Continuous filament polyester can be supplied in many forms but the most common for industrial applications are partially orientated yarn (POY) and fully orientated yarn (FOY).

What is Partially Oriented Yarn (POY)?

Partially oriented yarn is produced from the melting and extrusion (melt spinning) of the polyester chip or flake.  During the spinning process the filaments are stretched or drawn as much as five times their original size to orient the polymer to meet the desired evenness, strength, shrinkage, and elongation properties.  So the term partially oriented yarn refers to multi-filament that is only partially stretched. POY is generally lower tenacity and less uniform than fully oriented yarn (FOY).  POY is mainly used in texturizing to make textured yarn and can also be used in draw warping for weaving and warp knitting of fabrics.

What is Fully Oriented Yarn (FOY)?

FOY Polyester (also called Fully Drawn Yarn - FDY), is produced by a process similar to POY manufacturing except that the yarn is produced at even higher spinning speeds coupled with intermediate drawing integrated in the process itself. This allows stabilization through orientation and crystallization. FOY is mainly used as weft or warp in making fabrics. FDY can be knitted or woven with any other filament yarn to get fabric of various different varieties. FOY Polyester yarn is used for industrial applications requiring uniformity and consistent tenacity, elongation, and shrinkage.  Most binder yarns, industrial sewing threads, and hose reinforcements are produced from FOY polyester.

There are many different types of industrial polyester yarn, with varied physical properties that are controlled through the polymer formula and processing conditions of the POY or FOY yarn.  Selecting the right yarn type can be challenging, so working with a reliable partner to match the right polyester yarn to your application is the key to quick optimization and product development.