Generally, fibers below 30D can be called ultrafine fibers.

There are two types of fibers on the market with microfiber varieties, polyester and nylon,

What I have seen, the finest polyester has 20D, and the finest nylon has 10D

That is to say, microfiber has a part of polyester, but microfiber is not only polyester.

By the way, the varieties of chemical fiber products are diversified. The worst ones are of course electrostatic fading, but there are also varieties that are breathable, moisture-permeable, anti-static, and waterproof and fireproof. As for the color fastness, I don’t know how much stronger than cotton.

Generally speaking, the fabrics made of this specification are microfiber fabrics