Kenichi Tanabe

STUDIES ON THE DYEABILITY OF VINYLON

Further experiment were carried out on the effects of formalization of vinylon under the various conditions of reaction, on the color-depths and color-shades of dyeings.Heat-treated polyvinyl alcohol fiber is formalized under various conditions of reaction and the color depths and the color-shades of dyeings, and dyed with direct-color and disperse-color were measured with the following results:As formalization proceeds the color-depths and color-shades of dyeings, dyed with direct-color, is generally found to increase initially and then decrease through maximum, on the other hand in the case the color-depth and color-shades of dyeings, dyed with disperse color, is improved with increase in degree of formalization.The better color-depths and color-shades at the same degree of formalization of dyeings, dyed with direct-color, are obtained, the more swellable to fiber the condition of reaction with the formalization without sodium sulfate. On the other hand, the color-depths and color-shades of dyeings, dyed with disperse-color, are unrelated to the condition of formalization.These results suggest that the deterioration of dyeing sites in the fiber decreases the degree of the color-depths and color-shades of the dyeing. This may be due to the variation in the existing state of dye in the fiber.

ON THE TENSILE RECOVERY OF FIBERS OF POLYVINYL ALCOHOL AND ITS DERIVATIVES

The relationship between tensile recovery and elongation is measured in various loading times, loads during recovery and recovering times with fibers of polyvinyl alcohol and its derivatives, silk, viscose rayon, acetate rayon and perlon L. From the tensile recovery-elongation curves these fibers are classified into three groups, e. g. cross-linkage type, side-chain type and steric hindrance type. Heat-untreated, heat-treated, and tere-phthalized polyvinyl alcohol fibers and perlon L are classified into the first type, formalized, butyralized, and nonalized fibers into the second type, and benzalized fiber, acetate rayon, silk, viscose rayon into the last type. In the cross-linkage type tensile recovery in higher elongation is better than that in lower elongation with the exception in very short loading time. In the steric hindrance type the minimum value in recovery-elongation curve rarely appears, and the effect of load during recovery and loading time for recovery are relatively small. The side-chain type shows the intermediate behavior between the other two types, but the effect of load during recovery is the greatest.

ON DYEABILITY OF FORMALIZED PRODUCTS OF POLYVINYL ALCOHOL

ON DYEABILITY OF FORMALIZED PRODUCTS OF POLYVINYL ALCOHOL By Kenichi Tanabe and Osamu Morimoto (I) FORMALIZED PRODUCTS FROM AQUEOUS SOLUTION OF POLYVINYL ALCOHOL AND FROM UNHEAT-TREATED POLYVINYL ALCOHOL FIBER Dye-absorptions with a direct color (C. I. No. 325) are determined for formalized powders obtained by formalizing polyvinyl alcohol in aqueous solution and for formalized fibers obtained by formalization of unbeat-treated polyvinyl alcohol fiber. For the powders the relation between dye-absorption and degree of formalization is expressed by a single curve, which begins to decline rapidly at about 80 mole % of degree of formalization, and tends to become almost an undyeable state at about 90 mole %, without dependence on conditions of reaction. For fibers these degrees of formalization are shifted to lower degree of formalization by 10-20 mole % than those of powders respectively. When the powders and the fibers are swollen by dipping in aqueous phenol solution, it is indicated that accessible hydroxyl groups of the latter are increased clearly by the treatment, but for the former no appreciable change in them is recognized. These results suggest that the formalized powders have fairly homogeneous distribution of formal groups and almost all remaining hydroxyl groups are accessible, whereas the fibers are more hetero -geneously substituted , some of the remaining hydroxyl groups are in-accessible, and by swelling a part of them becomes accessible. (II) FORMALIZED PRODUCTS FROM HEAT-TREATED POLYVINYL ALCOHOL FIBER. Heat-treated polyvinyl alcohol fiber is formalized under various conditions of reaction and the properties particularly dyeabilities with direct colors of the obtained fiber are examined. As formalization proceeds the dye-absorption is generally found to increase initially and then decrease through a maximum. The better dyeability at the same degree of formalization and the higher degree of formalization at maximum dye-absorption are obtained, the more swellable to fiber the condition of reaction. These results suggest that the effect of increasing dye-accessible regions due to swelling overcomes that of blocking hydroxyl groups due to formalization in the range of low substitution, whereas the effect of the latter prevails as substitution further proceeds. It is shown that dyeability of Vinylon is improved up to extent comparable with that of cotton or viscose rayon by employing more swellable conditions of formalization than usual. (Received 17. 7. 1954)