A Study of How CNSL Blends Affect Coating Properties Synthesis and Studies of Corrosion-Resistant,Low-Cost,Water-Based Coatings for Steel Surfaces

摘要

Water-based coatings have been in use for decades,as they eliminate or reduce the use of petroleum-based solvents,which increase levels of VOCs,toxic substances and energy consumption.The coatings industry is focusing on four major techniques in the area of eco-friendly technologies:water-soluble,powder,radiation-curable and high-solids coatings.1 In this regard,aqueous,cashew nut shell liquid(CNSL)-based coatings have received increased attention because of the availability of agro-based CNSL.The CNSL constituents have two reactive units:phenolic OH,which is the hydrophilic part of the molecules,and the long C-15 side chain having an average of two double bonds(i.e.,the hydrophobic part that contributes to crosslinking and gives gradual and satisfactory drying and baking properties).2 The long hydrocarbon chain imparts great flexibility to its aldehyde condensate in the various drying oils.CNSL exhibits the following unique properties:agro-based,excellent water resistance,corrosion resistance,satisfactory chemical resistance,better flexibility and drying than other oils,very cheap,sufficient reactive sites.