Dyes for the Hydrophobic Fibers1

Abstract

The commercialization of the hydrophohic fibers has necessitated the development of entirely new classes of dyes. This job has been accomplished successfully by the careful tailoring of dye molecules to the chemical and physical requirements of the different fibers.All of the hydrophobic fibers designed for apparel use can be dyed with disperse dyes. Polyamide and acrylic fibers can be dyed with acid dyes. Selected acrylic fibers can be dyed also with basic dyes. The dyeing of hydrophobic fibers with disperse dyes involves solution of the dye in the fiber : electrostatic interactions are involved in the dyeing of these fibers with ionic dyes. The rate of dyeing with both the disperse and the ionic dyes is largely a function of the specific fiber and the molecular size and geometry of the dye molecules. The polarity of a disperse dye plays a major role in determining the affinity of the dye for a specific fiber.Resistance of both the disperse and the ionic dyes to removal from the fiber by aqueous treatments is directly proportional to the affinity of the dye for the fiber and inversely proportional to the rate of dyeing. The washing fastness of the extremely hydrophobic fibers is excellent with all of the dyes which are applicable.The photochemical decomposition of a dye on a fiber is a reaction of the electronically excited dye molecule with the fiber and or other elements of the environment. Hence, light-fastness is a characteristic of the particular dye fiber system. Many correlations of affinity and fastness properties with molecular structure can be drawn.i w E plan to summarize the present status of the (1%-eitig of the hyclrcy>lu~l~ir wnth··tir filx·r,. ~~'hile our emphasis will he on the newer acrytic and polyester nhers. a clearer understanding of the overall devetoptnent is possihte from a simuttaneons consideration of celitilose acetate and the nylon polyamides,------L ntit the advent of the new synthetic fibers, dyeinK involved almost exclusively water-solultle colors. These colors dyed hy a process of ahsurption where the tllwr and dye showed an attraction, or affinity, for each other. The chenncat reactions involved either salt formation between dye ions and ionized filter, as in the case of wool. or intermotecutar assodations, as in the case of cellulose.

Part II ‐ Colour, Dyeing and Fastness Properties of some 4‐Amino‐β, β‐dicyanostyrenes and Ethyl‐α‐cyano‐4‐aminocinnamates

“…The effect was fairly small on nylon, but was very marked on other fibres, e.g., compare dyes 11.5, 11.9 and 11.10 on triacetate. This decrease in light fastness with introduction of N-0-hydroxyethyl groups has been observed in other dye classes [3, 14,15], but exceptions have been reported [ 161.…”

Studies of novel monomeric and polymeric azo disperse dyes

“…Disperse dyes sublime because they are devoid of ionic solubilizing groups and therefore have a significant vapor pressure at the temperature encountered in processing. It has been observed that the vapor pressure of a dye is inversely proportional to its molecular mass and its polarity 30. Some general trend might, therefore, be expected between the sublimation fastness of disperse dyes and their molecular weight and/or the introduction of polar groups into the dye structures.…”

Dyeing with Disperse Dyes

“…The dye transfer to the fibre from the micelles. As micelles empty their dye, they re-from and dissolve more dye from the solid particles (Ingamells, 1993) Much of the evidence that is available on the subject suggests that in dyed polyester fibres the disperse dyes are present chiefly in the monomolecular state [Schroeder & Boyd, 1957;Hoffman et al, 1968]. At the end of the dyeing process, the dye that has been absorbed by the fibre is in a state of dynamic equilibrium with the dye that remains in the bath, and the fraction of the latter that is in aqueous solution must be present in the same state of aggregation as the dye in the fibre.…”