Textile Glossary

Fully Oriented Yarn (FOY)

Definition

FOY (Fully Oriented Yarn) is a synthetic filament yarn that is both spun and fully drawn in a single production step during the spinning process, resulting in maximum molecular orientation and crystallization of the polymer chains. Unlike POY (Partially Oriented Yarn), no subsequent drawing step is required. The result is a dimensionally stable yarn with defined mechanical properties such as high tenacity and low residual elongation.

Use in the textile industry

FOY is used primarily in applications requiring dimensionally stable, shape-retaining woven or knitted fabrics, such as technical textiles, lining fabrics, and smooth apparel fabrics. Due to its low shrinkage and uniform dyeability, it is especially suitable for articles that must not show significant take-up during further processing. Compared to textured yarns, FOY produces a smooth, lustrous surface.

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Frequently asked question

POY (Partially Oriented Yarn) is only partially drawn during melt spinning and therefore has incomplete molecular orientation; it frequently serves as an intermediate product for texturing or further drawing. FOY, by contrast, is already fully drawn during the spinning process and can be processed directly into woven or knitted fabrics without an intermediate step. As a result, FOY exhibits higher tenacity and lower residual elongation compared to POY.

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