Filament
Also searched as: continuous filament, monofilament, multifilament
A fiber of continuous or very long length, unlike a staple fiber.
In detail
A filament is a very long fiber that can be used continuously rather than assembled from many short lengths. A monofilament yarn uses one filament; a multifilament yarn brings several together. Manufactured filaments may also be cut into finite lengths for staple-fiber processing.
The science and numbers
Silk is the natural reference point. A Bombyx mori cocoon is wound from one continuous filament; the FAO reports total lengths of about 600 to 1,500 m, of which about 80 percent is typically reelable, and individual cocoon filaments average only about 1.5 to 3.5 denier, so raw silk combines filaments from roughly 2 to 20 cocoons. Manufactured filaments are extruded through spinneret holes and drawn, which aligns chains and raises tenacity; partially oriented yarn can then be draw-textured, a route one review says handles about 60 percent of melt-spun filament yarn. Because filaments run the full length of the yarn, multifilament yarns need little or no twist to hold together, whereas staple yarns rely on twist-generated friction. Filament tow can also be cut into staple, so a polymer name alone never tells you which form a yarn uses.
A practical example
Think of a continuous strand compared with a rope assembled from overlapping short pieces. Both can become useful yarns, but their construction differs. A yarn specification should identify whether a denier value refers to the complete multifilament yarn or to each filament.
What to distinguish
Filament does not mean synthetic, and staple does not mean natural. Reeled silk provides a natural filament example. The words describe length and construction, while the fiber name describes material identity.
Origins and history
The word is built on the Latin filum, thread. For most of history silk was the only natural textile filament used at scale. The first manufactured filaments came from cellulose solutions: in 1890 Louis-Henri Despeissis patented spinning fibers from cuprammonium cellulose solutions, and by 1891 Max Fremery and Johann Urban were making lamp filaments by this route at Oberbruch near Aachen. Melt spinning followed in the twentieth century with nylon at DuPont, where Wallace Carothers' group developed polyamides that could be drawn into strong filaments.
Related terms
Sources & further reading
- BISFA: Terminology of man-made fibres (2017)
- CottonWorks: Staple yarn
- FAO: Silk reeling and testing manual, Chapter 6
- US EPA AP-42 Section 6.9: Synthetic fibers
- Preprints.org: A review on false-twist texturing
- Britannica: Cuprammonium rayon
Technical references reviewed 2026-09-22. Examples are illustrative. Industry organizations and manufacturers describe their own fields; their references are not independent product endorsements. Figures are approximate and depend on the stated test conditions.