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Polyester fibers are dyed to a considerable extent by selected low-molecular  vat dyeswith satisfactory fastness properties. They can be applied on CEL±PES fiber blends by the Thermosol process. Vat dyes are used for PA±CEL blends when the highest possible wetfastness is required . The coloring strength on the PA component depends on the type of PA fiber and on dyeing conditions (the depth of shade on PA 6 is deeper than on PA 66). The lightfastness of some vat dyes can be lower on PA than on cellulose fibers. The advantage of using vat dyes is that in a single bath with selected products, dyeings of the same shade are obtained on both components. For instance, C.I. Vat Orange 26 [12237-49-9], C.I. Vat Blue 4, 69800 [81-77-6], C.I. Vat Blue 14, 69810 [1324-27-2], C.I. Vat Brown 55, 70905 [4465-47-8], C.I. Vat Blue 9,
C.I. Vat Blue 25, 70500 [6247-39-8] are widely applicable (in the exhaust and pad steam  process).  The  dye  yield  on  the  PA  component  increases  with  increasing temperature. With a dyeing time of 60 min, the most favorable temperature for the dyes mentioned above is 80±90 DC. The additives to the dyebath and the dyeing processes are the same as those used for dyeing cellulose fibers alone.

Reactive Dyes on Wool and Silk. Reactive dyes produce brilliant shade on wool with good fastness. They differ from reactive dyes for cellulose fibers because the reactivity of the chemoactive groups in wool is considerably higher than that of the hydroxyl groups in cellulose. To achieve level dyeing on  wool, dyes with reduced reactivity must be used, and an auxiliary agent added. Among the reactive groups in wool the most important are amino, imino, and hydroxyl groups. Reactions occur in a weakly  acidic medium (pH 3±5) and include nucleophilic substitution of leaving groups (usually Cl, F, and, rarely, sulfonate or ammonium groups) or addition reactions to polar aliphatic double bonds. Anchor groups  such as N-methyltaurine ethylsulfone and b-sulfatoethylsulfone have the advantage that their functional groups are masked at the start of the process; consequently, no premature reaction occurs below boiling temperature . At the same time, level dyeing is made possible by the increased solubility. Other dyes are bifunctional and can have a cross-linking effect on wool .
   In the acidic range, ionic bonds are formed between dye and fiber, and the dye is still capable of migration. At pH 5, covalent binding to the fiber predominates. In the dyeing process for wool, a nonionic or weakly cationic leveling agent is added to the liquor, and the pH adjusted to 3±4 with formic or acetic acid. The process is started at 40 DC, and after some time the pH is adjusted to 5±6 with sodiumdihydrogenphosphate. Dyeing is conducted at boiling temperature for 1 h.
   To eliminate hydrolyzed dye, an aftertreatment is performed at 80 DC with ammonia (pH 8.5±9.0). The last rinsing bath is weakly acidified. On silk, reactive dyes are only applied when brilliant shades are needed and when the colorfastness produced with acid dyes does not meet the required level . Dyeing is performed on silk with the addition of sodium sulfate. The system is heated up to 50±70 DC, and soda is added. Dyeing is completed at 70DC. An afterwash at 80 DC increases wetfastness.

For the continuous process, the materials must be carefully pretreated to guarantee rapid wetting and uniform absorption of liquor [5, pp. 254±264]. The padding liquor should contain an antimigration agent After dye application, the fabric is uniformly and gently dried to minimize migration of the insoluble dye, and the disperse dye is fixed in the PES component by the thermosol process . Subsequently, the  vat  dyes  on the CEL portion is developed either continuously according to the pad steam process or batchwise by the pad jig method. The most elegant method is pad steam development, which frequently follows the thermosol process in one pass. In pad steam development, the fabric is padded with reducing agent and alkali, and the vat dye is fixed by steaming in saturated steam (103±105 DC dry thermometer). Finely dispersed vat dyes must be used in this process because of the short vatting time.

  Disperse and Reactive Dyes. Reactive dyes are often used to dye the cellulose portion of PES±CEL blends because the coloring possibilities of  reactive  dyes  are  especially  diverse,  and  a  large  number  of relatively  easy application processes produce dyeings that are sufficiently fast for the clothing sector and, frequently, for household textiles. In the two-bath  batch method  the  PES component is predyed with  disperse dyes, and the CEL portion is topped with reactive dyes after reductive intermediate clearing, if necessary. In a one-bath two-stage batch process, the bath contains all the dyes from the start. After the PES component is dyed at 130 DC, the bath is cooled to ca. 80DC, and alkali is added to fix the reactive dyes to the CEL component. Careful selection of dyes is required because the reactive dyes must be stable at pH 4±5 and 130 DC.
  In a reverse process, the CEL component is predyed at alkaline pH, the pH is then lowered, and the PES component is dyed at 130 DC. In this case, alkali-stable disperse dyes must be chosen if the disperse dye is added at the start. In addition, large amounts of salt in the bath can interfere with dispersion stability. Hence, especially fast exhausting disperse dyes are used.

 Solvent dyes 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 .For practical reasons the different solubility can be used as a basis for a classification of solvent dyes, although there is no strict differentiation. Chemical constitution is defined here as a structure which meets the corresponding solvent requirements.

Vat dyes have been used for many decades to color cotton and other cellulose fibers. Despite their high cost and their muted colors, these dyes are extremely important for certain textiles because of their superior fastness. Very few new vat dyes have been developed over the past few years. Water-insoluble vat dyes are converted to soluble anthrahydroquinones by reducing agents, such as sodium dithionite (hydrosulfite) in the presence of sodium hydroxide. The sodium salts of these mostly deep colored  leuco compounds penetrate cellulose fibers. The insoluble dye is attached firmly to the fiber after  reoxidation . Representative of a special form are the water-soluble sulfuric acid esters of the anthrahydroquinone compounds, namely, the leuco esters of vat dyes. On the basis of their chemical constitutions the anthraquinoid vat dyes may be classified in the following major groups: acylaminoanthraquinones, anthraqui- noneazoles, anthrimides and other linked anthraquinones, anthrimidocarbazoles,

phthaloylacridones, benzanthrone dyes, indanthrones, and other polycondensed ring systems.

Disperse dyes are colorants with low water solubility that, in their disperse colloidal form, are suitable for dyeing and printing hydrophobic fibers and fabrics. Forerunners of the disperse dyes were the ionamine dyes of British Dyestuffs Corp.; these were N-methanesulfonic acids of aminoazo or aminoanthraquinone dyes that released the N-methanesulfonic acid group in the dyeing process and, thereby, precipitated as disperse dyes on the acetate fibers. The understanding of this mechanism in 1923 initiated the development of genuine disperse dyes. British Celanese and British Dyestuffs Corp. were the first companies to introduce these dyes into the market for coloring acetate fibers. The dyes were dispersed with sulforicinoleic acid, soap, or Turkey red oil.

Pure cotton yarn dyed the export of textiles in China, demand also increasing number is increasing day by day. With its various fastness reductionvat dyesin the advantage of comprehensive superior, all kinds ofdyes in the preferred position still. But cotton yarns reductive's dyeing is influenced by many factors, not improve ZhengPinLv even dye to domestic and foreign dyeing bound to a lot of trouble.

 Pretreatment

At present abroad used more enzyme hydrogen peroxide bleaching process using pectinase practice in certain pH value and temperature of nonionic add compatibility permeable agent, catalyst, slow granule and complexing agent to handle before. The primary cell wall cotton by removing. After degradation pectin Because in cotton fiber and cotton wax pectin, pectin between binding effect on removing cotton wax and easy after in the saponification and emulsification after removing. Cotton yarns pretreatment directly affect the dyeing effect often should check whether there when drilling cooked in born spot, macular, alkali spot, calcium spot; Bleaching whether to produce bleaching spot; Whether mercerizing defects such as silk flare produced illness. Cooking practice effect solely rely on capillary effect is not enough standard shall periodically inspection waxy substances, containing pectin containing nitrogen material and whether the residual stock material standards.

 Dyeing water

 Dyed water if hardness is taller, the hidden color reduction vat dyesbody sodium salt will and hard water formed the calcium, magnesium ions of insoluble calcium salt and magnesium salts, causing dyeing yarn dyed unevenness.

 Dyeing water softening method mainly have ionic rodman change resin softening method, alkali agent softening method and complexation softening method. If the factory does not have an ion exchange resin softening workshop, can use simple sodium hexametaphosphate complexation softening method to soften the dyed water.

After 20min cold treatment by hard become namely water softener.

Especially sensitive to calcium hardness reduction dyestuff is: reduction GCDN, BC RSN, blue: reduction orange yellow G reductive RRT; The hardness of magnesium reduction dyestuff is particularly sensitive: reduction orange 4R; Sulfur indigo colourful peach B, gn20-3b; Sulfur indigo riotous excess RRN; 3B, CNC slicer in BBK reduction colourful QingLian, ZR, 4R: reduction blue BC; Reductive colourful green B, FFB, ZG, 4G: reduction grey M, RRH; Reducing red brown GR.

130 dyeing equipment and operation

 Whatever cone yarn fluid flow dyeing machine or yarn hang cage fluid flow dyeing machine, often have to check the dyeing machine, pay attention to pump ji pump power, speed, wheel Angle, head, flow meets the requirements.

 Yarn lift Basic Dyes dyeing machine triangle roller section should be from every side 9cm roller 20cm. Speed fast into 30r/min. Slow to 15r/min set pieces for 10cm, quick place for 30 place/min, slow place for 15 place/min. Each packet 5kg) in the triangle of yarn (should possess 6 a roll 7 feet. Avoid yarn in the triangle roller on folded too thick or fiber bound. Triangle roller steering should be able to free control.