Triacetate fibers

The predominant cellulose ester fiber is cellulose acetate, a partially acetylated cellulose, also called acetate or secondary acetate. It is widely used in textiles because of its attractive economics, bright color, styling versatiUty, and other favorable aesthetic properties. However, its largest commercial appHcation is as the fibrous material in cigarette filters, where its smoke removal properties and contribution to taste make it the standard for the cigarette industry. Cellulose triacetate fiber, also known as primary cellulose acetate, is an almost completely acetylated cellulose. Although it has fiber properties that are different, and in many ways better than cellulose acetate, it is of lower commercial significance primarily because of environmental considerations in fiber preparation. 

Fig. 5. The effect of dry heat exposure on acetate and triacetate fibers. Tested at 65% rh, 21°C after exposure. A, acetate, 100°C B, triacetate, 130°C and C,...

The ratio of stress to strain in the initial linear portion of the stress—strain curve indicates the abiUty of a material to resist deformation and return to its original form. This modulus of elasticity, or Young s modulus, is related to many of the mechanical performance characteristics of textile products. The modulus of elasticity can be affected by drawing, ie, elongating the fiber environment, ie, wet or dry, temperature or other procedures. Values for commercial acetate and triacetate fibers are generally in the 2.2—4.0 N/tex (25—45 gf/den) range. 

Table 2. Tenacity and Elongation of Commercial Acetate and Triacetate Fibers...

Acetate and triacetate exhibit moderate changes in mechanical properties as a function of temperature. As the temperature is raised, the tensile modulus of acetate and triacetate fibers is reduced, and the fibers extend more readily under stress (see Fig. 4). Acetate and triacetate are weakened by prolonged exposure to elevated temperatures in ah (see Fig. 5). 

Chemical Properties. Under slightly acidic or basic conditions at room temperature, acetate and triacetate fibers are resistant to chlorine bleach at the concentrations normally used in laundering. 

Acetate and triacetate are essentially unaffected by dilute solutions of weak acids, but strong mineral acids cause serious degradation. The results of exposure of heat-treated and untreated triacetate taffeta fabrics to various chemical reagents have been reported (9). Acetate and triacetate fibers are not affected by the perchloroethylene dry-cleaning solutions normally used in the United States and Canada. Trichloroethylene, employed to a limited extent in the UK and Europe, softens triacetate. 

Resistance to Microorganisms and Insects. Resistance of triacetate to microorganisms, based on soil-burial tests, is high, approaching that of polyester, acryUc, and nylon fibers. Sod-burial test results on acetate, triacetate, and cotton are shown in Figure 8. Neither acetate nor triacetate fiber is readdy attacked by moths or carpet beedes. 

CeUulose triacetate is insoluble in acetone, and other solvent systems are used for dry extmsion, such as chlorinated hydrocarbons (eg, methylene chloride), methyl acetate, acetic acid, dimethylformamide, and dimethyl sulfoxide. Methylene chloride containing 5—15% methanol or ethanol is most often employed. Concerns with the oral toxicity of methylene chloride have led to the recent termination of the only triacetate fiber preparation faciHty in the United States, although manufacture stiH exists elsewhere in the world (49). 

Fig. 11. World production of cellulose acetate and triacetate fibers I, cigarette tow B, textile (74).

Textiles. A unique combination of desirable quaUties and low cost accounts for the demand for acetate ia textiles. In the United States, acetate and triacetate fibers are used ia tricot-knitting and woven constmctions, with each accounting for approximately half the total volume. This distribution changes slightly according to market trends. The main markets are women s apparel, eg, dresses, blouses, lingerie, robes, housecoats, ribbons, and decorative household appHcations, eg, draperies, bedspreads, and ensembles. Acetate has replaced rayon filament ia liner fabrics for men s suits and has been evaluated for nonwoven fabrics (79—81). 

Triacetate offers better ease-of-care properties than secondary acetate ia many apparel appHcations. Of particular importance are surface-finished fabrics, eg, fleece, velour, and suede for robes and dresses. These fabrics offer superb aesthetic quaHties at reasonable cost. Triacetate is also deskable for print fabrics, where it produces bright, sharp colors. The recent discontinuance of triacetate fiber Hi the United States has led to the use of acetate with fibers such as polyester (47—50). 

Rejection Rejection is defined in Background and Definitions. The highest-rejection membranes are those designed for single-pass production of potable water from the sea. The generally accepted criterion is 99.4 percent rejection of NaCl. Some membranes, notably cellulose triacetate fibers are rated even higher. A whole range of membranes is available as rejection requirements ease, and membranes with excellent chlorine resistance and hydrolytic stability can be made with salt rejection over 90 percent. 

Tri (rt-butyl)phosphate (TBP), 79 674 Tri-l,10-phenanthroline-iron(II), 7 589 1-Triacontanol physical properties of, 2 3t cis-21-Triacontenoic acid physical properties, 5 32t Triacetate chiral stationary phase, 6 88t Triacetate fibers, 24 614 Triacetone amine... 

Acetate fiber is the generic name of a fiber that is partially acetylated cellulose. They are also known as cellulose acetate and triacetate fibers. They are nontoxic and generally non-allergic, and so are ideal from this aspect as clothing material. 

Gibbs, G.W., Amsel, J. Soden, K. (1996) A cohort mortality study of cellulose triacetate-fiber workers exposed to methylene chloride. J. occup. environ. Med., 38, 693-697... 

It has already been implied that cellulose triacetate will not produce a thermoplastic, as its softening point cannot be reduced appreciably by plasticizers. It is used in solution processes, however, to produce films and libers. Triacetate films absorb less water than films of secondary cellulose acetate, and they arc therefore more dimensionally stable in environments where the humidity is not controlled. Triacetate fibers, with a similar resistance to water, impart to fabrics wrinkle resistance, dimensional stability, and the ability to dry rapidly. Under United Slates federal regulations, a filler must tic made from a cellulose acetate having... 

Absorption and Smelting Behavior. The absorption of moisture hy acetate and triacetate fibers generally depends on the relative humidity and whether equilibrium is approached from the dry or wci side. The percentage of moisture regain of commercial libers (ASTM Dl909-681. taken at 65% relative humidity for the ahsorplion cycle, is 6.5 lor acetate liber and 3.5 for triacetate. Heat treatment catt lower the ninislure regain of triacetate fiher. and values of 2.5-3.2% have heen observed. 

Dyeing Characteristics. Disperse dyes, high melting crystalline compounds w ith low solubility in the dye hath, are most frequently used for cellulose acelate and triacetate fibers. 

Triacetate fiber is significantly mote resistant than acetate to alkalies encountered in normal textile operations,... 

Cellulose Acetate and Triacetate Fibers. Polymer solutions arc convened into fibers by extrusion. The dry-extrusion process, also called dry spinning, is primarily used lor acelate and triacetate. 

Other Fibers. The main products used for cellulose acetate or triacetate fibers are pyrazoline derivatives such as 49-51, and for wool typical polyamide brighteners. 

Dye for polyesters, polyamides, 285 cellulose, and triacetate fiber yellow or reddish yellow shade... 

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