Some slivers or rovings held between top and bottom aprons show a kind of wave motion by the schuffling action produced by irregular travelling speed of each apron band on the main draft field of the long draft spinning frame. The larger their maximum variation of travelling speed, and the smaller inter-fiber friction in slivers, the more frequently is such phenomenon. Such wave motion in slivers introduces a variation of the drafting curve on its back half.
After theoretical studies on the location of floating fibers in the drafting zone, it has been shown that the fiber end density function n0(x) of floating fibers and h0(x) or g0(x) of the fibers gripped by back or front rollers can be reduced to formulas (2.6) (2.8) and (2.12) on the stational case, which are the solutions of differential equations (2.1) (2.8) and (2.10) respectively. To consider how the speed of floating fibers changes, this theory was applied to a cotton slubbing frame as an example. Comparing the theoretical values of n0(x) with observations, as shown in Fig. 7 and 8, it may be found that the speed change points of floating fibers distribute between x=15/8 and 2 inches (where x is interval betwecn fiber front end and back nip point) for viscose rayon staple, and between x=7/8 inches and front nip point for cotton fibers.
The variation of loop inclination, the number of wales and courses per inch, and loop irregularities of silk and rayon fabrics were abserved under varying knitting conditions, viz. twists of yarns, moisture contents in yarn, rate of yarn feed and yarn tension during knitting. As the twist increases, the degrees of loop inclination, courses per inch and loop irregularities are increased. The appearance of the silk fabrics is not much influenced by the amount of water contained, but in the case of rayon fabrics irregularities of the loop are increased when the regain is too high or too low. The higher the yarn tension and faster the yarn feed, the greater the loop irregularities of the resulting fabrics.
We made the wheat starched yarn bundles of the filaments of different denier, and examined the various physical properties. (1) Applying Euler's formula concerning the buckling of long pillar to calculate the flexual rigidity and Young's modulus, they were found increased in proportion to the number of filaments. (2) Golden & Rankine's formula were applied to obtain more detailed properties. (3) By means of cantilever, Young's modulus was again calculated. (4) Like in the previously reported, case the constricting elasticity was measured, and the similar tendeney was obtained. (5) We measured the quantity of starch of each sample, and found increased in proportion to the number of filaments. (6) In consideration of the above, we found that the effective degree in sizing increased as the number of filaments is increased.
Instead of using free formaldehyde solution, hexamethylenetetramine (CH2)6N4 was used as acidic solution for the formalization of silk fibroin. Experimental results obtained may be summarized as follows. (1) The best reaction conditions were found to treat silk fibroin in 0.5-1.0% solution of (CH2)6N4, to which 8 equivalents of acetic acid were added (bath ratio 1:50), warmed to 90°C and kept for 40-60 minutes, then rinsed well, centrifuged and dried. (2) CH2O combined with silk fibroin was found to be 0.7% and its alkali solubility was 0.40% which corresponds to 1/6 of that of untreated silk. (3) The tensile strength of the treated silk fibroin, especially its wet strength increased remarkably and the ratio of wet and dry strength reached 92.5%, which is the same value for synthetic fiber, Nylon. (4) Silk fibroin formalized by (CH2)6N4 showed absolute insolubility by Schweitzer's reagent. (5) Affinities of dyestuff and absorption of bromine decreased more than that formalized by free CH2O solution This formalization seems to take place not only in the formation of cross-linkages between serine residues but also between tyrosine residues. (6) The X-ray pattern of (CH2)6N4 treated silk fibroin coincides with that of untreated silk, so that it is true that in this case also formalization took place only in the amorphous region, crystalline region being left intact. (7) The basal costs of chemicals used in both cases of (CH2)6N4 and free CH2O solution were the same, so that the more effective process of hexamethylenetetramine may be applied advantageously in industrial scales.
We found that the use of non-ionogenic substances in both silk scouring and direct dyeing decreases the light fastness, but increases the brightness of the shade of dyed silk. The metallic salts contained in the water used for scouring and dyeing operations have the increasing effects of the light fastness.
Viscose rayon was dyed with various direct cotton dyes and the relation between stimulus values (S) and dyeing temperature was observed. Stimulus values were observed by means of the spectrophotometer. By this method direct cotton dyes were classified into various types, but the classification was more difficult than in the case of acetate dyes. In general, stimulus values (S) of the most of direct cotton dyes are not influenced by the dyeing temperature. So, adding to the previous report, we were preferred to dye the blended fabrics at high temperature (about 90°C) by the so-called “one bath method”.
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.
The softning points and solubility in aceton of cellulose acetate treated with phenyl-isocyanate and p. p-diisocyanate-diphenylmethane were measured, and their behaviors were compared and discussed. The softning points rose with increase of nitrogen contents in the sample treated with diisocyanate, but fell in that treated with monocyanate. The solubility in acetone decreased sharply at about 0.5% nitrogen content in the sample treated with diisocyante, but no change was seen in that treated with monocyanate.