Utilization of cashew nut shell liquid for coating applications in local industries

Abstract

Cashew nut shell liquid (CNSL), which is locally obtainable in abundant quantity, has not been hither to commercially exploited in any Sri- Lankan industry. As the liquid has been identified as a mixture of phenolic substances with polymerizing character, attempts have been made in this work to investigate it's application in coating as a polymeric binder resin. In the procedure, raw -CNSL wa-; pur~fied by a modified technique and then treated with formalin( for polymerization. The polymerized product was then tested for its suitability as a polymeric binder resin in varnishes. The test results show that 1) the polymerized product could alone be used successfully as a binder resin with driers for making air drying varnish and 2) the polymerized product in combination with Short Linseed oil alkyd resin in the ratio of about 5 to 1 by weight could form an ideal binder resin forproducing stoving varnish.