Disperse Dyes see Section

Disperse dyes of the azo and anthraquinone types, on the other hand, are used in hair tints. They also give annular color patterns, which are relatively durable because of the poor solubility of the dyes in aqueous systems. They can be combined with other classes of dyes. 

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Solvent dyes [1] cannot be classified according to a specific chemical type of dyes. Solvent dyes can be found among the azo, disperse, anthraquinone, metal-complex, cationic, and phthalocyanine dyes. The only common characteristic is a chemical structure devoid of sulfonic and carboxylic groups, except for cationic dyes as salts with an organic base as anion. Solvent dyes are basically insoluble in water, but soluble in the different types of solvents. Organic dye salts represent an important type of solvent dyes. Solvent dyes also function as dyes for certain polymers, such as polyacrylonitrile, polystyrene, polymethacrylates, and polyester, in which they are soluble. Polyester dyes are principally disperse dyes (see Section 3.2). 

For the theoretical aspects of dyeing CA and CT with disperse dyes see Section 4.12.1. CA is dyed by the exhaustion method in the presence of a nonionic or anionic dispersing and leveling agent in a weakly acidic bath (pH 5-6). A series of less wetfast disperse dyes are taken up by acetate at temperatures as low as 50-60 °C. For this reason, the process must be started at a correspondingly low temperature to obtain level dyeings. Dyeing is normally done at 80-85 °C. Dyes... 

The mechanical properties of PETP fibres are dictated by the amount of cold drawing of the amorphous fibre—the longer the draw the higher the crystallinity and tensile strength developed. PETP fibres are dyed almost exclusively using dispersed dyes (see section 2.4.2.4). For permanent press polyester/cotton apparel, the press is obtained by treating the material with UF resin (i.e. only the cotton fibre is modified). 

The synthesis of monoazo disperse dyes by diazotization and coupling is described under Azo Dyes (see Section 2.2). Additional chemical treatment subsequent to synthesis of the azo compounds is performed only rarely. 

More than 50% of disperse dyes are simple azo compounds, about 25% are anthraquinones, and the rest are methine, nitro, and naphthoquinone dyes (see Sections 2.2, 2.3, 2.6, 3.12). 

In dyeing PES-CEL mixtures, disperse dyes are used for the PES component. The CEL portion can be dyed with practically all classes of dyes suited to cellulose (see Sections 4.2-4.8). The selection of suitable dyes depends not only on the equipment available, the desired shade, and the batch size, but also on economic factors, with the required fastness taken into account. Thus, reactive dyes (see Section 4.2) are used preferentially for all types of clothing textiles, but vat dyes (see Section 4.4) are employed where extreme demands are made on washfastness or weatherproofness. 

With regard to heterocyclic compounds as coupling components, the importance of the formerly widespread pyrazolone-, aminopyrazole-, and 4-hydroxy -quinolone-based yellow azo dyes has greatly diminished with the advent of the tinctorially superior and therefore more economical pyridone azo dyes. Only a few examples have survived and then only for special applications such as for dyeing of acetate fibers. Examples are C.I. Disperse Orange 56 and C.I. Disperse Yellow5. (for structure, see Section 3.2.5). 

Pad Roll Process (see Section 4.1.1). Disperse dyes are fixed only incompletely to PES fibers under the conditions of the pad roll process (padding and subsequent rotation of the batch in saturated steam atmosphere). Only light colors can be produced economically with adequate fastness. Carrier additions are not useful because very large amounts would be required. In the pad roll process, rapidly diffusing dyes must be used. 

Disperseand Sulfur Dyes (see also Section 4.7.3). The thermosol pad steam process is the primary method for application of disperse and sulfur dyes. The sulfur dyes that are used preferentially in the ready-for-dyeing soluble form, and are especially inexpensive for muted shades, must be applied after the thermosol step because of their incompatibility with disperse dyes. 

DisperseDyes and Leuco Esters of Vat Dyes (see also Section 4.5). If a thermosol passage is provided under conditions that cleave the ester, so that the vat acid can diffuse into the PES fiber, leuco esters of vat dyes can produce up to medium shades with a high fastness level without the additional use of disperse dyes. 

Wool is stained less at high temperatures and longer dyeing times because the disperse dye that was initially on the wool component migrates to the PES fiber. Carrier-free dyeable PES fibers should preferably be employed these fibers are easily dyeable even at boiling temperature (see Section 4.12.2). The nature of the wool also plays a role, fine wool and reclaimed wool being more strongly soiled. 

Disperse dyes can be used to produce light to medium deep shades on acrylic and modacrylic fibers [96, p. 639], The dyeing mechanism and process correspond to those used on PES and CA fibers (see Section 4.12). However, dyeing can be performed below 100°C. Addition of carriers is not required. The good migration properties of disperse dyes result in problem-free level dyeing. 

Modacrylic fibers can also be dyed with disperse dyes, similarly to normal PAC fibers, but the fastness to sublimation is poor (see Section 4.13.3). 

Even more sensitive than these staining tests for detecting grease and oil contamination is an imprint on thermoplastic films (see Section 8.4.6). During production of the imprint, hydrophobic deposits diffuse into the film and can usually be easily recognized by the local cloudiness they cause. The natural waxes of cotton do not interfere here because they are evenly distributed. Spots caused by pigments or disperse dyes are also transferred onto the film imprints and are then easier to investigate microscopically. ... 

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