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Title of Technology 

Cashew nut shell liquid and derivatives(CNSL)

Executive Summary

Cashew Nut Shell Liquid (CNSL) is a versatile by-product of the cashew industry and is the pericarp fluid of the cashew nut. The nut has a shell of about 1/8-inch thickness inside which is a soft honey comb structure containing a dark reddish brown viscous liquid. It is often considered as the better and cheaper material for unsaturated phenols. The distillation of CNSL produces cardanol, which is considered a pure form. CNSL has innumerable applications in polymer based industries such as friction linings, paints and varnishes, laminating resins, rubber compounding resins, cashew cements, polyurethane based polymers, surfactants, epoxy resins, foundry chemicals and intermediates for chemical industry. It offers much scope and varied opportunities for the development of other tailor – made polymers. Process for Polyurethane polyols from Cardanol for rigid foams, coatings: The polyols are developed form Cardanol, a renewable resource obtained as by product of cashew processing industry. The polyols are slightly cheaper than petroleum based polyols. Rigid foams have better compression strength, water resistance and thermal stability. It can also be blended with petroleum polyols for cost reduction or improved properties.
Light colour Reactive diluents for epoxy resins from Cardanol: The reactive diluents are developed from Cardanol, a renewable resource obtained as by product of cashew processing industry. It can be blended with commercial epoxy resins to improve the flexibility, thermal and water resistance proprieties.

Potential Market

India is one of the largest producer of CNSL and is mostly exported with limited value addition. In recent years many new companies have started making value added product form this oil in India. Thus, the production potential for the product is very high. There is good scope for the export of CNSL to other countries as well as usage in India. The value added products developed from CNSL/cardanol are shown in figure 1 below.

Technology Readiness Level – 6