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November 20, 2020by Marketing

Patent claims often recite structural limitations in combination with one or more properties. In the chemical arts, for example, a claim might recite a copolymer comprising certain monomer components, where the copolymer has certain rheological properties (e.g., melt flow rate, die swell).

In such cases, U.S. examiners often rely on the theory of inherency to fill gaps in the prior art. 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 (see, e.g., here and here).

Alternatively, U.S. examiners sometimes take the position that the claimed properties would result from an obvious optimization of a different property in the prior art. This issue is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Isaka.

Claim 1 recited (in part):

A tetrafluoroethylene/hexafluoropropylene copolymer having a melt flow rate measured at 372°C of 35.0 to 45.0 g/10 minutes and a die swell of -8.0% to 5.0%…

Claim 1 also recited a detailed method by which die swell was measured.

The examiner rejected claim 1 as obvious over a combination of two references. The primary reference (“Burch”) described a tetrafluoroethylene/hexafluoropropylene copolymer having a melt flow rate overlapping the claimed range. However, Burch was silent regarding the die swell of its copolymer.

The examiner relied on a second, evidentiary reference (“Krevelen”) for the property of die swell. The examiner found that Krevelen taught a correlation between the molecular weight of a polymer and its swelling properties. The examiner found that it would have been obvious to modify the molecular weight of the copolymer in Burch to optimize the melt flow properties of the copolymer. The examiner took the position that “[i]n modifying the melt flow properties…one would also be optimizing the die swell properties, as these properties are related through the polymer weight average molecular weight.” Thus, the examiner concluded that the die swell in claim 1 would result from an obvious optimization of melt flow properties in the prior art.

The Board disagreed with the examiner. Instead, the Board agreed with the applicant that “optimizing melt flow rate and molecular weight is not equivalent to optimizing die swell properties.”

In particular, the Board found that Krevelen taught that “die swell is modified by both molecular weight and molecular weight distribution.” The Board was not convinced that modifying the molecular weight by itself (i.e., without also accounting for the molecular weight distribution) would result in optimized die swell properties reading on claim 1.

The Board concluded that the examiner “did not sufficiently explain why a person of skill in the art would have had reason to adjust molecular weight distribution or why a person of skill in the art would otherwise have reason to adjust process variables in a manner that would reach claim 1’s recited die swell of -8.0% to 5.0%.” Accordingly, the Board reversed the obviousness rejection.

Takeaway: If an examiner takes the position that a claimed property would result from an obvious optimization of a different property in the prior art, it can be helpful to argue that optimizing the property in the prior art would not necessarily optimize the claimed property. As with arguments against inherency rejections, arguments in this situation are strengthened by technical explanations, optionally supported by experimental data.

Judges: Owens, Baumeister, Range


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October 30, 2020by Marketing

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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October 9, 2020by Marketing

U.S. patent claims usually contain the term “comprising.” This term indicates that an item in the claim must include certain specified components, but that the item also may include other, unspecified components. Alternatively, patent claims sometimes contain the term “consisting of.” This term indicates that an item in the claim is closed to unspecified components.

In between the open term “comprising” and the closed term “consisting of” is the term “consisting essentially of.” This semi-closed term indicates that an item in the claim is limited to the components specified in the claim “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention. In re Herz, 537 F.2d 549, 551-52 (CCPA 1976) (emphasis in original).

The semi-closed nature of “consisting essentially of” sometimes is attractive during patent prosecution. For example, if the prior art discloses the combination of components A, B and C, it might be difficult to distinguish a patent claim with an item comprising components A and B since the item is open to the unspecified component C by virtue of the open term “comprising.” Amending the claim so that the item consists of components A and B (rather than comprises components A and B) might distinguish the claim from the prior art, if the prior art requires component C. However, such an amended claim might be easy for a competitor to design around, simply by adding component D to components A and B in the competitor’s product. The term “consisting essentially of” can provide a middle ground, allowing a patent applicant to distinguish a claim from prior art without excessively narrowing the scope of the claim.

However, when using the term “consisting essentially of,” the patent applicant often must explain to the examiner what the “basic and novel characteristic(s)” of the claimed invention are, and why they would be “materially affect[ed]” if the claimed invention were to include an additional component from the prior art. This issue is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Nakajima.

Claim 1 in Nakajima recited:

A method of modifying starch, comprising subjecting a powdery mixture consisting essentially of starch and water-soluble hemicellulose at a weight ratio of 95:5 to 80:20 to moist-heat treatment at 100 to 200°C.

The examiner rejected claim 1 as obvious over two references, Yoshino in view of Narimatsu. The examiner relied on Yoshino for a method of subjecting starch to moist-heat treatment. The examiner acknowledged that Yoshino did not disclose water-soluble hemicellulose, and relied on Narimatsu for this component. Narimatsu described mixing water-soluble hemicellulose as a powder with wheat flour and starch. The examiner took the position that it would have been obvious to combine the water-soluble hemicellulose of Narimatsu with the starch of Yoshino, and then to treat the mixture of hemicellulose and starch with moist heat.

The applicant argued that the combination of Yoshino and Narimatsu would require the presence of wheat flour along with water-soluble hemicellulose and starch. Because of this, the applicant argued that the combination of these references would not satisfy the requirement that the powdery mixture consist essentially of starch and water-soluble hemicellulose.

In particular, the applicant argued that the presence of wheat flour would materially affect the basic and novel characteristics of the claimed invention. The applicant identified the basic and novel characteristics of the claimed invention as suppression of swelling or disintegration of starch granules. The applicant explained that including wheat flour with starch and water-soluble hemicellulose would not lead to such suppression. This explanation was supported by experimental data, submitted in a declaration, showing that samples containing wheat flour did not show the same inhibitory effect on swelling and disintegration of starch granules that was observed in samples without wheat flour.

Since the presence of wheat flour would materially affect the basic and novel characteristics of the claimed invention, the applicant argued that wheat flour should be excluded by the “consisting essentially of” phrase.

In response, the examiner contended that it would have been obvious to combine the water-soluble hemicellulose of Narimatsu with the starch of Yoshino, without including the wheat flour of Narimatsu.

The Board sided with the applicant. The Board found that Narimatsu taught adding water-soluble hemicellulose to a mixture of wheat flour and starch, but did not teach or suggest adding water-soluble hemicellulose to starch alone. The Board agreed that the applicant had provided sufficient evidence that including wheat flour in the powdery mixture of claim 1 would materially affect the basic and novel properties of the claimed invention. Accordingly, the Board found wheat flour to be excluded by the “consisting essentially of” phrase, and reversed the obviousness rejection.

Takeaway: The transitional phrase “consisting essentially of” provides a middle-ground between the open “comprising” and the closed “consisting of” phrases. When using the phrase “consisting essentially of,” applicants should be prepared to identify, on the record, what the basic and novel characteristics of the claimed invention are. Applicants also should be prepared to provide a technical argument, possibly supported by experimental data, explaining why the basic and novel characteristics would be materially affected if the claimed invention were to include an additional component from the prior art.

Judges: Franklin, Snay, Ren


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September 18, 2020by Marketing

For a prior art reference to be properly used in an obviousness rejection, the reference must be analogous art to the claimed invention. In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004). A reference is analogous art to the claimed invention if: (1) the reference is from the same field of endeavor as the claimed invention (even if it addresses a different problem); or (2) the reference is reasonably pertinent to the problem faced by the inventor (even if it is not in the same field of endeavor as the claimed invention). MPEP 2141.01(a), citing Bigio.


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August 28, 2020by Marketing

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.


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June 26, 2020by Marketing

On June 9, 2020, the Patent Trial and Appeal Board (“Board”) ­reversed the Examiner’s obviousness rejections in Ex parte Leibold. The obviousness rejections were based on the Examiner’s combination of two references: Petterson and Witzel. However, the Board found that it would not have been obvious to modify Petterson based on the teaching of Witzel, because such a modification would render Petterson inoperative for its intended purpose.