BigPatents India

The invention relates to recovery of pigments from wash water generated in the process of manufacturing 'machine-tinting-colorants'. Machine tinting colorants are used to tint white bases of the water-based paints at retail outlets. These are made by dispersing highly concentrated pigments in water with the help of various additives and resins. The process invented by me makes use of an ultra filtration or Nanofiltration unit, which concentrates the wash water to increase the percentage of pigments in the wash water making it suitable for reuse. The product can be made to have consistent pigment concentration at desired levels. The selection of membrane required is done based on the molecular weight of the pigment in question. To ensure other criteria such as quality of water in the wash water, bacterial contamination, mixing up of various streams of effluent are eliminated with following modifications of the process such as use of specified quality of water in washing, conttd11ed procedure for cleaning, controlled storage and monitoring.