Polysiloxanes

Polysiloxanes were developed in the early 1990′s and are one or two part organosilicon polymers with high flexibility, low glass transition temperature, and low surface energy [1, 2]. Polysiloxanes are favorable for use in protective coatings due to the lack of isocyanates, good adhesion, and rapid curing properties [3]. Laboratory testing has shown good gloss retention, color stability, wear resistance, and excellent corrosion prevention performance, leading the US Navy to adopt the chemistry as a replacement for its traditional silicone alkyd topcoat system used on ships’ freeboard and topside areas. The coating’s properties ensure that surfaces can be easily cleaned and maintained, providing a longer service life than the silicone alkyd, especially when coupled with NAVSEA-approved cleaning kits [4].

Polysiloxane coatings are qualified to MIL-PRF-24635, Coating Systems, Weather-Resistant, Exterior Use, typically as high-durability coatings (Types V and VI) that can contain additional pigments to reduce heat absorption by the substrate (low solar absorbent – Class B) and diminish the appearance of rust staining.

Polysiloxane coatings are typically applied with conventional airless spray equipment or by brush or roller. Brush or roller application is normally used for touch up of small areas. Conventional airless spray systems are typically used for the coating of large surface areas.

References

1. Jones, Richard, G. Silicon-Containing Polymers. The Royal Society of Chemistry; Cambridge 1995.
2. Zeigler, John M. and Fearon, F. W. Gordon. Silicon-Based Polymer Science. The American Chemical Society; Washington DC 1990.
3. Wilson, Lee, Field Performance of Polysiloxanes, JPCL, March 2012, http://www.paintsquare.com/archive/?fuseaction=view&articleid=4637.
4. SURFMEPP Public Affairs, Cleaning Kits Provide New Canvas for NAVSEA Maintenance Strategy, April 21, 2017, http://www.navsea.navy.mil/Media/News/Article/1159116/cleaning-kits-provide-new-canvas-for-navsea-maintenance-strategy/.