NEW FINISHING OPTIONS FOR DIFFERENTIAL DYEING OF COTTON GARMENTS
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ABSTRACT Fabrics which have been chemically modified so that they are partly cationic offer the garment dyer the potential for differential dyeing of cotton garments. Methods for producing differentially dyeable garments using finishing based on a crosslinking system and a catiorlic reactive additive have been reported. In this work, two additional variations for producing unique cationic fabrics have been explored. In one case, a double treatment with stones on a cotton garment will enable the dyer to achieve a two color effect on a white background. This is accomplished using a stone treatment with the crosslinker cationic system, followed by a second stone treatment with a resist containing a base and a reactive dye. Then, the finish is cured with the dye being fixed at the same time. After excess dye is washed off, the cationic areas of the fabric are dyed. The cationic areas of the fabric are dyed under acidic conditions with a second reactive dye. The other approach explored in this work is based upon a controlled modification of stone finishing with a cationic formulation on a cotton garment or fabric sensitized with a crosslinker and an acid catalyst. In this case, the concept of latent basicity leading to changes in pH during drying and curing is utilized to achieve a non-uniform cationic character of spots on fabrics treated with stones or other methods to produce a partly cationic fabric. This is accomplished with a cationic or cationic-amine formulation in which neutralization of a basic non-volatile amine component is done with a volatile weak acid such as acetic acid. When the fabric is dried and cured, the acetic acid evaporates and the spot touched by the cationic formulation takes on its own non-uniform character due to interaction of the latent base with the metal salt catalyst used in sensitizing the fabric. The usual effect in this case is that the edges of a spot have a much higher amount of grafted cationic than the interior of the spot. The unique character of these spots become apparent on dyeing of the fabric. Unusual effects can be achieved by using two color dye formulations or by double dyeing. This concept of latent basicity has been employed in spray treatments, printing and finishing on the curve blade applicator in addition to stone finishing. Examples of garments and fabrics produced by these methods will be shown. |
©National Cotton Council, Memphis TN |
Document last modified July 8, 2004
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