Tuesday, May 23, 2006

US Patent 7048771 - Nanoparticle Textile Dye


Using nanoparticles as dyes and inks goes back several years. In fact one of the first patents claiming an application of fullerene nanoparticles was for an ink composition (see US Patent 5114477).

US Patent 7048771 alleges that the use of carbon black nanoparticles in polymeric textiles is new. Specifically it claims

1. A nanoparticle processed textile and polymer system, said nanoparticle processed textile and polymer system comprising: a textile material having an embedded nanoparticle by diffusion, wherein said embedded nanoparticle is distributed in a gradually diluted pattern, having a higher density at or near the surface of said textile and polymer system and gradually decreasing density toward the core; and wherein said nanoparticle is carbon-black.

An interesting earlier patent (not cited in the '771 patent) is US 5900029


This patent also teaches carbon black dye for polymeric textiles and claims

1. A process for coloring a fiber or textile, comprising treating the fiber or textile with a modified carbon black having at least one organic group attached to the carbon black.

It is noted that the '029 patent doesn't refer to carbon black as "nanoparticles" but carbon black typically has diameters on the order of tens of nanometers (see for example "Carbon Nanotubes and Related Structures" by Peter Harris, pgs. 246-250.)

This situation demonstrates how changing terminologies can greatly effect a patent search. A review of the search logic used by the Patent Examiner responsible for US 7048771 reveals that terms such as "nanometer"or "nm" or "nanoparticle" were used to limit the search. This may not be surprising due to the emphasis of "nano" in the claims of the '771 patent, however the cost of such shifts in terminology is a failure to identify important prior art such as the '029 patent.