The dyeing behaviour of a number of dye mixtures on three types of fibre has been studied by the method based on assessment of colour build up under practical dyeing conditions, as well as under ideal conditions. Some a*b* and L*C*ab diagrams are constructed for both the conditions. These diagrams give valuable information about the dyeing behaviour of the dye mixtures. The technique reported in this paper will prove useful to a practical dyer for determining the compatibility of dyes in mixtures.

The load-elongation values of individual filaments in a multifilament yarn were studied. The behavior of individual filaments in a bundle is not the same as that of filaments tested individually; therefore, the load-elongation diagram of a multifilament yarn has to be used to arrive at tenacity values of individual filaments in a yam. A technique for obtaining load-elongation values of individual filaments was developed using the breaking steps in a load-elongation diagram of a multifilament yam. Preliminary results are described.

This paper describes the technique of finding the distribution of load-at-break and elongation-to-break of filaments in a multifilament yarn from the breaking steps in a load-elongation diagram. There is a correlation between the distribution data and the performance of undrawn nylon 6 yarn on the draw-twisting machine. The distribution in the drawn yarn is correlated with that of the undrawn yarn. The effect of spinning speed of the filament yarn on the distribution is brought out using lowspeed spun nylon 6 yarn and MOY and POY polyester. The effect of the hot water relaxation process and aqueous dyeing process on the distribution is also studied.The behavior of individual filaments in a bundle is not the same as that of the filaments tested individually. Therefore, in an earlier paper [2], we used the load elongation diagram of a multifilament yarn to arrive at the mechanical properties of the individual filaments in the yam. We developed a technique which gives these properties from breaking steps in a load-elongation diagram of a multifilament yarn. In this technique, the tenacity value of a filament (TBALF) is obtained from the average load on the filament [2].In this paper, we have studied the effect of postspinning operations on the mechanical properties of multifilament nylon 6 and moderately and partially oriented polyester yarns by examining the distribution of tenacity (TBALF) and elongation-to-break as obtained by the technique mentioned above. The effect of the relaxation process on the distribution has also been studied by treating the drawn nylon 6 yarn with boiling water and under conditions of dyeing.Materials and Methods ' . The following yams produced commercially by J. K. Synthetics Ltd., India, were collected at various stages of their manufacture: (a) undrawn nylon 6 yarn (143 denier, 10 filaments), (b) undrawn nylon 6 yam (385 denier, 24 filaments) and its corresponding drawn yam ( 111 denier, 24 filament, zero twist), (c) moderately oriented (MOY) polyester yam ( 136 denier, 34 filaments) and the corresponding sequentially drawtextured yam (85 denier, 34 filaments), and (d) partially oriented (POY) polyester yarn (102 denier, 34 filaments) and the corresponding simultaneous drawtextured yam (85 denier, 34 filaments). Based on their performance on the draw-twisting machine, yams were classified as good, acceptable, and unworkable. The yarn was good when it stretched without any breakage in a draw-twisting machine. If the yam broke frequently it was rejected as unworkable. A yam with occasional breaks was acceptable.The relaxed samples were obtained as follows: (e) the drawn sample (b) was further treated with hot water (95°C, 4 seconds at 30 m/minute), and (f) the drawn sample (b) was dyed after winding on a collapsible spring with CI Acid Blue 113 (Erionyl Blue S5R) ( 1.S g/1, I:100::M:L ratio, at boil, 1 hour) in the conventional manner. · All the samples were conditioned (65% RH, 25°C) before we recorded their load-elongation diagrams on the Instron tensile tester (rate of elongation, 1...

Nylon 6 filaments containing 0–1.5% carbon‐black pigment are dyed to different depths of shade. The colour on the substrate is evaluated on CIELAB a* b* diagrams at given concentrations of carbon black and dye. The carbon‐black pigment acts essentially as a neutral dulling agent and only with a few dyes does it appear to alter the hue angle slightly. Thus, it is possible to use nylon 6 filaments containing carbon‐black pigment to produce dull shades by the overdyeing process. The dyed samples thus produced are exposed to mercury‐lamp light as well as daylight. The lightfastness is evaluated visually using the Blue Wool Scale. There is a remarkable improvement in the lightfastness of all dyes on nylon 6 containing carbon‐black pigment. The carbon black in the filament appears to protect both the dye and the polymer from the degrading action of actinic radiation. However, the remarkable improvement in the lightfastness is essentially due to the optical effect.