Improvement of Colour Uniformity During Dyeing Operation: The Case of Dress Gloving Leather
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Date
2018-06-17
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Addis Ababa University
Abstract
In leather industry, the tanner produces a production lot with large number of leather samples to
match a colour provided by a client. However, even when the leathers are dyed with the same
colorants under well monitored conditions may show some colour non-uniformity. This is highly
challenging today for leather manufacturers, especially glove producers to sort colour of leathers
consistently. The present study is focused on identifying the factors of colour variation during
dyeing operation and reducing colour non-uniformity by managing the factors with welldesigned
dyeing
recipe.
Dyeing properties of the dyestuffs was investigated, by choosing two commercially available dye
stuffs. Factors of colour non-uniformity are identified by conducting dye trials on possible causes
of colour non-uniformity with four different well-designed dyeing recipes. When concentration
of dyestuff, substance of skin or length of dyeing float are varied individually keeping others
factors the same, a perceivable total colour difference (∆E*≥0.5) is observed.
Controlling and monitoring of colour non-uniformity is analyzed by conducting dye trials using
four different well-designed dyeing recipes viz. reverse dyeing recipe, regular dyeing recipe, the
multiple stage dyeing recipe and regular dyeing recipe with dye levelling agent. The total colour
difference (∆E*) values obtained using multiple stage dyeing recipe was smallest as compared to
the other three recipes by varying all possible factors of colour non-uniformity individually.
From these observations, multiple stage dyeing recipe was the best alternative way to manage
colour non-uniformity.
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Keywords
Dyeing Operation, Dress Gloving Leather, Colour Uniformity