Ozone fading of acid dyes on nylon carpet yarn
Abstract
This study examined ozone fastness of 13 acid dyes on Du Pont nylon 6,6 yarns and five acid dyes on Allied Anso IV nylon 6 yarns. The nylon 6,6 yarns were tested in the non heat set, Suessen set and Superba set form. The nylon 6 yarns which were a fourth generation nylon treated with a stain resistant finish were also tested in the non heat set, Suessen set and Superba set form. The yarns were also analyzed for crystalline characteristics, amino end group content, washfastness, dye desorption behavior and dyebath exhaustion behavior. Data collected from all of the tests with the exception of the x-ray analysis were statistically analyzed with analysis of variance. The statistical analysis detected differences in the above mentioned tests as a result of differences in nylon type, heat treatment and ozone exposure. Dyed yarns were exposed to 2, 4 and 6 ozone cycles of fade in a gas exposure cabinet following procedures outlined in AATCC Test Method 129-1981. Test conditions within the exposure chamber were maintained at 85 $\pm$ 5% relative humidity, 0.3 ppm ozone and 104 $\pm$ 9$\sp\circ$ F. Color measurements using the CIE L* a* b* color measurement system monitored the changes in lightness and darkness and overall color change after each ozone exposure cycle. Ozone fastness testing showed that the dyed yarns became lighter and exhibited increasing amounts of color change as a result of ozone exposure. Nylon 6 yarns change exhibited significantly greater changes in lightness and darkness and overall color change than the nylon 6,6 yarns. Superba set yarns measured greater changes in lightness and darkness and overall color change than non heat set or Suessen set yarns, This pattern of results was observed repeatedly with the remaining tests in this study. Nylon 6 yarns also measured the greatest changes in lightness and color change as a result of washing, lost the largest percentage of dye during desorption and measured higher dyebath exhaustion than the nylon 6,6 yarns. These results and the results obtained by x-ray analysis suggested that the nylon 6 yarns had physically different amorphous regions than the nylon 6,6 yarns. Specifically the amorphous regions within the nylon 6 fiber were more open than the amorphous regions of the nylon 6,6 yarns. This condition facilitated dye mobility into and out of the fiber structure thus causing a higher degree of dyebath exhaustion and greater dye loss during ozone exposure, washing and desorption than with the nylon 6,6 yarns. Differences in physical structure of the amorphous regions also explain why the Superba set yarns measured the greatest color changes during ozone exposure and washing and why the yarns lost the most dye during desorption. The Superba setting process produced yarns with more open amorphous regions than the Suessen set yarns hence the Superba set yarns exhibited poorer ozone and washfastness.
Degree
Ph.D.
Advisors
Ladisch, Purdue University.
Subject Area
Textile research|Home economics
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