Dyes: application and evaluation

Standard polyester fibers contain no reactive dye sites. PET fibers are typically dyed by diffusiag dispersed dyestuffs iato the amorphous regions ia the fibers. Copolyesters from a variety of copolymeri2able glycol or diacid comonomers open the fiber stmcture to achieve deep dyeabiHty (7,28—30). This approach is useful when the attendant effects on the copolyester thermal or physical properties are not of concern (31,32). The addition of anionic sites to polyester usiag sodium dimethyl 5-sulfoisophthalate [3965-55-7] has been practiced to make fibers receptive to cationic dyes (33). Yams and fabrics made from mixtures of disperse and cationicaHy dyeable PET show a visual range from subde heather tones to striking contrasts (see Dyes, application and evaluation). 

Dyes, application and evaluation). Foi dyeing fibei blends such as viscose—polyamide, polyamide—Spandex, oi polyestei—cotton, only compatible FWAs may be used that do not inteifeie with one another oi have any detrimental effect on fastness properties. 

From an appHcations point of view, the sulfur dyes are between vat, direct, and fiber-reactive dyes. They give good to moderate lightfastness and good wetfastness at low cost and rapid processing (see Dyes, application and evaluation). 

Stannic chloride is also used widely as a catalyst in Eriedel-Crafts acylation, alkylation and cycHzation reactions, esterifications, halogenations, and curing and other polymerization reactions. Minor uses are as a stabilizer for colors in soap (19), as a mordant in the dyeing of silks, in the manufacture of blueprint and other sensitized paper, and as an antistatic agent for synthetic fibers (see Dyes, application and evaluation Antistatic agents). 

Organic colors caused by this mechanism are present in most biological colorations and in the triumphs of the dye industry (see Azinedyes Azo dyes Eluorescent whitening agents Cyanine dyes Dye carriers Dyes and dye intert diates Dyes, anthraquinone Dyes, application and evaluation Dyes, natural Dyes, reactive Polymethine dyes Stilbene dyes and Xanthenedyes). Both fluorescence and phosphorescence occur widely and many organic compounds are used in tunable dye lasers such as thodamine B [81-88-9], which operates from 580 to 655 nm. 

---