Dyeing textile fibers rayon

Azoic dyes. Azo dyes contain at least one azo group (—N=N—) attached to one or often two aromatic rings. They are produced in textile fibers (usually cotton, rayon, and polyester), by diazotization of a primary aromatic amine followed by coupling of the resulting diazonium salt with an electron-rich nucleophile (azo coupling). A variety of hues can be obtained... 

The world textile industry is one of the largest consumers of dyestuffs. An understanding of the chemistry of textile fibers is necessary to select an appropriate dye from each of the several dye classes so that the textile product requirements for proper shade, fastness, and economics are achieved. The properties of some of the more commercially important natural and synthetic fibers are briefly discussed in this section. The natural fibers may be from plant sources (such as cotton and flax), animal sources (such as wool and silk), or chemically modified natural materials (such as rayon and acetate fibers). The synthetic fibers include nylon, polyester, acrylics, polyolefins, and spindex. The various types of fiber along with the type of dye needed are summarized in Table 8.2. 

Camille and Henry Dreyfus developed the first commercial process to manufacture cellulose acetate in 1905 and commercialized the spinning of cellulose acetate fibers in 1924 in the United States. At that time, the only other human-made fiber was viscose rayon, which was still in its early stages of commercialization. The main textile fibers were natural fibers cotton, wool, silk, and flax. Cellulose triacetate textile fiber was commercialized later in the 1950s. The tremendous technical effort by the Dreyfus Brothers resulted in more than 300 patents describing such significant inventions as the dry-spinning process and disperse dyeing. 

P.R.170 is not always heat stable enough to allow application in polyolefins. In HDPE systems formulated at 1/3 SD, the pigment tolerates exposure to 220 to 240°C for one minute. Its tinctorial strength, on the other hand, is excellent. P.R.170 is also occasionally used in polypropylene and polyacrylonitrile spin dyeing in the latter medium, it satisfies the specifications of the clothing and home textiles industries. Besides, P.R.170 lends color to viscose rayon and viscose cellulose it is used for the mass coloration of semisynthetic fibers made of cellulose last but not least, it colors yarns, fibers, and films made of secondary acetate. 

Uses Manufacture of acetate rayon, acetic anhydride, acetone, acetyl compounds, cellulose acetates, chloroacetic acid, ethyl alcohol, ketene, methyl ethyl ketone, vinyl acetate, plastics and rubbers in tanning laundry sour acidulate and preservative in foods printing calico and dyeing silk solvent for gums, resins, volatile oils and other substances manufacture of nylon and fiber, vitamins, antibiotics and hormones production of insecticides, dyes, photographic chemicals, stain removers latex coagulant textile printing. 

Magnesium acetate is used in the manufacture of rayon fiber for cigarette filters and as a fixative for dyes in textile printing. It also is used as an antiseptic and disinfectant. 

Due to the potential regression in supply and use of disazo directs and vats as well as more strenuous wet fastness requirements, textile firms dyeing cotton-containing fabrics are projected to switch production to reactive dyes in increasing numbers. Reactive dyes are unique in that the dye with the cellulose in cotton or rayon. In the process the material is impregnated with the reactive dye, base is added to the bath to effect the dye/fiber chemical reaction, and the fabric is then carried through an afterscour. Reactive dyes have several severe drawbacks ... 

Is a moderately lipophilic emulsifier and lubricant. It is used as a co-emulsifier for metalworking oils and hydraulic fluids. In textiles it is used as a component in leveling and dispersing agents for vat and naphthol dyes, and as a co-emulsifier for rayon delusterants and fiber lubricants. HLB 8.6... 

The textile industry is characterized by a host of journals that are marginal in the sense that they contain a little bit of everything. For example, Modern Textiles Magazine (46) y formerly known as Rayon and Synthetic Textiles usually contains some articles on fairly fundamental research in man-made fibers or textiles. Besides this, the journal contains at various times articles for mill operating personnel, articles on dyeing, production and consumption statistics, articles on new equipment, yarn prices, and similar material that could be of interest to almost anyone in the industry. 

In certain cases, identifying the specific garment or textile product and the allergen it contains will be an important undertaking. The fiber content of the fabric will narrow the possible dyes, as certain dyes are used to color certain fibers. Cotton, rayon, and linen fabrics are dyed with direct, fiber-reactive, mordant, azoic, sulfur, and vat dyes. Wool fabrics are dyed with acid, mordant, and fiber-reactive dyes. Polyester fabrics are dyed with disperse dyes unless the polyester is modified to accept basic dyes. Nylon fabrics are colored with acid and disperse dyes unless modified to accept basic dyes. Acrylic fabrics are dyed with basic and disperse dyes. Acetate fabrics are dyed with disperse dyes. Other synthetic fibers are dyed with disperse dyes. 

Dyes, Vat n A class of water-insoluble dyes which are applied to the fiber in a reduced, soluble form (leuco compound) and then reoxidized to the original insoluble form. Vat dyes are among the most resistant dyes to both washing and sunlight. They are widely used on cotton, linen rayon, and other cellulosic fibers. (Tortora PG (ed) (1997) Fairchild s dictionary of textiles. Fair-child Books, New York)... 

---