15.4 Novel CNSL-Based Waterborne Zn-rich Primer Systems for Protective Coatings
(Room 237-239)
11 Apr 18
11:30 AM
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12:00 PM
Tracks:
Session 15: Bio-Based Coatings, Session 15: Experimental Designs & Concepts
Low VOC waterborne (WB) Zn-rich primers and high performance WB epoxy primers have been developed based on novel Cashew NutShell Liquid (CNSL)- derived curing agents for industrial and protective coating applications. Those unique WB curing agents were synthesized from a natural, non-food chain and renewable biomaterial and could help to formulate WB primer systems that meet strict VOC regulations as well as high performance requirements.
This paper will present the latest performance studies of new CNSL-based WB Zn-rich primers and epoxy primers, and discuss some of the challenges faced in formulating such systems.
The new 2K WB Zn-rich primers were formulated with a water-free CNSL-based curing agent. Study results showed the WB Zn-rich primers had good compatibility with various commercial solid epoxy dispersions and delivered good cure and mechanical properties; importantly, those WB Zn-rich primers provided superb adhesion to both metal substrates and commercial polyurethane (PU) topcoats without the use of adhesion promoters. Excellent corrosion protection and good resistance to undercutting at the scribe were observed after 3000 hours Q-Fog exposure.
Additionally, newly developed WB high performance primers based on zero-VOC WB phenalkamines were evaluated either in combination with WB Zn-rich primers or by direct application to metal substrates. It has been found that those WB epoxy primers could enhance corrosion protection as mid-coats to WB Zn-rich primers; and when used as direct-to-metal coatings, WB epoxy primers also exhibited good mechanical and adhesion properties that benefited the overall anti-corrosion performances.