AVCO-DISPERSANT NS

DISPERSING AGENT FOR DISPERSE AND VAT DYES
AVCO-DISPERESANT NS is a non-foaming dispersing agent used in dyeing of Polyester, Polyester blends and Acetates with disperse dyestuffs.AVCO-DISPERESANT NS is used also as a dispersing agent in dyeing processes with vat dyestuff, and for stripping-off cationic dyes and fixing agents.

SPECIFICATION:

Appearance Sulphonated condensed polymer in aqueous solution.
Chemical nature Brown liquid.
Foaming Non-foaming at all.
Ionicity Anionic.
Solubility Dilutable with cold and warm water in any ratio.
Specific gravity at 20°C 1.12 – 1.16 g/cm3
Stability to: Acids, Alkaliks & water hardness } Good under the conditions normally found in commercial practice
Storage stability Good for at least 12 months.

APPLICATION:

  1. Dyeing with disperse dyes
    In normal cases 1 g/l AVCO-DISPERSANT NS suffices, in difficult cases up to 3 g/l AVCO-DISPERSANT NS are used.
    A particular advantage is that excess concentrations of AVCO-DISPERSANT NS have no adverse affect.
    Following is an example of a procedure for HT dyeing:
    • Warm bath to 50-60° and add 1-3 gr/l AVCO DISPERSANT NS.
    • Adgust pH to 4-5 with acetic acid or with AVCOCID ACD (acid buffer).
    • If necessery add 1-2 g/l AVCONAL PLD (levelling agent).
    • Add the dispers dyestuff (pre-dispersed in water and filtered).
    • Raise the temperature to 125 – 135°c and dye for 30-45 minutes.
    • Cool down slowly to 80°c and drop bath.
    AVCO-DISPERSANT NS is not recommended for use with optical brighteners. For this purpose use AVCONAL BM.
  2. Dyeing with vat dyes
    The presence of AVCO-DISPERSANT NS as a protective colloid and dispersing agent is particularly beneficial in dyeing with vat dyes where high concentrations of dye or highly concentrated powder or paste grades are being used. Because of its stabilizing action AVCO-DISPERSANT NS is also very useful in stock vats with limited stability and in special dyeing processes such as the gradual temperature rise process and in dyeing with disperse and vat mixture dyes. An addition of 10 g/l AVCO-DISPERSANT NS to un-vatted dye dispersion prior to the addition of Caustic Soda and Hydrosulfite will greatly improve the stability of stock vats.

    It is advisable to add a further 1 g/l AVCO-DISPERSANT NS to the dye-bath so as to utilize fully the dispersing action of the product. Excellent dye-bath stability in circulating liquor machine dyeing is achieved with 3 g/l AVCO-DISPERSANT NS. For the shock oxidation of vat dyes 2-3 g/l AVCO-DISPERSANT NS are added to the oxidation bath. This prevents any oxidized vat dye still left in the bath from filtering out and impairing the rub fastness of the dyed material.

  3. After treatment in the dyeing of Disperse/Reactive and Disperse/Vat.

    Disperse dyes stain cellulosic fibres in the following processes:

    • 1.During dyeing
    • 2.Due to thermomigration effect which occurs during the soaping-off process.
    • 3.In the reverse method -preliminary dyeing of cotton followed by dyeing of polyester(noreduction clearing is possible).
    Removal of the unfixed disperse dye is obtained by final treatment of the goods at 80°C with 1-2 g/l AVCO-DISPERSANT NS for 15 min.
    For dark shades repeat this process. This treatment ensures high wash fastness to the goods.
  4. Stripping-off cationic fixing agents
    Use the following recipe:
    Formic acid 2 – 4 cc/l
    AVCO-DISPERSANT NS2 – 4 g/l
    Treat at 90-90°C for 30-45 min. and rinse.