In the previous papers, the drawing mechanisms of amorphous PET fibres were discussed. In this paper, undrawn PET fibres are crystallized in water over the temperature range 80_??_100°C, and drawn in water at 70°C and 75°C. Then, the drawing mechanisms are discussed from the measurements of birefringence, density and orientation of crystallites. The results obtained are as follows: 1. The initial slope of birefringence-draw ratio curves and the maximum value of the birefringence increase with increasing crystallinity in the process of primary crystallization. 2. Though the crystallinity after completion of primary crystallization is about 20%, birefringence-draw ratio curves are no more affected by the change of crystallinity during the secondary crystallization, and it becomes independent of drawing temperature. Drawing behaviours of Nylon 6 are same as PET fibres crystallized to this degree. 3. In the hot drawing of samples crystallized to the middle process of primary crystallization in water above 90°C, an irregular structure appears under a polarizing microscope. 4. The birefringence-draw ratio curves for samples crystallized to completion of primary crystallization may be represented by following equations; where v1 and Δn1 are respectively the volume fraction and birefringence of the part which is deformed in accordance with Kratky's “first borderline case;” v2 and Δn2 are respectively the volume fraction and birefringence of the part which is deformed in accordance with Kuhn and Grün's theory for rubber photo-elasticity; α the draw ratio; <cos2θ> the mean square of direction cosine of orientation units for fibre axis; Δn0 and A the constant. 5. It may be considered that vl and v2 are 0.2_??_0.3 and 0.7_??_0.8 respectively until draw ratio 3.6; but v1 increases gradually with increasing draw ratio above 3.6 and becomes one at draw ratio 5.5 and Kuhn and Grün's theory can not be applied for this process. 6. It may be considered that the part deformed in accordance with Kratky's theory is composed of crystallites, and the other part deformed with Kuhn and Grün's theory is composed of amorphous molecular chains and a part of crystallites unfolded by drawing.
The effects of the fine structure of cellulose were studied on the grafting reactivity. As the factors of the fine sturcture of cellulose, the crystallinity and the ratio of diffraction intensity, (10_??_)+(002)/(101), were selected. The grafting yield was found to decrease as the crystallinity and (10_??_)+(002)/(101) increased. On the basis of the results obtained here, the grafting polymer is presumed to be formed mainly at the amorphous region of cellulose and the space between the micelles oriented to the direction of (101) planes. In addition, the effects of the above factors were studied on the moisture regain. Since the behavior between the grafting reactivity and the moisture regain in relation to (10_??_)+(002)/(101) was given the opposite result, the grafting reactivity is presumed to be affected by the physical factor such as the space between the micelles, in addition to the chemical factor such as the reactivity of hydroxy group, and the grafting polymer is presumed to be formed easily at the larger space between the micelles. Further, in the case of film having the constant crystallinity and (10_??_)+(002)/(101), the relation between the film thickness and the grafting reactivity was studied. The grafting yield was found to change by the film thickness and to reach the maximum yield at 400μ. From the result that the grafting yield was decreased as the film thickness increased at above 400μ, the grafting polymer is presumed to be formed easily at the surface layer of the film and not distributed uniformly through the whole layer of the film, and also the grafting reactivity is presumed to be disturbed by the oxidation of cellulose with CeIV, in review of the grafting behavior at below 400μ.
As the needle has barbs which entangle fibers in a web, the punched fabric is made by punching the random web. Compared with non-woven fabric, it has some defects such as shedding of fiber and punched holes. The needle punching machine was designed under the following considerations: As the web must not be moved during punching, the timing of feed and punch actions is important. Punch holes need to be distributed evenly and each second rank needle is better to be set at the center of the interval to the neighbouring first rank needles, and the third needle at the center of the interval between the first and the second ranks and so on. The needle is to be selected by the kind and fineness of fibers, the thickness and density of the web, etc.
When the web is punched by the needles with barbs, it is bored with holes corresponding to fineness of needles. The web is lifted by the lifting needles and pulled by the delivery roller. So the web is enlarged by puching. The thickness of fabric decreases on account of the enlarged area and condensation. Assuming that the specific density of fabric is ρ and the density of fibers is ρf, the relativedensity of the fabric, S is ρ/ρf. Anisotropy of tensile properties is due to the property of random web, if punching is uniform. If the entangle of fiber increases and the fiber does not move with increasing punches, the fibers will be broken. As the entangle is increased and at the same time fibers broken, the maximum breaking strength. will be observed within a certain range. The number of punches yielding the maximum strength increases with fineness of fibers. The punched fabric is mainly broken by the drawing out of fibers.
Recently a new method was found by authors in silicone water-repellent finishing of cotton fabric. This procedure consists of treating cotton with methyl hydrogen polysiloxane-cetyl dimethyl benzyl ammonium chloride-zinc acetate emulsion, and gives a high water repellency after repeated launderings by only air-drying at room temperature for 1 to 2 days. In this study the physical properties of cotton fabrics treated with this emulsion (I) were investigated and compared with those of the following fabrics treated in various silicone baths. II. methyl hydrogen polysiloxane emulsion (with no zinc acetate in I. emulsion) III. II. plus dimethylolethylenurea resin (two step process) IV. II. plus melamine-formaldehyde resin (two step process) V. Repelotex VI. V. plus melamine-formaldehyde resin (one step process) VII. V. plus urea-formaldehyde resin (two step process) VIII. V. plus urea-formaldehyde resin (one step process) IX. methyl hydrogen polysiloxane (n-hexane solution) The following results were obtaind: 1. Shrinkage values of untreated fabric are 2_??_4% in the case of no heating and 0.8% for heating at 150°C. Shrinkage of I._??_IX. are approximately 0% in the case of air-drying at room temperature after silicone treatment and also heating at 150°C. 2. Crease recovery of I, III. and IV. are 150_??_200%, and of II. is nearly 100% in comparison with that of untreated fabric on the occasion of air-drying. As for heating at 150°C that of I, III, IV, VI, VII, VIII. and IX are 120_??_160%, and II. and V. almost 100% as compared with that of the untreated. 3. Flex abrasion of I. and II. are 200_??_300% III. about 25% and IV. almost 80% as compared with that of the untreated babric on airdrying. With heating at 150°C II, VI. and IX. are about 400%, I, V. and VIII. approximately 200%, IV. and VII. 115_??_135%, and III, is 50% in comparison with that of the untreated. 4. Tear strengths of I. and II. are 110_??_120%, and III. and IV. about 70% in comparison with that of the untreated fabric in the case of air-drying. On heating at 150°C, III. and IV. are 60_??_70%, VI, VII, and VIII, about 80%, and I, II, V and IX. nearly 100% as compared with that of untreated. 5. Tensile strengths of I, _??_IV. are 50_??_70% in comparison with that of untreated fabric in the case of air-_??_drying. As for heating at 150°C, I, _??_IV. and VI, _??_IX, were 60_??_80% and V. is approximately 100% as compared with that of the untreated.
Various methods were used in treating a worsted fabric and a yarn with urethane prepolymer (adduct) synthesized from polypropylene glycol (P. P. G.) and a little excess of tolylene diisocyanate. Procedure I. Two-stage-treatment by using hexamethyl ene-diamine (H. M. D. A.) and adduct in CCl4 Procedure II. The same as Procedure I, except that water was used instead of H. M. D. A. Procedure III. First impregnated with ice cooled organic solution containing H. M. D. A. and adduct, and then open cured. Procedure IV. First impregnated with CCl4 solution of adduct, and then open cured. Procedure V. The same as Procedure IV except that “closed cured in nitrogen” instead of being “open cured”. Among these, Procedure I, is the most commendable technique for obtaining unshrinkability of wool. The effects of P. P. G. average molecular weights---400, 1000 and 2000---on polyurethane finished wool was investigated, and it was observed that with the increase of the molecular weight, the handle of the worsted fabric became softer and its shrink resistant property greater. After the treatment, crease recovery of worsted fabric remains is unchanged but its strength became greater. Yellowing caused by this polyurethane finish is small and it is not accelerated after the treatment.
In order to investigate the reactions in polyurethane finishes of wool, the treated wool was extracted with CCl4 and the Infrared spectrum of the extract was observed. In Procedure I., urea crosslinkages were synthesized by reacting terminal isocyanate groups of adduct with active hydrogens of H. M. D. A. at a phase boundary, then unreacted isocyanate groups of adduct, which did not exist at the phase boundary, reacted with urea groups to form biuret branch point. In Procedure II., formation of biuret crosslinking was shown, but unreacted isocyanate remained. In Procedure III., when the molar ratio of the reagent was;- Infrared spectrum of the extract showed a weak band at 1650cm-1 of urea, but when M=1/4, in addition to this band, a weak band at 1715cm-1 (biuret) and a strong band at 2270cm-1 (isocyanate) were observed. In Procedure IV., urea and biuret formation was shown. In Procedure V., the extract was practically the same as the original adduct. But when compared with the wool which was treated with the same method after it had been acetylated, it was found that the extraction rate of various organic solvents decreased. This means that there is a probability of reaction between isocyanate groups of adduct and reactive hydrogen atoms of side of side chains of wool.