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Abstract:
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Package dyeing frequently has the following two significant drawbacks: nonuniform
package densities that can lead to unlevel dyeing within yarn packages and an
additional processing step (backwinding) following dyeing. Packages with nonuniform
densities offer a quality challenge to the dyer since a primary goal of package
dyeing is to evenly penetrate all areas of the packages with dye liquor to ensure
levelness and repeatability. Backwinding offers a cost challenge to the package dyer
because it becomes an additional processing step whose costs either have to be
absorbed by the producer or passed on to the customer.
Limited research has been conducted regarding dyeing levelness and unwinding
performance involving changes in the construction of two-ply yarn packages at the
two-for-one twister, a process that typically requires random winding. Furthermore,
investigations into the effects of press packing at the kier and its effects upon dyeing
levelness and unwinding performance of two-ply packages are also limited.
For this research, two-ply polyester packages were dyed with liquor flow rate
and package construction variations to determine the effects upon dyeing levelness and
unwinding performance. Rieter-Scragg's PPA3 was used to evaluate unwinding
performance. Packages were also dyed under two levels of compression to determine
the effects upon dyeing levelness and unwinding performance.
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