Core spun yarn consists of a core thread, spun round by twisted staple fibers, known as the "wrapper". One or more endless filaments form the core thread. Often the core thread is made of polyester, the spun wrapping of cotton. Such a core spun yarn can be recognized by the short description PES/CO.

Core spun yarns are mainly used on very fast sewing machines such as sewing automats. Since the yarn in the needle's eye rubs against the sewing needle, the sewing needle heats up at high speeds. As long as the sewing machine is running, the yarn touches the hot sewing needle only very briefly and the heat does not harm the yarn. But as soon as the sewing machine stops, the sewing thread lies for a certain time on the hot needle. Then synthetic fiber yarn, e.g. made of polyester, melt. When the thread melts, it tears immediately or forms melting beads. Melting beads prevent the thread from sliding through the eye of the needle, causing the thread to tear.

The cotton spinning works as padding between the hot sewing needle and the polyester core thread. Thanks to this padding, the needle transfers less heat to the core thread. This reduces the risk of the polyester thread melting and tearing the yarn during the sewing process.

To avoid the disadvantages of cotton (rotting, not resistant against many chemicals, high moisture absorption, shrinkage), the spinning mill can also wrap the core thread with synthetic fibers, e.g. made of polyester. Such core spun yarn is often recognized by the short description PES/PES. Because the padding synthetic fibers also melt at high temperatures, the heat resistance and thus the possible sewing speed are significantly lower than for PES/CO, core spun yarn wrapped with cotton. Due to their core thread of continuous filaments, core spun yarns are more tear-resistant and abrasion-resistant than simple staple/spun yarns of the same gauge.

Saxotex keeps various core spun yarns made of polyester/cotton and polyester/polyester from 5,000 m per bobbin in stock for immediate delivery. We usually procure grades and colors not in stock within one week. For not stocked yarns, the minimum purchase quantity is 10 bobbins.