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CIP Application Claiming Genus Is Denied Benefit of Earlier Filing Date of Application Disclosing Species

January 06, 2004

Decision icon Decision

Last Month at the Federal Circuit - February 2004

Judges: Clevenger (author), Dyk, and Prost

In In re Curtis, No. 03-1215 (Fed. Cir. Jan. 6, 2004), the Federal Circuit affirmed a decision of the Board that certain claims of U.S. Patent No. 5,209,251 (“the ‘251 patent”) in a merged reissue and reexamination proceeding lacked novelty.

The ‘251 patent is directed to dental floss made of polytetrafluoroethylene (“PTFE”) filaments covered with frictionenhancing coatings. The coatings provide the floss with a coefficient of friction (“COF”) of at least 0.08. This value falls within the “sweet spot” that makes floss not too sticky in the teeth and not too slippery in the hands.

The inventors, John P. Curtis et al. (collectively “Curtis”), received the ‘251 patent at the end of a series of CIP applications, the last being filed on July 11, 1991. Curtis then filed a reissue application adding claims to dental floss unrestricted by any COF value. W.L. Gore & Associates, Inc. (“Gore”) soon after requested reexamination of the claims of the ‘251 patent. The PTO merged the two proceedings.

The Examiner and Board handed Curtis a novelty rejection in view of one of his own related European patent applications that was published on October 4, 1989, more than one year before the July 1991 filing date of the application that led to the ‘251 patent. The European counterpart discloses PTFE filaments coated with microcrystalline wax and having the desired COF value. To sidestep this publication, Curtis sought priority to an earlier U.S. Application No. 07/282,962 (“the ‘962 application”), filed on December 2, 1988. As with the European case, the ‘962 application discloses PTFE filaments coated with microcrystalline wax. The Examiner and Board rejected Curtis’s request for priority, concluding that the disclosure of “microcrystalline wax” (a species) in the ‘962 application does not provide written-description support for “friction enhancing coatings” (a genus) used in the ‘251 patent claims.

Curtis argued that the ‘962 application disclosure of a microcrystalline wax coating conveyed to one skilled in the art a PTFE dental floss having a “friction enhancing coating.” The reason that the ‘962 application only disclosed microcrystalline wax in particular, Curtis argued, was that it was the most commonly used and cheapest dental-floss coating at the time of filing. Curtis believed that the decision of In re Smythe, 480 F.2d 1376 (C.C.P.A. 1973), squarely applied to his situation. In Smythe, the applicants sought, and were granted, priority benefit for the genus of “inert fluid” (encompassing both an inert gas and an inert liquid) in view of an earlier disclosure of only an “inert gas.”

The Board disagreed. Nowhere in the ‘962 application did Curtis name a suitable friction-enhancing coating for a PTFE dental floss other than microcrystalline wax. The ‘962 application itself expressed the “surprise” of the inventors to find that microcrystalline wax in particular, and from among different waxes, adheres to PTFE filaments, unexpectedly resulting in important benefits. In responding to an obviousness rejection, Curtis argued that “[t]he only wax that will effectively bind to PTFE is microcrystalline wax,” and “[w]hat can be adhered to PTFE surfaces can be determined only by trial and error . . . . There are no expectations of what will work. There is no obvious solution.”

The Federal Circuit concluded that the record contained considerable evidence demonstrating that microcrystalline wax was in fact the only friction-enhancingcoating conveyed in the ‘962 application. The unpredictability in performance of friction-enhancing coatings, argued by Curtis to distinguish the prior art, undermined any reliance on In re Smythe. In the case of the Curtis invention, the Federal Circuit concluded that almost all the evidence points to the conclusion that a person of ordinary skill would be hardpressed to instantly recall any other species of friction-enhancing coatings that would adhere to PTFE. Even if a skilled person could do so, the writtendescription problem would remain because the ‘962 specification unequivocally identifies microcrystalline wax as unique and different in its ability to bind to PTFE. By definition, such a disclosure does not convey the knowledge that the overall genus of “friction enhancing coatings” has the same qualities. The Federal Circuit, therefore, denied Curtis the benefit of the ‘962 application filing date and affirmed the rejection of the claims.