Paint & Coatings Industry - January 2009 - (Page 22)

Synthesis of an Eco-friendly, General- Agro-Waste he cashew (Anacardium occidentale) tree is native to northeastern Brazil, where it is called by its Portuguese name Caju (the fruit) or Cajureiro (the tree). It is now widely grown in tropical climates for its cashew nuts and cashew apple. Originally spread from Brazil by the Portuguese, the tree can now be found in all regions with a sufficiently warm and humid climate. The true fruit of cashew is the nut, a kidney-shaped structure of approximately 2-3 cm in length, which is attached to the end of a fleshy bulb, generally called the cashew apple. The shell comprises some 50% of the weight of the raw nut, the kernel represents 25% and the remaining 25% consists of the natural cashew nut shell liquid (CNSL), a viscous, reddish brown liquid. CNSL has a variety of industrial uses, which were first developed in the 1930s.1-3 CNSL is fractioned in a process similar to the distillation of petroleum and has two primary end products: solids that are pulverized and used as friction particles for brake linings, and an amber-colored liquid that is aminated to create phenalkamine curing agents and resin modifiers. Phenalkamines are primarily used in epoxy coatings for the marine and flooring markets, as they have intense hydrophobic properties and are capable of remaining chemically active at low temperatures. CNSL exhibits some outstanding properties such as excellent corrosion and water resistance, satisfac- T tory chemical resistance, and better flexibility and drying than other oils. CNSL also suffers from some drawbacks like dark color, lack of hardness and lack of toughness. These drawbacks can be overcome by modification with different resins, i.e., epoxy, phenolic, alkyd etc., to give a better system at low cost.4 In the present study, the modification of CNSL is encouraging because of its compatibility with other film formers to yield a new binder that combines the advantageous qualities of both CNSL and the modifier. While the CNSL contributes to the coating flexibility, corrosion and water resistance, durability and gloss, the modifier (like epoxy resin) confers adhesion, toughness, improves film hardness and chemical resistance. This study was undertaken to explore both the technical and economic benefits of modifying CNSL with maleinized rice bran oil (RBO) fatty acid epoxy ester resin. Both RBO fatty acid5-15 and CNSL are byproducts of rice bran and cashew nut. Chemistry of CNSL-Modified Epoxy Ester Resin Crude cashew nut shell liquid represents one of the major and cheapest sources of naturally occurring phenol such as anacardic acid, cardols, cardanols, methylcardols and polymeric materials.16 The interesting chemical characteristics of cardols such as the presence of a double bond at the 8-position of the By Manu Gupta, Research Scholar; P.K. Kamani, Assistant Professor | Department of Oil and Paint Technology H.B.T.I., Kanpur, India; and Deepti Shikha, Lecturer, Chemistry Department | Brahmanand College, Kanpur, India 22 JANUARY 2009 | W W W . P C I M A G . C O M http://WWW.PCIMAG.COM

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Paint & Coatings Industry - January 2009 Contents Viewpoint Industry News Calendar of Events Company News Names in the News Synthesis of an Eco-Friendly, General-Purpose Binder Based on Agro-Waste Materials Supplier Showcases – Green Technology Federal R&D Tax Credit Program Helps Coatings Industry in Tight Economy New Generation of Silica-Encapsulated, Ultramarine Blue High-Performance Pigments Cleaning Up in the Coating Business Low-Odor, VOC-Free Renewable Coalescents for Latexes Used in Very Low-VOC Paints Materials Watch Products Classifieds Advertiser Index

Paint & Coatings Industry - January 2009

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