Wednesday, May 10, 2006

US Patent 7041372 - Bulletproof Nanotube Armor

Yet another patent that was pending for awhile. This patent was filed in September 2001 by Lockheed Martin and lays claim to entangled single wall nanotubes used in anti-ballistic material such as the armor of a tank, aircraft, or personel. Claim 1 reads

1. A structure arrangement for the protection of a host against an impacting ballistic element, the structure arrangement comprising: a substrate; the substrate coupled to the host; and a composite; the composite disposed on the substrate; the composite comprising a matrix; and a multiplicity of single walled carbon nanotubes; and the single walled carbon nanotubes arranged with respect to the matrix so as to define a substantially entangled array operable to engage the ballistic element.

The Examiner used a prior art reference dealing with a nanotube composite used for EM shielding (US 6265466). Unfortunately this was a very bad reference to use since the EM shielding of the '466 patent employed nanotube alignment for the shielding which contradicted the claimed feature of "a substantially entangled array" and the attorney successfully argued this point.

On first glance I'm a little skeptical of this patent since the advantageous mechanical properties of SWNT/polymer composites have been well documented since the late 1990's and one would think that it would have been obvious to a person of ordinary skill in armor manufacture given polymers such as Kevlar that were widely used for armor to employ SWNT for strengthening purposes. However, whether or not to provide "a substantially entangled array" may be a matter of experimental verification. In any case, if you want to bulletproof your car with entangled single walled nanotubes you better pay Lockheed Martin.