INFLUENCES OF HYDROPHOBIC GROUPS ON THE FASTNESS TO WASHING OF RAYON FIBERS DYED WITH CATIONIC DYES

Abstract

In a series of our studies on improvement of dyeing properties of rayon by the introduction of hydrophobic urethane groups, this study concerns how the fastness to washing is influenced by the modification.
The affinities and the diffusion coefficients of four cationic dyes were measured using modified rayon fibers. The fastness was evaluated for the fibers dyed with the cationic dyes and with a disperse dye. The surface property of the modified rayon fibers was assayed by referring to the contact angles of water on cellophane films reacted with the urethanes.
The conclusions obtained are summarized as follows:
1. The enhancement of the affinities of the dyes to the modified fibers improves the fastness considerably.
2. The modification results a sizable reduction in the rates of diffusion of the dyes.
3. The enhanced hydrophobicity of the surface of modified rayon scarcely improves the fastness.