| 摘要 |
Certain reactive dyes have a commercial form in which they are not reactive with natural or synthetic polyamide fibres, and for a covalent bond to be formed with the fibre material must first be converted into a reactive state. The methods hitherto practised for this purpose were ultimately unsatisfactory since, depending on the conditions employed, either the amount of reactive dye made available was insufficient or, as a consequence of the vulnerability of the converted form to hydrolysis, a proportion of the dye is deactivated, which in both cases results in dyestuff losses. These defects are remedied by preceding the application process first with a treatment of such dyes under typical conditions, for example in an alkaline medium, to convert them into their fibre-reactive form and then to stabilise the converted form by changing the pH, for example to an acid medium. The dyes thus prepared are then used for the dyeing and printing of natural or synthetic polyamide fibres at neutral or acid pH. Such a measure provides the crucial precondition for acceptable yields compared to prior art procedures. |
