Description and salient Technical features
Lac dye is recovered from the lac processing waste water. This natural dye can be easily obtained in 100 tonnes or more quantities annually. Though there is a good demand for natural dyes now a days due to their eco-friendly nature, demand for this dye was poor as it could dye only wool and silk but not cotton and other cellulosics.
Therefore many processors were not recovering this dye. Technology developed consists of making cotton fabric and yarns dyeable with this dye by introducing amino groups onto them by pre¬treatment with either chitosan or a cationic dye fixing agent. Dyed material could be made colour fast to washing by treating it with dye fixing agent or eco-friendly mordants like alum or iron salts which provide different colours as well.
Dyed materials possess satisfactory to good colour fastness to washing, light, perspiration and rubbing.
No extra investment is needed as the process can be carried out in regular dyeing machines such as jigger, winch or a dye pot. Cost of dyeing a kilo of cotton material is about Rs.150 -170.
How the new technology will impact the income of the farmers / end users:
This technology will increase the income of lac processors directly and of lac farmers indirectly as lac dye recovered from process waters will further add to the income. Cottage and small scale dyers such as handloom weavers can get higher returns by using this dye as textiles dyed with natural dyes fetch higher value.
This technology is beneficial to environment in two ways. Firstly, recovery of dye from lac processing waste waters will reduce its colour and effluent load. Secondly it would partly replace difficult to biodegrade synthetic dye. It would be of special help to cottage and small scale dyeing units in meeting the effluent norms as they do not have access to effluent treatment plants