Disperse dyes fixing

Disperse—Vat Combinations. These require a two-step fixation. The disperse dye is fixed first, usually by dry heat, followed by impregnating of the textile with an alkaU and reducing agent solution and short steam fixation for the vat dye. The selected disperse dyes fixed in the polyester fiber are not destroyed by the reducing agent, but disperse dye remaining on the cellulose is destroyed. 

Biomass from an anaerobic digester Reactive dyes disperse dyes Fixed bed with recycle and fixed bed Continuous Anaerobic B Reticulated sintered glass n.a. 37 6.4-7.2... 

Pahmfl . [BASF BASF AG] Disperse dyes fix pdyester, acetate, triacetate, nykxi, polya lonitrile, PVC pedyvi-nyl alc l fibm. 

Thermosol dyeing. The characteristics of low-molecular-weight polyester dyes can be utilized in thermosol dyeing processes. In this continuous dyeing process the material is impregnated with the dispersed dye, dried, and heated to a temperature of approximately 200-210°C. The dyestuff is fixed by sublimation into the fiber. 

Fixation is performed by steaming under various conditions, depending on the fibers and dyes involved. Generally, saturated steam at ca. 100°C is applied. Pressure steamers permit a reduction of the steaming time. Disperse dyes are fixed in polyester fibers by the Thermosol process the fabric is heated in a infrared unit by radiation, by hot air, or with contact heat to 210-220°C for 30-60 s. Superheated steam facilitates rapid fixation at lower temperatures. 

In heat fixation of disperse dyes, hot air and contact heat are used most commonly. Steam has a swelling effect on the fiber. If superheated steam is used for fixation, the temperature can be lowered in comparison with hot air, the fixing times being the same. This is an advantage especially with articles made of textured fibers. 

In the case of PES-CEL fiber blends, the larger part of the liquor is absorbed by the CEL fiber during drying, because of its higher absorption capacity. Nevertheless, in the subsequent thermofixing step, disperse dyes are almost completely fixed to the PES fiber. Transfer from the CEL to the PES fiber occurs both by migration via direct fiber contact and through the gas phase. The type of transfer depends on the sublimation behavior of the dyes [120],... 

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. 

The chemistry of these polysaccharides is dominated by partial esterification of the total number of carboxyl groups. The sequence of uronic acids in the primary structure is occasionally interrupted by rhamnose, and there is usually a trace of acetyl and phenolic substituents. Models developed from experimental data considered neutral side chains with DP = 2-10 (De Vries et al., 1982). These 1,4-a-linked linear uronans are susceptible to alkali—more so if the C-6 hydroxyl is esterified, but exceptionally acid-stable when this site is unsubstituted. Dispersion stability is less at higher DP. Uronans are endowed with strong dye-fixing and mineral-sequestering properties because of their charged surface. 

Dyeing is normally readily accomplished in aqueous solution, often in the presence of a fixing agent, or mordant. This is ideal for cotton, silk and wool, but not for certain synthetic fibers, such as nylon and polyester. The latter are plastic in nature, and require disperse dyes. Here the dyeing process involves heating the fiber in an aqueous dispersion of a water-insoluble dye. A solid solution is formed in the fiber. In order to penetrate synthetic fibers, a small dye molecule is required, for which simple water-insoluble mono-azo dyes are ideal. Apart from yellow dyes (where phenolic components are common), these are usually based on /V,/V-dialkylated aniline coupling components that permit a wide range of shades to be obtained. 

Chemtherm AM. [Chem-Tex Labs] Pdlymeric antimigrator fix use in continuous dyeing of cotton and polyester with vats, sulftir, direct, and disperse dyes. 

Amsperse 109. [Am. Emulsions] Dispersing assistant fix disperse dyes. 

Disperse Dyes Nonionic dyes insoluble in water and used mainly as fine aqueous dispersions in dying acetate, polyester, and polyamide fibers. A large subclass of disperse dyes comprises low-molecular-weight aromatic azo compounds with amino, hydroxy, and alkoxy groups that fix on fibers by forming van der Waals and hydrogen bonds. 

Disperse dyes can also be applied indirectly as a transfer from paper that has been printed with the pattern using an ink jet printer charged with the disperse dye. A heat press, available in various flatbed or roll-to-roll formats, is aptly named, applying both heat and pressure to a substrate. This method fixes or cures the ink as part of the... 

Several types of dyes or colorants do not "fit" logically into the other classifications and have been included in this special classification. Disperse dyes are small polar dye molecules which can be used to dye thermoplastic fibers such as triacetate, nylon, polyester, and other synthetic fibers. Solvent dyes are dyes which are specially formulated so that they can be applied from solvents other than water. Pigments are not dyes at all, but rather colorants that must be incorporated in the fiber during spinning or fixed on the surface of the fiber by use of a polymer adhesive. Natural dyes are complex mixtures derived from natural sources which can be placed in a number of the above classifications. 

Uses Dye fixing agent for paper industry dispersant for dyes in papennaking stabilizer for rosin size emulsions in papermaking Features Water-based dye is retained even by bleached fibrous material with good yield... 

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