Evidently it is made from reconstituted cellulose from beech trees. This evidently means it is a variation on rayon.

So what exactly is rayon? Absolutely fascinating. So rayon is "technically" not an artificial fiber because it is made from trees BUT is treated as artificial because of the enormous amount of work required to turn the beech tree into rayon. Which doesn't really make sense to me because it's not as though they just picked the cotton for my sweatshirt and boom, there it was, but whatever. Miscellaneous information: rayon was originally created in the late 1800s by the French as a silk alternative.

The process of production is rather complex, so I'm just going to quote it from here: "The manufacture of rayon begins with cellulose, frequently extracted from wood pulp, although any plant material with long molecular chains is suitable. The cellulose is steeped in caustic soda, which concentrates some of the cellulose into soda cellulose, which is then rolled or pressed to remove excess soda solution. After pressing, the cellulose is shredded into a substance called white crumb.

The white crumb is allowed to oxidize, forming shorter molecular chains, and treated with carbon disulfide. The soda cellulose reacts with this substance, forming yellow crumb due to inorganic compounds that emerge during the chemical process. This yellow crumb is dissolved in a caustic solution, which relaxes the hydrogen bonds in the cellulose, producing a highly viscous substance. This substance gives its name to the manufacturing process, called the viscose process.

This viscous fluid is allowed to age, breaking down the cellulose structures further to produce an even slurry, and then filtered to remove impurities. Small air pockets are forced out to ensure a strong, even fiber, and the mixture is forced through a spinner, which forms many even strands of fine thread that enter a setting solution to form cellulose filaments: also called rayon. The rayon is stretched to form a strong, even bond, washed, and then formed into rayon fabric."

The process for making modal is a variation on this, known as polynosic. So some of the differences that make rayon very different from the magnificence of modal include that the molecular chain length of the cellulose is twice as long as traditional rayon and it is actually a mix of rayon and polyester fibers.

Modal is trademarked by Lenzing AG, which also has Tencel, another excellent fiber. Here is a video babbling on about the lovely textiles -it is in German, but it is pretty easy to get the idea.