The composite yarn (thread) is uniform on the outside and is composed of yarns of different components. There are two types of this:
1. Core spun yarn, its central yarn is covered by fibers or another yarn. For example, the elastic thread has a rubber band in the center, and its periphery is wrapped in yarn. Another example is polyester-cotton yarn, which is wrapped in polyester filament with high quality, the cotton shell makes the yarn sewable, and the polyester core makes the yarn strong.
2. Wrapping yarn, wrapping with filament around the periphery of the untwisted fiber bundle (staple fiber or filament).