Bulked continuous filament yarn

BCF yarns n. Bulked continuous filament yarns for carpet trade, usually nylon, polypropylene, or polyester. 

The production machines can be normal spin-draw winders, as for the other melt-spun fibers. But here also, compact machines have been developed, for example for bulked continuous filament yarn (BCF, for carpet) with all the process steps on one machine, at an end speed of <1000 m min h Polypropylene is small in textile applications (in sportswear) but it has a reasonable position in high-tenacity yarns, in low-temperature applications such as ropes, cables, and geotextiles. It should be added that polypropylene can be drawn to high ratios (see Section 17.7.2). This results in very good tenacities, but the helix configuration of the isotactic chain in the crystals severely limits the modulus. 

PTT polymer pellets must be dried to a moisture level of <30 ppm, preferably in a close-loop hot air dryer, to avoid hydrolytic degradation during melt processing. Drying is canied out widi 130°C hot air witli a dew point of <—40°C for at least 4h. Because of tire faster ciystallization rate, PTT pellets are already semicrystalline after pelletizing, and do not require pre-crystallization prior to drying as with PET. The dried polymer is extruded at 250-270 °C into bulk continuous filaments (BCFs), partially oriented yarn (POY), spin-draw yarn (SDY) and staple fiber. 

Bulked continuous filament (BCF) carpet yarns are heavy decitex bundles of fiber that are bulked by passage through a turbulent blast of steam or hot air well above Tg. The turbulence blows the yarn about and entangles the filaments, and then heat sets them into place, giving them a permanent crimp. Polymers like PET do not have very good resilience as carpet fibers, but PTT (Eg = 45°C) lends itself very well to the BCF process and has excellent resilience [38]. 

Producer-textured yarns n. Continuous filament yarns that have been bulked during manufacturing by the fiber producer. 

Bulked continuous filament (BCF) processes are similar to CF processes, but one main difference is that in BCF a texturizer is an integral part of the process, to impart bulk to the fibers, through crimps or kinks. Commonly, BCF fibers are of ca. 20 dpf, with yarns being in the vicinity of 2000 denier. Polypropylene homopolymer with MFRs in the range of 12-20 MFR and normal MWD is typically used. BCF yarns are mainly used as carpet face yarns and in fabrics for upholstery. 

Keywords use, application, chemical fiber, polypropylene fiber, monofilament, multifilament, staple fiber, tapes, spunbond, melt blown, split film, textile yarn, knitted fabrics, clothing, nonwoven fabric, home textiles, upholstery, geotextiles, agrotextiles, composites, medical textiles, automotive textiles, bulk continuous filaments (BCF), Eco-textiles, integrated fabric. 

Even when crimp is fully developed it is easy to pull out (low energy) and difficult to translate into noticeably bulkier woven and knitted fabrics. It does however improve the absorbency and the cohesion of the staple (important in spun-yarn and nonwoven making) and gives a subtly different texture to woven fabrics. Coarse crimped rayon was the leading synthetic carpet fiber in Europe in the 1960s, but has since been replaced by the highly durable bulked continuous filament nylon yams. Crimp is most important in rayon used for hygienic absorbent products. 

The dried polymer is extruded at 250-265° C into fibers using conventional processing machines for bulk continuous filaments (BCF), partially oriented yarn (POY), spin-draw yarn (SDY), and staple fiber. 

Most bulked continuous filament fibers are produced for apparel applications and are processed using a two-step method. In the first step the fibers are spun as straight flat yarns at speeds between 3500 and 5500 m per min, which results in a fiber that is only partially oriented but fully crystallized. 

Cabled yarns a defined number of plied yarns are brought together with a slight twist. Texturized and voluminized products an air stream leads to the formation of loops in overfed continuous filament and imparts bulk. 

Extrusion takes place through several spinnerets at the same time. The filaments are quenched with air, and the group from each spinneret is then taken up to produce yarn, the draw ratio and degree of orientation depending on the take-up equipment, on whether the process is single or two stage, and on the end use. Continuous filament fibers are not crimped or texturized as produced. Such bulk-... 

Often continuous filament fibers require some type of bulk or twist before they can be used in textile applications. This is accomplished in carpet yarns generally produced from nylon 6, nylon 66 or polypropylene by using a BCF machine (Oerlikon Textile GMBH and CO., 2011). These lines are similar to the one-step fiber lines described above, except that the spinning speed... 

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