By: H.D.Joshi, D.H. Joshi, M.G. Patel and S.R. Naik
Introduction
The production of multi-colour effects has been done by thehelp of differential-dyeingsystems. The term "differential-dyeing" is applied to fibres whichare of the same basic type, e.g., nylon but with different dyeing properties.To vary the dyeing properties of the fibre (nylon), chemical modifications areemployed.
In one case the substantivity of the fi
This can be done by using a stabilizer during polymerisationwhich has one or two carboxyl groups that can react with the amino end groupsof nylon polymer. The stabilizer also has one or two sulphonate groups whichmake the polymer anionic.
An example of such a stabilizer is di
HOOC-Nylon Polymer-NH2 + HOOC C6H3(S03Na)2 ------->
HOOC-Nylon Polymer-NHCQ-C6H3 {S03Na)2 + H20
(Cationic dye dyeable nylon)
Other alkali metal salts, e.g., lithium salt can also beused. 5-sodium sulphoisophthalicacid is also used to introduce sulphonate groups in nylon 6 polymer. TheintrOduction of the sulphonate group increases the affinity for basic dyes while the affinity for aciddyes is very low.
In another modification, the amine end
Aboutthe Authors:
The authorsare associated with Man-Made Textiles Research Association (MANTRA), Surat.
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