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Home > Nanotechnology Columns > Magda Carvalho PhD, JD > Nanotextiles: Obviousness Barrier to Patentability

Magda Carvalho
Patent Attorney
Patent Law at M. Carvalho

Nanofiber scientists that engage in continuing research based on published data must design around to distinguish their inventions over prior art references for future patent protection This is because under patent law the non-obviousness requirement mandates that one having ordinary skill in the art would not have thought of the invention.

November 6th, 2010

Nanotextiles: Obviousness Barrier to Patentability

Nanotextile is the science that creates fibers or webs with active nano-particles. Nanotextile is coming from the laboratory to the market as nano-claimed products have already emerged on the market. Nanotextiles have led to the development of nanofibers (size range 10-100nm diameter), nanocompositions, nanopolymers, nanofinishes and others. The result has been the development of fibers and fabrics/webs that perform a range of functions including antimicrobial, water repellent, fire-retardant, thermally insulating, odor-reduction, heat retention, distinct colorations, reduced fading. These attributes may be applied to the fabric or web after treatment with the nano-particles. Nanotextiles technology can be used either on natural or synthetic fibers to bring the best out of it. It adds value to the article. We experience the great impacts of nanotextiles on clothing, hats, gloves, interior and exterior upholstery, carpets, sails for boats, filters, medical textile and many others.

Patent: Non Obviousness Subject Matter.

One requirement to get patent protection is that the invention does not reveal that it is an obvious variant of an invention already disclosed. Section 103(a) of the Patent Act recites in part: "A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains."

The Supreme Court has articulated the factual inquiries for obviousness.(1) Recently, the Court reaffirmed this high hurdle to patentability.(2) Additionally, to establish a prima facie case of obviousness the Examiner will apply the following standards to an application: (a) the prior art reference(s) must teach or suggest all the claim limitations; (b) the combination of references must teach the predictable use of prior art elements according to their established functions; and (c) there must be a reasonable expectation of success in combining the teachings of the references.

Ex parte Bao Tran, Appeal No. 2009-015050 (BPAI 10/21/2010).

One of the most difficult areas for nanotech inventors is to overcome the non-obviousness barrier.(3) This patent application entitled "Nano-Particles on Fabric or Textile" illustrates such case. Here, the "building blocks" of the invention were already disclosed and patented by another. Besides, the inventor did not have the argument, to defeat the rejection based on non-obviousness, that the invention yields unexpected results not recognized before which would have rendered the invention non-obvious to an artisan.

The invention involves a method of processing fabric or textile that minimizes fading and shrinkage of fabric articles. The invention claims a wash durable article and method of making it. The substrate includes fibers, woven and nonwoven fabrics (natural or synthetic) as well as cellulose-based papers. The substrate is made up of strands of smaller fibers. A smaller fiber strand can be either porous or non-porous. The porous type has individual voids in which some are at partially filled with nano-particles. The nano-particles form projections on the outside of the smaller fibers and the single fiber. The available void spaces in the fibers and between strands of smaller fibers are filled with a nanoporous metal material such as silver particles, gold or aluminum or non-metal material. The projections are self-assembled. Each strand can have a first portion to absorb water and a second portion to repel water. The nano-particles are embedded in the strand by processes including soaking, spinning, casting, dipping, fluid-flow, padding, or spraying. Next, the substrate with the nano-particles is dried. Since the nano-particles are embedded in the strand, they are secured to the fabric or textile material in such way to remain after the substrate is washed. The application describes other embodiments including (a) wrinkle resistance, (b) molecular wires (imparts chemical, electrochemical or mechanical properties), (c) monolayer molecular array of short carbon nanotube molecules.

Claims 1 and 17 are illustrative; Claim 1 is direct to the article: A wash durable material, comprising: a substrate having strands with void spaces inside the strands; and nano-particles inside the strands filling at least a part of the void spaces with one or more projections from the void spaces through the strands on the substrate. Claim 17 is directed to the method: A method for fabricating a wash durable material, comprising: forming a substrate having strands with void spaces in the strands; filling at least a part of the void spaces with nanoparticles; and forming projections from the void spaces through the substrate.

The Examiner determined that prior art of Soane would have rendered prima facie obvious to one of ordinary skill in the art that (a) a substrate having strands with void spaces in the strands, or (b) nano-particles filling at least a part of the void spaces and projecting from the void spaces through the substrate.

On appeal, the Board of Patent Appeals and Interferences (BPAI) sided with the Examiner. Soane patents are directed to preparations useful for the permanent or substantially permanent treatment of textiles and other webs. The preparations comprise an agent or payload surrounded by or contained within a polymeric encapsulator that is reactive to webs, to give textile-reactive nanoparticles. By "textile-reactive" is meant that the agent or payload nanoparticle will form a chemical covalent bond with the fiber, yarn, fabric, textile, finished goods, or other web. So, the nanoparticles contained within the polymeric encapsulator have functional groups that form a strong chemical bond with the textile or other web fibers to improve retention of the nanoparticles within the textiles or other webs.

The BPAI rejected both Appellant's arguments that Soane (a) failed to show a substrate having strands with void spaces in the strands and between the strands and that (b) failed to show nano-particles filling at least a part of the void spaces and forming one or more projections on the substrate. The BPAI found, as to the first argument, that Soane's webs, which include "fibers and/or filaments; woven, knitted, stitch-bonded, and nonwoven fabrics derived from natural, man made and/or synthetic fibers and blends of such fibers; cellulose-based papers were made of the same types of materials as the Appellant's substrate. Thus, it appears that Soane refers to "fibers, filaments or structural components or elements" of the textile or other web as "fibers" like the Appellant's substrate Soane's substrate has strands with void spaces inside or in the strands. Regarding the second argument the BPAI noted that Soane's disclosure that the nanoparticles penetrate into the fiber indicates that the nanoparticles fill at least a part of the fiber's void spaces. Also, because Soane's nanoparticles are applied to the webs "by methods known in the art such as soaking, spraying, dipping, fluid-flow, padding, and the like" which are the same methods used by the Appellant it appears that like the Appellant's nanoparticles, Soane's nanoparticles fill at least part of the void spaces in strands and form one or more projections from the void spaces through the strands.

In summary, nanofiber scientists carrying on research that is a continuation of published scientific papers and patent applications that have been published or granted must be aware of the non-obviousness hurdle. Under patent law the invention must reveal something novel, including better and unexpected new ways of using it.

(1) Graham v. John Deere Co. of Kansas City, 383 U.S. 1, 17 (1966). The Graham factual inquiries include: (a) determining the scope and content of the prior art; (b) ascertaining the differences between the claimed invention and the prior art; (c) resolving the level of ordinary skill in the pertinent art; and (d) evaluating evidence of secondary considerations.
(2) KSR International Co. v.Teleflex Inc., 550 U.S. 398, 82 U.S.P.Q.2d 1385 (2007).
(3) Mark A. Lemley, Patenting Nanotechnology, 58 Stan. L. Rev. 601 (2005).

Please send your comments to Magda Carvalho at

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