Degumming and dyeing properties of cocoon filaments with a special feature differed from conventional silkworm races

1) The difference in degumming loss among silkworm races with special characteristics related to the cocoon filament could be detected even though the degumming experiments were carried out in the same bath. The cocoon filaments of polyphagous silkworms showed a high value for the degumming loss, while the fine cocoon filaments showed a low value. Also, the values of the degumming loss for the coarse and conventional cocoon filaments were larger than those for the fine cocoon filaments, but lower than those for the polyphagous silkworms. The difference in the degumming loss among silkworm races could not be readily determined due to the difference in the amount of sericin. Since residues of sericin could not be observed by scanning electron microscopy. 2) the amount of dye adsorbed onto "Habataki", "Asagiri", "Shin-asagiri" varieties, increased with the increase of the dye concentration, that is fibers of these varieties were well suited to highly concentrated dyeing. Grains of the staining compounds could infiltrate silk filaments more easily than in other varieties such as "Kinsyu x Showa" and "Asahi x Tokai", suggesting that "Asagiri" and "Shin-asagiri" fibers are more widely spaced than those of other varieties. 3) Although the same amount of dye was adsorbed, the color of the fine fibers was lighter than that of the coarse ones. Therefore, to obtain the same color, 10-20% more dyestuff must be adsorbed. As a result, 20-30% more dye should be used for fine fibers compared with coarse fiber. 4) There were no differences among the varieties in the number of sites onto which the dye could be adsorbed. thus the difference in the unevenness of dye adsorption between fine and coarse fibers depended on the difference in the microstructure, which is related to dye diffusion and not on the number of sites, diffusion coefficient of dye to intra-fiber space of coarse fibers was larger than that of fine ones