セグメントポリウレタンにおけるソフトセグメント成分の変化に伴う染色性の変化

Abstract

The aim of this study is to clarify the dyeing behavior with acid dyes in the segmented polyurethanes with soft segments composed of various ratios of PTMG and PEG components by measuring the dye uptake. Experiments revealed that the higher ratio of PEG component resulted in increasing the hydrophilic property and decreasing the aggregate structure in the segmented polyurethanes. Aqueous dyeing solution, consequently, seemed to adsorb positively into the intra-molecules of polyurethanes.Considering the stress-strain relations and water-swelling characteristics of polyurethane films, the dye affinities of the films before and after dyeing were evaluated. After dyeing, the segmented polyurethane films seemed to losing hydrogen-bonding ability resulting in making the aggregate structure small. It was suggested that the dyestuff molecules were adsorbed in the hard segments of the polymers with some form of bonding.Furthermore, it was observed that the dye adsorption for CI Acid Red 114 was higher than that for CI Acid Red 37 among two kinds of acid dyes applied in this study. It was suggested as follows: (1) CI Acid Red 114 having bulky molecular structure against CI Acid Red 37, ca. 1.6 times in molecular weight, contributed to adsorb into the segmented polyurethanes with van der Waals forces. (2) CI Acid Red 114 molecule modified with formic acid in dyeing bath changing to insoluble form for water adsorbed easily onto the hydrophobic group of the segmented polyurethanes.