Cleaner Technology Transfer to the Polish Textile ... - Miljøstyrelsen

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The large water consumption in the rinse step is primarily caused by the large
number of baths but also by the common use of overflow rinses. Before the temperature
is raised in the rinse, the dye-stuff producers recommend a neutralization
when dye-stuff types with a VS reactive group are used. This neutralization
has, however, in some dye-houses, become usual practice for all recipes.
After neutralization the rinse consists of a number of soaping sequences: hot
soaping, warm rinse and overflow rinse. Table 2 shows a typical use of two
soaping sequences. In the hot soaping – bath no. 10 and 13 in table 2 – »soaping«
additives are used, covering surface active agents (detergents), complexing
agents and dispersing agents.
The reason for the use of complexing agents is protection against hardness in
the water and/or the cotton together with a need for an additive to hold the dyestuff
hydrolysate dispersed in the water.
The process is finalized with neutralization and treatment with softening
agents, necessary for the following sewing process.
Materials & methods
Cotton in the experiments All analyzed qualities of cotton, also the qualities used in the experiments, have
a rather constant total calcium and magnesium content of about 1500 mg/kg.
Dye-stuffs The investigated dye-stuff in this project are shown in table 3. There are 17
monoreactive and 7 bireactive reactive dye-stuffs, of which 15 dye-stuffs hold
the VS reactive group.
Table 3.
Investigated dye-stuff types. Abbreviations explained in text earlier.
Dye-stuff no. Trade name Chromofore group Reactive group Fixation %
1-4 Remazol Azo VS 70-80
5-6 Remazol Azo VS/MCT 75-78
7-10 Remazol Anthrachinone, Phtalocyanine VS 55-70
11 Remazol Azo VS/VS 86
12-14 Cibacron Azo FT/VS 73-82
15 Cibacron Formazan/metal FT/VS 79
l6-l8 Cibacron Azo FT 50-60
l9 Cibacron Formazan/metal FT 53
20 Cibacron Diazo FT 64
2l Drimaren Azo TCP 64
22 Drimaren Azo MCT 56
23 Levafix Azo FCP 78
24 Levafix Anthrachinone MFP 65
Performed investigations Table 4 gives an overview of performed investigations. The dye-houses have
chosen the recipes, and thus the 24 reactive dye-stuffs in table 3, as »difficult«.
Because of the very accurate balance between the used dye-stuffs in light shades,
they can be hard to obtain, and for dark shades the fastness can be problematic.
Analyses Analyses were made according to national standards and include ash content,