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October 30, 2020by Matthew Barnet1

U.S. patent examiners sometimes rely on the theory of inherency to fill gaps in the prior art. This usually occurs when patent claims recite structural limitations in combination with one or more properties. If the prior art describes the claimed structural limitations, but not the claimed properties, examiners often take the position that the claimed properties would be inherent in the structure of the prior art, even though the properties are not explicitly described in the prior art.

Under U.S. law, however, the mere possibility that the prior art possesses the claimed properties is insufficient to establish inherent anticipation or obviousness. Instead, to establish inherency, the examiner must provide a rationale that the claimed properties are necessarily present in the prior art.

This issue is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Liu. The claims at issue recited:

A polymer composite composition comprising:

an eggshell component, wherein the eggshell component possesses a lipid-protein structure substantially similar to that of the eggshell from which the eggshell component is derived, and wherein the eggshell component is substantially free of eggshell inner membrane material; and

a polymer component.

The inventors discovered that an improved polymer composite could be produced by using an eggshell component possessing its original lipid-protein structure and being free of the inner membrane of the original eggshell. The original lipid-protein structure was thought to maintain the hydrophobicity of the eggshell component when dispersing the eggshell component as a powder into the polymer component.

The examiner rejected the claims as obvious over a combination of references. The primary reference (“New”) described separating pulverized eggshells from their attached membranes using airflow. A secondary reference (“Minagoshi”) described combining eggshell powders in polymeric rubber compositions. The examiner took the position that it would have been obvious to use the pulverized eggshells from New as the powder in Minagoshi, to obtain the claimed polymer composite composition.

The references did not specifically describe that the eggshell component possessed a lipid-protein structure substantially similar to that of the eggshell from which the eggshell component was derived, as recited in the claims. To fill this gap in the prior art, the examiner took the position that the eggshell powder produced in New would inherently retain the original lipid-protein structure. This position was based on New allegedly “using airflow without harsh chemicals or high temperatures” to separate the membrane from the eggshells. Since the reference was silent with respect to its processing temperature, the examiner took the position that it was performed at room temperature.

The applicant provided a declaration explaining that “[e]ggshell can be denatured at a relatively low temperature” and “temperatures above 41°C will break the interactions of many proteins and denature them.” The applicant acknowledged that New did not specifically disclose the temperature used in its process, but argued that the high-speed airflow in this process would result in a temperature above 41°C. Such a temperature would denature the eggshell, such that it would not possess the lipid-protein structure recited in the claim.

Thus, the examiner argued that New used a temperature below 41°C (resulting in a product meeting the claimed limitation), whereas the applicant argued that New used a temperature above 41°C (resulting in a product not meeting the claimed limitation).

Considering these conflicting arguments and evidence, the Board found the examiner’s inherency position untenable. The Board found that “it is uncertain what temperature New’s process suggests. The preponderance of the evidence of record, therefore, does not support a finding that New’s process inherently takes place at a temperature of less than 41°C.” The Board concluded that “[t]he evidence, therefore, also does not support a finding that New’s process necessarily results in an eggshell composition which possesses a lipid-protein structure substantially similar to that of the eggshell from which the eggshell component is derived,” as recited in the claims. Accordingly, the Board reversed the obviousness rejections.

To be clear, the Board did not find that New’s process was inherently performed at a temperature above 41°C, as applicant argued. Instead, the Board found that the evidence was inconclusive as to what temperature the process occurred. This uncertainty in temperature was the key to the Board’s decision on inherency. As the Board noted, “[i]nherency…may not be established by probabilities or possibilities. The mere fact that a certain thing may result from a given set of circumstances is not sufficient” (citing In re Robertson, 169 F.3d 743, 745 (Fed. Cir. 1999)). Even though it was possible that New’s process was performed at a temperature below 41°C, as alleged by the examiner, this possibility was insufficient to establish that the temperature inherently was below 41°C.

Takeaway: Inherency requires necessity, not merely possibility. That is, just because it might be possible for the prior art to satisfy a claimed property, that does not mean that the prior art necessarily satisfies the property. If the prior art does not necessarily satisfy the claimed property, then inherency has not been established. When there is conflicting evidence, some in support of a claimed property being present and some in support of a claimed property being absent, this conflict itself can support an argument against inherency.

Judges: Gaudette, Wilson, Range


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September 4, 2020by Beau Burton

On August 19, 2020, the Patent Trial and Appeal Board (“Board”) issued a decision in Ex parte Boutillier (Appeal No. 2020-000348) reversing an Examiner’s obviousness rejection for failing to establish that the prior art inherently taught a claimed property.

The independent claim in Boutillier required a composition that included an elastomeric phase formed of a block copolymer, where the block copolymer had “a water solubility of less than 0.5 g/l.”

The prior art cited by the Examiner disclosed water soluble block copolymers that could be formed from the same monomers and in the same proportions recited in the Applicant’s dependent claims (e.g., acrylic and/or methacrylic monomers). Although the prior art did not disclose the water solubility of the block copolymer, the Examiner reasoned that “[the] instantly claimed water solubility can be made from the disclosure of [the prior art]” because the copolymer of the prior art “can include the same monomers as instantly claimed, within the same weight ranges as instantly claimed.”

The Applicant disagreed with the Examiner’s reasoning because the block copolymers of the prior art were characterized as being water soluble, and thus, would not be expected to have a water solubility less than 0.5 g/l.

The Board sided with the Applicant. The Board found that even though it was undisputed that the prior art taught block copolymers that could be prepared from the same monomers claimed by the Applicant, the prior art expressly taught its block copolymers were water soluble. The mere fact that it might be possible to prepare a block copolymer with a water solubility of less than 0.5 g/l with the monomers disclosed in the prior art was insufficient to establish the inherency of this feature.

The Board emphasized that the “very essence of inherency is that one of ordinary skill in the art would recognize that a reference unavoidably teaches the property in question.” Agilent Technologies, Inc. v. Affymetrix, Inc., 567 F.3d 1366, 1383 (Fed. Cir. 2009). And, in this case, the water solubility of less than 0.5 g/l was not “unavoidable or the natural result following [the prior art’s] teaching.”

Takeaway: Examiners often rely on the rationale that “if the prior art teaches the identical chemical structure, the properties applicant discloses and/or claims are necessarily present.” In re Spada 911 F.2d 705 (Fed. Cir. 1990). However, this rationale breaks down in two situations. The first is where there is a broader teaching in the prior art, as in this case, that suggests the property would not necessarily be present despite similarities in the chemical structures. The second is where there is a generic disclosure in the prior art that encompasses–but does not specifically teach–the identical structure claimed. In this situation, a presumption of inherency can be rebutted by showing that one or more species falling within the generic disclosure do not exhibit the claimed property.

Judges: E. Grimes, F. Prats, L. Ren


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August 28, 2020by Matthew Barnet

Patent claims often recite structural limitations in combination with one or more properties. For example, a product claim might recite a composition comprising three components, where one of the components is specified as having certain physical properties. In such cases, U.S. patent examiners often reject the claims as either anticipated or obvious based on prior art describing the structural limitations but not describing the properties.