The effects of melt spinning conditions on the spinning aspects by a so-called candle spinning apparatus were investigated. At the excessively high spinning temperature, molten polyethylene are decomposed by heat or air resulting in the decrease of the maximum draft on the spinning process. The polyethylene samples having smaller _??_n show larger maximum draft on melt spinning. The maximum draft of a sample having the _??_n of 41×103 amounts to about one hundred at 180°C. The maximum draft becomes smaller as the linear velocity of the molten polymer extruded through the capillaries of the spinneret becomes larger. It is also discussed how the velocity of the molten polymer in the capillaries effect the expansion of the extruded molten polymer due to the relaxation of molecular chain orientation
The melt spinnings by the so-called candle melt spinning apparatus of several low pressure polyethylenes, _??_n of which range from 4×104 to 15×104, were carried out at about 250°C, and temperatures higher at than 300°C. The hot drawing of undrawn filaments was carried out at 80°C and 95°C in the hot water bath. Mechanical properties, crystallinity of undrawn filaments are as follows. The characteristic values of the small deformation of filaments such as stress at yield point are scarecely dependent on the _??_n of the sample, while those of the large deformation of filaments such as constant stress range, tensile strength and elongation are largely dependent on the _??_n of the sample. The stressstrain curves of filaments having, larger _??_n obtained by the spinning at higher temperature than 300°C resemble to those of the filaments having smaller _??_n and spun at lower temperature. The densities of filament range from 0.928 to 0.944, varying with _??_n and drawing conditions and are largely effected by quenching at the spinning process. The maximum draw ratio at hot drawing is larger with smaller _??_n and the better results are obtained by drawing at 95°C than 80°C. Some properties of drawn filaments are as follows. The tensile strength and the initial elasticity increases and the elongation decreases with increas draw ratio. The tensile strength at 30% elongation obtained by the interpolations are remarkably affected by _??_n and generally higher than 4g/d, and as a rule at smaller elongation the tensile strength exceeds over 5_??_6g/d. The effect of _??_n on the initial elasticity is not large. Several percent increase of tensile strength and decrease of elongation are obtained by the heat treatment. The densities of drawn filaments increase by drawing and heat treatment.
Cellulose xanthate strips, gelatinized to various degrees in NH4Cl bath (first bath) by varying the time running from nozzle to first roller, were regenerated successively under stretching in H2SO4 bath (second bath). Fine structures of regenerated cellulose filaments thus obtained were examined and the following results were obtained. (1) When gelatination takes place freely under the condition in which a gelatinizing strip slacks in NH4Cl bath, the effects of stretching in H2SO4 bath show more remarkably in decomposition of a xanthate filament in which there is yet no mechanical cohesion of all chains than in that of a cohesive xanthate. (2) When gelatination takes place under stretching, the extending effect of stretching in NH4Cl bath show more clearly at the stage in which a cohesive xanthate filament is formed by either prolonging the running time in the salt bath or by increasing the concentration of the salt, but the-effects of stretching in H2SO4 bath are small as described in the preceding section. (3) As a rule, the effects of stretching are shown more markedly in the gelatinizing process than in the regenerating process of gelatinized xanthate.
In the previous paper, the effects of fiber structure and the average degree of polymerization of cellulose chains on the shape of the fractional dissolution curve were studied. And it was found that the effect of the fiber structure on the shape of the curve is dominant. The swelling or solubility of the linear polymer is principally the function of both the length of molecules and the state of cohesion of the molecules. In this paper, the effects of the distribution of the cellulose chain length on the shape of the curve have been studied to confirm the results obtained in the previous paper. And the distributions of cellulose chain length of original pulps and the degree of polymerization of each fractional dissolved were determined. The results obtained showed the fractional dissolution curve does not represent the distribution of cellulose chain length of the pulp, and supported the results obtained in the previous paper. Furthermore, the results obtained in this paper and previous paper are discussed based on the fiber structure model.
The effect of moisture upon the rigidity of raw silk, viscose rayon and vinylon was examined, and the following results were obtained. 1) The rigidity of raw silk was gradually lowered according to the increase of relative humidity until the relative humidity reached about 65% RH, but above 70% RH it sharply lowered. On the relation between the rigidity and the moisture regain, following results were obtained. The rigidity of raw silk was slowly lowered according to the increase of moisture regain from 6% to 10%, and above 11% of moisture regain the rigidity was sharply lowerd, but after that it was gradually lowered again. Vinylon showed the similar behaviour to raw silk. In the case of viscose rayon, however, the rigidity was almost linearly lowered according to the increase of moisture regain from 7% to 26%. 2) The relative rigidity of wet raw silk to dry raw silk was about 0. 2, and that of vinylon was about 0.45. 3) The rigidity of the raw silk from the outer layer of cocoon was more influenced by relative humidity than that from the inner layer.
The fabrics composed of different twist yarns in the warp and filling, curl so much that they roll up diagonally into a double scroll. In this paper, these phenomena are analysed quantitatively by assuming the multi-filar suspension model. The test piese, 1×10 cm size, is cut from warp or filling way. When the twist (curl) angle of a lower end of specimen clamped at an upper end and loaded at the free end is measured experimentaly, the twist moment or twist force is theoretically calculated by the following similutaneous equations. where, W: load applied at a lower end of specimen. n: yarn density, θ: curl angle of a lower end, 2a: width of test specimen, l: length of test specimen, F: coupling force of a composed yarn, and subscripts W, F denote warp and filling ways respectively.
Crabbing, well known wool setting process, often causes undesirable effects on wool fabric finishing. In order to improve these undesirable effects in setting process, we studied the application of “Cold Set” in which mercapto acid is used, To estimate the total sulfhydryl content and the adsorbency of the mercapto acid on reduced wool, suitable conditions for the phospho-18-tungstic acid method or modified method described with zahn. Results obtained are as follows.: 1) Generally, under the severe conditioning and hydrolysis on reduced wool, detected values of -SH decrease. However, -SH detections in highly reduced wool which is heated at low temperature increase. 2. For reduced wool, the moderate hydrolysis conditions are preferable where as for untreated wool -SH and -S-S- determination method are used. Factors for moderate condition are 20% HCl, 105°C and 3 hr. 3) When untreated wool is hydrolysed in presence of free mercapto acid. A definite amount of mercapto acid disappeared.
Absorption isotherm curve of pure halogenic acids on wool has been obtained by electro-conductivity method. The values of 0.85 and 0.88 equivalents of HCl and HI per kilogram of wool have respectively been determined by inspection of the curve and by appling the Donnan theory of menbrane equilibrium the value obtained for the pH at 0.85/2 and 0.88/2 equivalents absorbed by wool are 2.3 and 2.5 Donnan theory supports that none of the halogen ions are combined with wool, but it was found from the above that I- has an affinity of wool as compared with the Cl-. Therefore the complete treatment of Donnan theory, considering anion affinity, leads to the following expression: instead of where a is the total hydrogen ions taken up by the fiber, V, the volume of internel solution, and f, the corrective coefficient (0-1) of anion affinity.
The change of the hue by dyeing concentrations and the relation between the luminosity and the purity were studied through the chromatical diagrams (see diagrams a, b) on dyeing of cellulose acetate. It was shown through the measurement of the colour by means of the automatic colour difference meter that the purity of the colour increases first with the increased concentrations and then it decreases to darker shades after it reached the maximum, the most brilliant point. Most of dyes give the maximum purity at 1_??_2% dyeing concentration and some of them at the deep shade. The relation curves between the luminosity and the purity make a comparison of the brilliancy possible to the dyes with the same colours by criticizing their own positions in the graph. For the most of dyes, the rate of decrease in luminosity falls with increased concentration while the concentration does not reach over a certain range, and the hue tends to change in shade toward the left or right turn in the chromatical diagram as the concentration is increased.
The relation between the dye concentration and its luminosity to the fibre was chromatically studied and it was found that there exists the following formula between them: logRd=klogc+logp or Rd=pck where, Rd: the luminosity of the dyed fabrics of acetate c: the concentration of the dye in the fibre k: the constant, named the luminosity gradient in dyeing p: the constant, named the standard luminosity in dyeing. It was also shown that it is possible to prescribe the chromatical characteristics of the dye in dyeing through p and k, and from this point of view the concrete connection between the colour and the dye concentration is emphasized.