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Composite Fiber

Composite fiber is a multicomponent fiber that combines at least two polymers of different properties and/or chemical compositions. Alfa Chemistry provides composite fibers to meet diverse fiber material needs.


With the right combination of polymers, manufacturing conditions and added additives, multicomponent fibers with desired properties can be obtained. The advantages of composite fibers include increased dyeability, decreased flammability, increased water absorption, increased photothermal stability, increased strength and elastic recovery.

According to the number of phase components, it can be divided into bicomponent and multicomponent composite fibers. Most of the currently developed conjugate fibers are bicomponent fibers. According to the shape of the cross-section, bicomponent fibers include side-by-side, sheath-core, and island-in-the-sea types, etc. The figure below lists some common types of fiber cross-sections. [1]


  • Side-by-side type: Side-by-side composite fibers are fibers composed of polymers with different properties or structures arranged side by side and composited along the fiber axis. The ratio of each component can be symmetrical or asymmetrical. The most important feature of this fiber is that it can take advantage of the difference in shrinkage properties of each component to create an ideal wool-like three-dimensional crimp. Therefore, side-by-side composite fibers are mainly used to produce large-volume self-crimping fibers.
  • Sheath-core type: This is a fiber in which two polymers are continuously formed along the longitudinal direction of the fiber to form a skin layer and a core layer, respectively. Using the sheath-core structure, special-purpose fibers can be manufactured. For example, the flame-retardant polymer is used as the core and the ordinary polyester is used as the skin to make flame-retardant fibers.
  • Island-in-the-sea type: This is a composite fiber in which the dispersed phase polymer is uniformly embedded in the continuous phase polymer. The island component of sea-island fiber is generally polyester (PET) or polyamide (PA), and the sea component compounded with it can be polyethylene (PE), polyamide (PA6 or PA66), polypropylene (PP), polyethylene Vinyl alcohol (PVA), polystyrene (PS), etc.

Typical Product

Polyethylene and polypropylene composite fibers

One of the most commonly used multicomponent fibers includes polyethylene (PE) and polypropylene (PP), which are polymers with different melting points. The resulting material is lightweight, strong, soft and comfortable, dries quickly, and has high abrasion and stain resistance.

Research and Application

As a kind of fiber variety with special style and performance, composite fiber has been widely used in people's life, industry, medical treatment, optoelectronic communication and other fields, and has become an indispensable fiber material.

In advanced research, composite fibers can be used as luminous fibers. In 2004, Shim investigated the luminescence and mechanical properties of photoluminescent core bicomponent fibers produced in a sheath-core morphology. In 2018, Haolong Xue et al. developed a novel skin-core structure luminous fiber that emits red light in the dark. [2]

Structure of xanthene derivative (a) and luminous fiber (b).Structure of xanthene derivative (a) and luminous fiber (b).


  1. Irwin M. Hutten. Handbook of Nonwoven Filter Media 2007, 103-194.
  2. Haolong Xue, et al. Journal of Materials Science: Materials, in Electronics, 2018, 29, 18045–18050.

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