Staple vs. Continuous Filament

Staple and Continuous Filament Fiber

Spun (staple) fiber

Synthetic spun fibers are first extruded, which occurs when synthetic fibers like Nylon begin as pellets and are then melted into hair-like filaments.  These filaments are then heated, cooled, and crimped to improve strength and impart other physical characteristics. Next, the fibers are cut into lengths of 7-8 inches, packed into bales, and sent to a spinning facility for processing into yarn.

At this points, the strands of fiber require three critical steps in preparation for
spinning:

• Blending - Blending carefully mixes the fiber strands to prevent yarn streaking during the dyeing process.
• Carding - Carding strengthens the fibers.
• Drafting - This step continues to blend the fibers, aligning them in parallel form to facilitate spinning.

After spinning, the yarn is plied and twisted to develop certain characteristics, such as the degree of luster, bulk, and texture. It is then heat-set to establish the twist, giving the yarn “memory” to maintain its appearance.

Advantages

Carpet made from spun yarn can produce a variety of looks, including dense, luxurious finishes, a capability that was at one time unique to this type of yarn. Spun nylon yarn can also feature a soft, wool-like luster, and it is versatile enough to be constructed in a wide variety of weights and textures.

Spun colors, too, may be subtle and natural looking, as these fibers accept dyes much in same way as wool.

Disadvantages

On the other hand, several factors have lessened the appeal of carpets of spun yarn. Changing consumer tastes have moved away from dense, tailored saxony looks for which spun yarn was so ideally suited. In addition, the numerous steps in manufacturing spun yarn make the process costly, and decreased demand only exacerbates the problem.

Perhaps the most common complaint related to carpets of spun yarn is pilling and
fuzzing. Since the yarn is made up of many shorter fibers twisted together, the staple fibers will shed loose filaments and necessitate frequent vacuuming, at least for a period of time. This is not a manufacturing problem that affects long-term performance, but it may require a little extra housekeeping time.

Continuous filament (BCF) fiber

BCF fiber - bulked continuous filament 

Bulked continuous filament is different.  Instead of creating many 7-inch or 8-inch lengths of strands, continuous filament is extruded as one long string. These strings are then twisted and heatset together to form strands of yarn. The yarn may also be texturized to curl, or kink; this also increases the bulk and gives the yarn twist more memory for better texture retention and wear resistance.


Advantages

Because BCF fiber is one continuous strand of fiber, it will not shed loose fibers like
staple fibers. It is also more cost-effective to manufacture continuous filament yarn
today, because of the fewer steps required.

Perhaps most important are advances in fiber technology, resulting in the ability to
create filament looks that were not practical in the past. Technology has also made
filament production faster and even more economical than before. Styles that were the almost exclusive domain of spun yarn can now be made with continuous filament yarn.


Conclusion
The percentage of products using continuous filament yarn and spun yarn have
essentially been reversed over the past few years, with the vast majority of Shaw's carpets now being made using continuous filament.  

Carpets of spun yarn will continue to be an option for a variety of styles and looks, but they no longer enjoy the widespread use they once maintained.