The mechanism of carrier dyeing

Abstract

synopsisThe accelerated rate of diffusion of disperse dyes into synthetic fibers caused by various dyebath additives ("carriers") has been correlated with their plasticizing action. The rate of change in length of Acrilan filaments with temperature under dyebath conditions enabled the effects of the carrier on the To of the filaments to be measured, and the results for different concentrations of carrier a t one temperature could be superimposed on a common curve by employing suitable shift factors. The shift factors, BS well as the variations of the diffusion coefficients of dyes with temperature and carrier concentration, bothmatched a WLF relationship, confirming that the dyeing process is controlled by the segmental mobility of the polymer. Indirect experimental evidence suggests that the same relation will describe the effect of carriers on the dyeing of poly(ethy1ene terephthalate) substrates with disperse dyes. INTRODUCTIONEarlier diificulties associated with the coloration of synthetic fibers made from polyacrylonitrile and poly(ethy1ene terephthalate) , using nonionic dyes, were due to the unacceptably slow rate of diffusion of the dyes into the fiber. These practical problems were eventually overcome by applying the dyes in specially developed pressurized machines which operate at temperatures greater than 100°C, or by the addition to the dyebath of organic compounds such as phenols, primary amines, hydrocarbons, and esters, which have the effect of increasing the rate of diffusion of the dyes in the fibers to an acceptable level of temperatures below 100°C. The latter compounds are referred t o as "carriers" and their mode of action is discussed in this report.Various aspects of the action of "carriers" have already been examined in an attempt to elucidate the mechanism by which they operate and various theories have been put forward. Some workers' suggest that the enhanced rate of dyeing is a result of an increase in the low solubility of the disperse dyes in the dyebath, while others2 claim the action of water-insoluble carriers to be due to the formation of a surface layer of carrier around the fiber in which the dye is very soluble and from which movement into the fiber is rapid due to the intimate contact between dye and fiber.It has also been noted that some carriers cause swelling of the fibers, and this leads to the theory that a more vigorous movement of the fibrous 3733

New disperse dyeing method of poly(p-phenylene benzobisoxazole) fiber pretreated with polyphosphoric acid

“…But, the negative effect of the carrier dyeing on supramolecular structure was very limited, which was similar to the pretreatment of PBO fiber by polyphosphoric acid [14]. And the results were also consistent with the classical theory of the carrier dyeing [16,18,26,41,42].…”

“…Salvin [17] postulated that carriers replace fiber-fiber interactions with more readily breakable fiber-carrier bonds, which can sequentially permit the polymer chain to move easily and promote more free volume available in the fiber. As a result, the glass transition temperature (T g ) and dyeing transition temperature (T d ) of the fiber may be expected to be decreased during the carrier dyeing process, and the diffusion rate of dyes and the dye exhaustion to be increased [18,19]. Therefore, carriers could be used in the coloration of synthetic fiber, for example, for acrylic, PVC and polyphenylene sulfide fibers with cationic dyes [19][20][21][22][23], and for polyester and triacetate fibers with disperse dyes [24][25][26].…”

Polyvinylamine application for functionalization of polyethylene fiber materials

“…It is supposed that the carriers enhance the swelling of the fibers. By this physical effect on the fiber they enable the easier penetration of hydrophobic compounds into the fiber matrix (Ingamells, Peters, & Thornton, 1973). The application of recipe 2 containing the carrier substance Sarapol is used to investigate if a carrier can support the application process positively and also with the aim to realize lower process temperatures (Figure 7).…”

Thermal analysis in industrial environments

“…Of practical interest was the effect of "carriers" -additives to the dyebath which are used to accelerate the rate of dye diffusion within the hydrophobic fibers. The mechanism by which these materials enhance dye uptake is thought to be by plasticizing the fiber, thus increasing the segmental mobility of the polymer chains [9]. Figure 4 shows the enhancement in dye uptake that can be achieved by incorporating various carriers into the dyebath.…”