Development of filament and staple fibers

Purpose

Solution spinning of fibers results in tows, in other words bundles of multiple fibers packed in the longitudinal direction. The number of fibers in the tow is determined by the number of capillaries in the spinnerets used for extrusion. The tow is processes throughout coagulation, washing, stretching, spin finish application, drying, where fibers stay packed together, as extruding single fibers is not economically feasible. Depending on the intended application, the tow can be processed as filament or staple fibers, suitable for yarn and thread manufacturing.

Method

We perform research trials aimed at the development of both filament and staple fibers.

Filament fibers

Filaments are continuous and unbroken fibers that can be used in their original form as they emerge from solution spinning or can be twisted to form yarns and threads. The number of fibers in filament yarn is determined by the number of spinneret capillaries employed during the dope extrusion. 

Staple fibers

Filaments can be transformed into staple fibers using a cutting operation. Typically, crimping is also performed to aid in the yarn spinning process by creating interlocking points for the fibers to grip onto each other. Moreover, spin finish plays a crucial role in yarn spinning of staple fibers and thus requires careful optimization. When aiming for staple fibers, the number of spinneret capillaries used for extrusion is not restricted by the yarn thickness, allowing for solution spinning of very thick tow. The tow can be cut into staples and used for yarn spinning, with yarn thickness subsequently controlled through such operations as carding, drawing, roving, and ring or open-end spinning.

Characterization of fibers

We perform the following testing of fibers:

• Mechanical testing (e.g. dry and wet tenacity).
• Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS).
• Degree of polymer orientation (birefringence).
• Specific surface area (BET).
• Crystallinity (CP/MAS NMR and SAXS/WAXS).

Delivery

We have knowledge and equipment to develop and optimize solution spinning processes to produce filament and staple fibers, yarns and threads. Deliverables may include optimized process parameters summarized in a report or actually produced fibers. Please contact us for more information.

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