Polyester fiber spinning

Mechanical Properties. Polyester fibers are formed by melt spinning generally followed by hot drawing and heat setting to the final fiber form. The molecular orientation and crystalline fine stmcture developed depend on key process parameters in all fiber formation steps and are critical to the end use appHcation of the fibers. 

Fig. 2. Ultrafine fibers are produced by spinning bicomponent or biconstituent polymer mixtures, highly stretching such products to ultrafine deniers, and extracting or otherwise removing the undesked matrix carrier to release the desked ultrafine fibers (30). For example, spinning polyester islands in a matrix of polystyrene and then, after stretching, dissolving the polystyrene to leave the polyester fibers cospinning polyester with polyamides, then stretching,...

Steam-heated aluminum castings are used for the melt spinning of nylon and polyester fibers and have been used for storage of raw materials during manufacturing, as well as for storage of acetic acid in cellulose acetate plants. 

Fiber spinning, 11 174, 175, 170-171 carbon-nanotube, 13 385-386 methods of, 16 8 models of, 11 171-172 of polyester fibers, 20 12-15 Fiber structure, of aromatic polyamides, 19 727... 

This article is an overview of the novel technology of self-reinforced LCPs with polyesters, poly(ethylene terephthalate) (PET) and poly(ethylene naphtha-late) (PEN) [10-13, 21, 23], LCP/polyester blends in a polyester matrix form in situ fibrils which improve the mechanical properties. LCPs have an inherently low melt viscosity, and provide LCP/polyester blends that effectively lower the melt viscosity during melt spinning [24], and fast injection-molding cycles. The miscibility between the LCP and polyesters can be controlled by the degree of transesterification [25] in the reactive extrusion step, and fibril formation in LCP-reinforced polyester fibers has been studied. 

Aromatic polyesters had been successfully synthesized from the reaction of ethylene glycol and various aromatic diacids but commercialization awaited a ready inexpensive source of aromatic diacides. An inexpensive process was discovered for the separation of the various xylene isomers by crystallization. The availability of inexpensive xylene isomers allowed the formation of terephthalic acid through the air oxidation of the p-xylene isomer. DuPont produced polyester fibers from melt spinning in 1953, but it was not until the 1970s that these fibers became commercially available. 

Microfibers are also made by simple extrusion through a spinneret with a smaller hole than normally employed for fiber production. The third method involves spinning a bi-component fiber and using a solution to split the fiber into smaller pieces. Initially, bi-component fibers in the range of 2-4 denier are spun and then split into microfibers. If a 32-segment pie of nylon-polyester fiber is used, the final fineness is on the order of 0.1 denier. Brushing and other techniques can be used to enhance the effects. Hollow fibers are also being used... 

In contrast to disperse dyes solvent dyes for spin dyeing of polyester fibers are initially soluble in the polymer, thus avoiding the dipersing processes for the application of disperse dyes or pigments. 

Various furan compounds have been incorporated into a polyester fiber to provide electrostatic resistance toward antistatic fabrics <1999KRP160475>. Up to 1 wt.% of the furan compound was combined together with a polyoxy-alkylene glycol compound and a nonreactive lithium alkylsulfonate to copolymerize the polyester. Upon drying, melt spinning, and stretching, the formed polyester fibers showed excellent electrostatic resistance. 

Like nylon, polyester fibers are made from linear-condensation polymers by melt spinning, followed by drawing. Similar to nylon, the drawing treatment involves a stretch ratio of 5. The drawing of polyester fiber is done above its glass transition temperature of 80°C. 

A very cohesive lubricant to be used in the spinning of low crimp, low denier nylon or polyester fibers. 

A versatile fiber lubricant recommended for processing nylon and polyester fibers. It has an excellent balance of fiber-to-fiber and fiber-to-metal lubrication and good antistatic properties. PROGALUBE 339 also prevents buildup of monomer on pin-drafters and spinning frames. 

We already have reported on the replacement of the terephthalic acid with kinked diphenylether dicarboxylic acids (4). 3,4 - and 4,4 -Dicarboxydiphenylether (3,4 -0 and 4,4 -0) were synthesized and all-aromatic polyesters were prepared represented by structure 1. These polyesters were thermotropic with melt transitions decreasing to about 200°C with increasing replacement of the terephthalic acid with the kinked monomers. The polymers generally were thermally stable without measurable weight loss until well over 400°C. We wish here to supplement our previous studies with rheological measurements and fiber spinning of the polymers, including some measurements of fiber properties. 

Figure 5. E -modulus (GPa) as a function of draw ratio for polyester 4,4 -0 = 0.15 (nr. BB1) fibers. Spinning temp. = 300°C.

Polyester BB1 was run twice in steady mode at 290°C (Figure 10), and shows that the orientational effect of the first run has a drastic effect on steady shear viscosity. In the first run the log viscosity vs. log shear rate had a slope of -0.92 (solid like behaviour, yield stress), but in the second run a pseudo-Newtonian plateau was reached from approx. 1 sec 1. Capillary viscosity values corresponded reasonably well with the second run steady shear data. The slope at high shear rates was close to -0.91 which corresponds nicely to the first-run steady shear run. All this could suggest, that this system is not completely melted, but still has some solid like regions incorporated. At 300°C capillary viscosity data showed an almost pseudo-Newtonian plateau. This corresponds quite well to the fact that fiber spinning as mentioned earlier was difficult and almost impossible below 290°C, but easy at 300°C. At an apparent shear rate of 100 sec 1, a die-swell was found to be approximately 0.95. 

During the course of our study, we had the opportunity to evaluate the only available all aromatic, thermotropic polyester, LCP2000 from Celanese. Presumably it was a copolymer containing hydroxybenzoic (HBA) and hydroxy naphtholic acid (HNA) moieties. The sample was subjected to fiber spinnings and plastic moldings as were the thermotropic polyester-carbonates, using the same equipment and under comparable conditions. 

Pripol. [Unichema Unichema France SA] IMmer or trimer acids modifier for nylon, polyester fibers used in polyamide for hot melt adhesives, thermographic inks, urrfhane elastomers, industrial lubricants, fuel additives, surface coadng resins, spin finishes. 

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