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Pad Dyeing
Pad dyeing is the method in which the fabric is run through the dye bath in open width and then between the squeeze rollers that force the dye in to the fabric.
Pad dyeing, like jig dyeing places tension on the fabric while it is passing through the pad, with a tendency towards flattering and loss of the full hand of a material. Most pad dyeing is done as part of a continuous dye system or continuous dye range. Where large quantities of fabric are continuously run through a pad, then in to a heat or steam chambers (to set the dye), then in to washers, rinsers and dryers and finally emerging as completely dyed fabrics.
Cold pad batch dyeing:
This technique is the variation of pad dyeing. It is used for wool piece-goods to overcome certain disadvantages of beck dyeing them in light bright shades. Wool fabric is immersed in the dye liquor at room temperature.
After the excess liquor is squeezed out by the pad rollers, the roll of fabric is wrapped to prevent drying. It is then rotated slowly for up to 48 hours to obtain uniformity of dye application. The fabric is then washed in a mild alkali solution to remove the liquor additives and unfixed dyes. Finally the cloth is extracted and dried.
A faster system may be used for cotton and cotton/polyester fabrics utilizing reactive dyes. The dyestuff and alkali are combined in one bath through which the fabric is passed. Excess liquor is squeezed out on the mangle and the fabric is batched on rolls which are then covered with plastic sheets to prevent evaporation. It is subsequently washed, preferably on a perforated beam wash for efficiency and reduction of water consumption.
Merits:
- This cold pad batch dyeing method uses less energy, less water, which results in less pollution.
- It has the desired stability and rapid fixation while providing reliable and consistent shade.
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