Consumer-electronics-grade protective conformal coating for mitigating tin whisker risk on electronic components with pure-tin-plated surface finishes
15 August 09
(Rev. 2 changed mixing ratio)
Green-Guard is a clear (transparent green), low-modulus, two-component urethane coating system designed specifically for containing the tin whiskers that grow from pure-tin-plated finishes on ROHS-Compliant components on electronic circuit boards and their components. It has all the normal electrical insulating qualities of conventional printed circuit board conformal coatings. It is repairable.
When the liquid components of Green-Guard are combined, the mixture is a non-Newtonian fluid (meaning has a nonlinear flow/viscosity characteristic known as thixotropy), and is intended to drain to a wet-film thickness of about 2.5 mils. At 40% solids, it is intended to give a nominal dry-film thickness of about one mil on flat surfaces. Due to its nonlinear viscosity properties, it will give much better corner/edge coverage than materials not possessing thixotropy.
Application may be by dip, spray or brushing.
When cured, Green-Guard is specified to contain a three-micron diameter whisker at a 25-micron (one-mil) film thickness. The containment mechanism is that of Euler Buckling.
Green-Guard has excellent reversion resistance, and low outgassing.
Mil-spec approval is neither sought nor expected, as this material is intended only for consumer-grade products. It is not restricted for export, and is suitable for use on Consumer or some Industrial equipment.
Want to know more about
this new conformal