纎維素系織物の樹脂加工に關する研究

第4報 Formaldehyde處理による纎維の染着性及び膨潤性の變化 第5報 Formaldehyde處理人絹糸及び單纎維の機械的性状

抄録

We studied the alterations of the dye-affinity and the swelling value of the cellulose fibre by formaldehyde treatment with hydrochloric acid catalyst.
Viscose filament yarns (300/50) were treated similarly as reported in part I, where yarns were immersed in the solution containing 12g HCHO and 0.1g HCI in 100cc and heated for 10 minutes at various temperature. Treated yarns were dyed before and after preparing of their cross-sections with Diamine Brilliant Blue G (C. I. No.511), then the dyed paterns on both cross-sections were compared. The cellulose fibre treated at 60°C. retards slightly the penetration of this direct dye molecule, but the inner portion of cross-section was dyed. However, the higher the heating temperature, the less the dye-penetration and dye-affinity of the inner section. Here, the temperature 80°C. is the point to be noted for above which the cellulose-formaldehyde reaction proceeds markedly. These facts were also ascertained from the swelling values of these fibres in water and 20% H₂SO₄.
We investigated further the alterations of the direct dye-affinities on the similarly treated spun rayon fabrics by the spectrophotometric analysis. The change of excitation purity and luminosity on the dyed treated fabrics with Nippon Scarlet B extra. (C. I. No.382) were found to coincide with the alterations on other vari _??_ us mechanical properties of the treated cellulose.
We studies the mechanical properties of viscose filament yarns (150/30) treated with formaldehyde in the presence of hydrochloric acid catalyst, and compared their values on fibers, yarns and fabrics. The procedures of every formaldehyde treatment were similar to those described in the previous report (IV).
Of the treated yarns, wet strength was commonly increased as compared with the untreated one, but the higher the treating temperature above 60°C., the less the increasing ratio. And dry strength was generally reduced, but to lesser extent than those of the spun rayon fabrics. In the case of fibre, both dry and wet strength increased with the rise of treating temperature.
There are slight differences in the shape and structure of composed fibers between filament yarns and spun rayon fabrics, but according to the results described in the above and previous report (I), it was indicated that the dry strength of the treated single fibre were increased, and that those on the yarns and fabrics were reduced, although the similar viscose rayon fibres were given the same formaldehyde treatment. This fact explaines that the predominant factors influencing on the mechanical properties of yarns and fabrics were those of each single fibre in the distributed form in their texture. The twist of the tested yarns was 102/m. In the spun rayon fabrics, each single fibre was to be twisted more. Therefore, in these cases, the torsional strength of single fibre predominated.
Then we must consider the knot strength, including the torsional strength. According to Table 2 and 3 above, those were all reduced by treatment with formaldehyde, and the higher the treating temperature, the less their strength.
The formaldehyde treatment hardend the viscose fiber, reduced the elongation, greatly increased the elastic recovery from a small elongation, and the yielding point on the stress-strain curve could not be recognized. These phenomena would be useful for increasing the crease-resistancy of their yarns and fabrics.