Three POY yarns of 80/100, 80/48, and 80/34 denier/filament are textured with four variables at five levels. The Box-Hunter statistical experimental design is used to produce thirty-six samples in each case. The effects of texturing variables—draw ratio, disc surface speed to yam speed ratio ( D/Y ratio), first heater temperature and heater contact time on tensile properties, crimp characteristics, dye uptake, broken filaments, and tight spots—are studied. First heater temperature and draw ratio have a significant influence oh tensile, crimp, and dyeing properties. With increased D/Y ratio, broken filaments decrease but tight spots increase. A proper selection of the D/Y ratio gives acceptable levels of broken filaments and tight spots.

Anionic modified and normal poly(ethylene terephthalate) yarns were heat set at temperatures from 100 to 220°C and times from 3.75 to 45 seconds. Tensile properties, critical dissolution times, and dye sorption of these yarns were examined as a function of time and temperature of heat stabilization. Melting behavior (DSC thermograms), thermal stress, and critical dissolution times vary as a function of time and temperature of heat setting in the same way for both cationic dyeable and normal PET yams.Anionic modified or cationic dyeable polyester is increasingly being used in synthetic textiles because of its capacity to absorb basic (cationic) dyes that can give deep, attractive shades. Quite often, textiles containing both anionic modified and normal polyester yams have heather-like effects because of their differential dyeing characteristics. Heat setting of these fabrics on stenters is one of the important steps in processing them to finished goods. While a large volume of published data [ 1,4,5 ] is available on the effect of time and temperature of stabilization on the important properties of normal poly ( ethylene terephthalate) (PET), little is readily available on cationic dyeable PET. When both polyesters are used together, the practical significance of comparative studies on the effect of time and temperature on their properties is particularly important.We have made comparison in this work, where both the anionic modified and normal polyester yams are heat set at temperatures ranging from 100 to 220°C and for durations from 3.75 to 45 seconds. These short durations are used because in an actual commercial process, fabrics are heat set on a stenter with dwell times ranging from 10 to 40 seconds. The setting is done under nominal tension so as not to allow any dimensional changes during heat treatment. ExperimentalDrawn 50 denier normal (unmodified) and anionic modified PET yams, from Nirlon Synthetics Fibres & Chemicals Ltd., Bombay, were heat set at 100, 120, 140, 160, 180, 200, and 220°C with the help of Dynafil-M, using a pre-tension of 0.15 CN/dtex. The length of the heating tube was 75 cm, and the yam speeds were kept at 12, 6, 4, 2, and 1 meters/minute during heat setting to obtain heating contact times of 3.75, 7.5, 11.25, 22.5, and 45 seconds, respectively, in each case, producing a total of 72 samples. During heat treatment, thermal stress (contraction force) was measured in terms of cN. The thermograms were obtained on a differential scanning calorimeter ( DSC ) using the following testing parameters: scanning range -5 mcal / second, chart speed -10 mm / min, heating rate -20°C/min, and weight of the sample -5 mg.Critical dissolution times were measured in terms of seconds for each sample using 100% phenol as solvent at 50°C. Tensile testings were done on an Instron ( model 6021 ) using a test length of 250 mm. All samples were dyed in the same dyeing conditions using Foron blue SE-2RI, and dye uptake was measured by the dissolution method (using phenol and tetrachloroethene as solvent) o...

We have studied the effect of texturing parameters such as draw ratio, ratio of disc surface speed to yarn surface speed (D/Y), first heater temperature, and heating contact time on various properties, including tensile strength, crimp characteristics, tight spots, and broken filaments. Dye uptake in terms of K/S and critical dissolution time are examined as a function of draw ratio and heater temperature. Cationic dyeable polyester (CDPET) is compared to normal polyester with respect to texturing behavior, and properties of the resultant yarns are reported.