Multi-component fiber

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A multicomponent fiber (synonym: multicomponent fiber ) consists of at least two firmly, but separable, interconnected polymers with different chemical and / or physical structures.

Multi-component fibers are predominantly made from two polymer components. They are therefore called bicomponent fibers .

The aim of the development of bicomponent fibers (also called twin fibers) was to avoid the difficult and costly development of new chemical combinations, but nevertheless to achieve fibers with new desired properties.

Structure of bicomponent fibers

There are a large number of geometrical arrangements of the polymers, whereby the four types shown in the adjacent picture have priority in the fiber cross-section:

a) side-by-side; b) sheath / core; c) matrix / fibrils; d) Pie pieces
a) side-by-side; engl. Side-by-side (S / S types).
Two different polymers are brought together before the spinning process and spun through a nozzle bore so that they lie side by side along the length of the filament (usually in proportions of 50/50). If the shrinkage behavior of the polymers varies, a fiber crimp can be obtained by heat treatment.
b) sheath / core (M / K types); engl. Cover / Core (C / C) or Sheath / Core (S / C) or also Kern / Mantel (K / M types; English Core / Sheath (C / S) (both with concentric and eccentric core).
The different polymer components are brought together in a ring spinneret in such a way that one component forms the core, the other the enveloping jacket. For example For example, if the core has a higher melting range than the cladding, these fibers can be used for thermal bonding of the fleece.
c) matrix / fibrils (M / F types); engl. Islands-in-the-Sea).
The fibers consist of two incompatible polymers of different types. The inner melt (fibril melt) is extruded through a larger number of tubes into the pre-drilled hole of the nozzle plate for the outer melt (matrix) and then the components combined in the spinning mass are spun out together. The fine fibrils (microfibers) with diameters generally less than 10 µm are protected by the matrix, which is common textile processing up to z. B. enables the formation of a fleece. By dissolving the matrix, the remaining microfibers in the created product can be exposed (see Alcantara ).
d) Pie pieces (also orange pieces) structure.
The segments of a circle (pieces of cake) are formed by an intermediate star made of a different polymer. During production, use is made of the fact that some polymers in the melt flow during the spinning of the elementary fibers z. B. easily stick together from an orange-type spinneret, but these traps split again when they cool down and under mechanical loads. This creates microfiber bundles with a wedge-shaped cross-section. Useful combinations are PET-PP and PET-PA. The microfibers that are created are often used for nonwovens.

Historical development

As a forerunner of bicomponent fibers, the "angel hair", which was produced in the 19th century and which had crimped glass fibers due to the joint processing of two glasses of different chemical composition, can be used. Early precursors also include acetate fibers that have been saponified back to cellulose on the surface (partially substantivated acetate fibers), which is an early form of the sheath-core fibers, as well as an early form of animalized cellulose, which was produced by spinning protein bodies in cellulose and as early matrix fibrils -Type can be viewed.

However, the actual development did not begin until the 1930s at IG Farben with side-by-side bicomponent fibers made from two differently matured viscoses or from cellulose acetate and polyvinyl chloride . The aim was to achieve a wool-like crimp in the fibers. During the Second World War, the American Viscose Corporation largely only developed bicomponent fibers with viscose of different compositions.

In 1958 DuPont introduced the first polyacrylonitrile bicomponent fiber, which produced filaments with a mushroom-shaped cross-section by dry-spinning two polymers through a spinneret . As a result, a helix-like crimp was ultimately achieved, as with wool.

Bicomponent fibers by melt spinning were first developed by the Swiss company Viscosuisse and DuPont from the 1960s onwards and brought onto the market as polyamide yarns by DuPont from the mid-1960s under the brand name Cantrece.

After the development of bicomponent fibers initially aimed primarily at crimped man-made fibers for decades, with the growing nonwovens industry from the 1990s, the focus was primarily on binding fibers of the core-sheath type. The production of superfine fibers ( microfibers ) through the splitting of multilayer bicomponent fibers also became important from the early 1970s.

Individual evidence

  1. ↑ Ursula Völker, Katrin Brückner: From fiber to fabric - Textile materials and goods . 35th, updated edition. Publishing house Dr. Felix Büchner. Hamburg 2014, ISBN 978-3-582-05112-7 , p. 76.
  2. ↑ Günter Schnegelsberg: Manual of the fiber - theory and systematics of the fiber. Deutscher Fachverlag, Frankfurt am Main, 1999, ISBN 3-87150-624-9 , p. 563.
  3. ↑ Franz Fourné: Synthetic fibers: production, machinery, Features: Manual for system planning, machine design and operation. Carl Hanser Verlag, Munich Vienna 1995, ISBN 3-446-16058-2 , p. 539.
  4. ↑ Hans-J. Koslowski: Chemical fiber - Lexicon. 12th, expanded edition, Deutscher Fachverlag, Frankfurt am Main 2009, ISBN 978-3-87150-876-9 , p. 38.
  5. ↑ Hermann Klare: History of chemical fiber research. Akademie-Verlag, Berlin 1985. p. 355.
  6. ↑ Menachem Lewin (Ed.): Handbook of Fiber Chemistry . Third edition. Taylor & Francis Group, Boca Raton 2007. ISBN 978-0-8247-2565-5 , pp. 23/24.
  7. ↑ Ursula Völker, Katrin Brückner: From fiber to fabric - Textile materials and goods. 35th, updated edition. Publishing house Dr. Felix Büchner. Hamburg 2014, ISBN 978-3-582-05112-7 , pp. 76/77.
  8. ↑ Walter Loy: Chemical fibers for technical textile products. 2nd, fundamental revised and expanded edition. Deutscher Fachverlag, Frankfurt am Main 2008, ISBN 978-3-86641-197-5 , page 23/24.
  9. ↑ Stefan Mecheels, Herbert Vogler, Josef Kurz: Culture and industrial history of textiles . Wachter GmbH, Bönnigheim 2009, ISBN 978-3-9812485-3-1 , p. 449.
  10. ↑ James C. Massow (Ed.): Acrylic Fiber Technology and Application . CRC Press, Boca Raton 1995. ISBN 978-0-8247-8977-0 , pp. 171/172.
  11. ↑ Menachem Lewin (Ed.): Handbook of Fiber Chemistry . Third edition. Taylor & Francis Group, Boca Raton 2007. ISBN 978-0-8247-2565-5 , p. 814.
  12. ↑ Stefan Mecheels, Herbert Vogler, Josef Kurz: Culture and industrial history of textiles . Wachter GmbH, Bönnigheim 2009, ISBN 978-3-9812485-3-1 , p. 450.