Abstract
The influence of the chemical constitution and H. L. B. value of non-ionic surfactants upon the diffusion distribution of a direct dye in the cellulosic material was studied and carried out by means of the cellophanefilm roll method.
Purified Direct Fast Red F (C. I. Direct Red 1) was used throughout the entire experiment. Eighteen non-ionic surfactants, which are classified as P. E. G.-Octylether type (I), P. E. G.-Nony-lphenylether type (II), P. E. G.-Oleylether type (III), P. E. G.-Oleylester type (IV), and P. E. G.-alkyl (C16-18) amine type (V), were employed. Each of these types contains various number of moles of ethylene glycol.
From the data obtained the retarding action of these surfactants in direct dyeing is discussed below:
1) (I) shows a little retarding effect irrespective of the value of H. L. B.; i.e. the surface dye concentration Co is not appreciably altered or decrease.
2) (II), (III) and (IV) show increasing retarding effects with increased H. L. B. values.
3) (V) shows considerable retarding effects even at small H. L. B. value.
The general structure of a non-ionic surfactant may be considered as composed of the three constituent groups, namely: (1) the hydrophobic group, (2) the hydrophilic group, and (3) the bridge. To show adequate retarding effects, the non-ionic surfactants should have a suitable hydrophobic group (as nonylphenol-or oleyl-group), and a suitable hydrophilic group (as 15-25 moles of ethylene glycol linkage), and the bridge of these two groups must be either of ether or ester type.
