inherency Archives - ElementIP Law

“If you give me six lines written by the hand of the most honest of men, I will find something in them which will hang him.”

― Cardinal Richelieu (1585-1642)

On April 29, 2024, the Patent Trial and Appeal Board in Ex parte Wang (Appeal 2023-003255) affirmed an examiner’s single reference obviousness rejection of a claim to a process for stabilizing a protein against thermal inactivation:

A process for stabilizing a protein against thermal inactivation, comprising: binding a protein to the surface of a solid substrate; the protein bound to the surface by a linker moiety between an active group of the protein and said substrate, wherein the linker comprises a bond formed from one or more active groups selected from the group consisting of alcohol, thiol, carboxylic acid, anhydride, epoxy, and ester, and wherein said bond of the protein to the solid substrate stabilizes the protein against thermal inactivation.

This claim was finally rejected over Minier, characterized by the Examiner as disclosing a protein bound to a solid surface via “an alcohol linker active group bound to [a] metal substrate through a glutaraldehyde active group,” and thereby being inherently stabilized against thermal inactivation.

Appellants made two arguments. First, Appellants argued that surface bonding through a glutaraldehyde group was not included in or suggestive of the requirements of Claim 1. Second, they challenged the inherency finding.

With regard to the first argument, Appellants, in their Pre-Appeal Brief filed in direct response to the final rejection, characterized Claim 1 as reciting “[a] protein bound to the surface [of a solid substrate] by a linker moiety between an active group of the protein and said substrate, wherein the linker comprises a bond formed from [an] alcohol, thiol, carboxylic acid, anhydride, epoxy, and ester.” Then, in their Appeal Brief, Appellants characterized Claim 1 as reciting “[a] process for stabilizing a protein against thermal inactivation comprising binding a protein to the surface of a substrate; … by a linker moiety …. formed from one or more active groups selected from the group consisting of alcohol, thiol, carboxylic acid, anhydride, epoxy, and ester.” In both instances, Appellant argued that the reference’s use of a glutaraldehyde active group failed to disclose bonding a protein to a surface using one of their claimed linker moiety’s active groups. As for their second argument – inherent stabilization – Appellants argued that the reference nowhere discussed or recognized any thermal stabilization of the bound protein.

The Board was having none of it. Characterizing both issues as ones that “resolve based on a proper interpretation of claim 1” the Board walked Appellants through their surface/linker/active group claim language, demonstrating that in Claim 1 the linker’s active group need not be directly bound to the surface in the claim, just located “between” the protein and the surface. And with regard to thermal stability, the Board pointed to Appellants’ specification, which described thermal stability as a property necessarily flowing from the bond. Rejection Affirmed.

What went wrong? Well, Appellant was apprised of the Office’s interpretation of their claim language after the first rejection. Rather than discuss the case with the Examiner and come to agreement as to how to distinguish their clearly different invention from the applied art they barreled ahead with the same claim language, insisting that the Office see things their way. And when the Office didn’t, rather than seek reconsideration from the Examiner, Appellant filed a multi-issue Pre-Appeal Brief that simply upheld the rejection and provided no useful feedback. Full Appeal (with Oral Hearing) followed, after which the Board provided Appellant with the same answer the Examiner had given them two and a half years earlier: your invention is different, but your claims encompass the prior art.

The moral of the story? Differences aren’t important unless they are reflected in the claims. Listen to what the Examiner is saying – they look at the claims differently than you do. Sometimes, they are right. Oftentimes, simple amendments can address the issue, as here.

In Ex parte Perrot-Simonetta (Appeal 2023-000358), the Patent Trial and Appeal Board (“the Board”) reversed the Examiner’s obviousness rejection based on the principle of inherency.

The claim at issue was directed to a steel part having a particular elemental composition and microstructure and exhibiting certain properties. Specifically, in addition to the specific mechanical strength, elastic limit, and breaking elongation, the claimed steel part had “a constriction at break greater than 30%.”

The Examiner rejected the claim as obvious over Gao in view of Resiak and Han. The Examiner admitted that Gao was silent towards the constriction at break value but reasoned that since Gao described steel having overlapping composition, microstructure, and other mechanical properties, one skilled in the art would have found Gao’s steel necessarily had the recited constriction at break value. The Examiner additionally cited Resiak and Han, which described steel having the recited constriction at break value and admittedly “similar” but not identical compositions, to support her inherency/obviousness position.

The Appellant argued that Resiak and Han provided evidence showing that Gao’s steel did not necessarily possess the characteristics of the claimed product, and thus rebutted, not supported, the Examiner’s allegedly prima facie case. In particular, the Appellant noted that Resiak described a steel with the recited mechanical strength and constriction at break value but not the recited breaking elongation value. The Appellant further noted the different processing parameters for steel described in Gao, Resiak, and Han and argued that the secondary references could not provide any information on the constriction at break value of Gao.

The Board agreed with the Appellant and held that the combined prior art teaching did not support the Examiner’s finding that the recited properties were necessarily present in Gao’s steel. Judge Owens further noted in his concurring opinion that the Examiner had exercised impermissible hindsight.

Takeaway: A prima facie case of either anticipation or obviousness is established when the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes. However, as shown in Perrot-Simonetta, mere overlap in composition and structure may not be sufficient to establish that the claimed and prior art products are identical or substantially identical in structure or composition.

Judges: Terry J. Owens, Catherine Q. Timm, and Lilan Ren

In Ex parte Jung (Appeal No. 2021-003163), the examiner rejected the claims as obvious based on an inherency rationale. The PTAB reversed.

Independent claim 16 recited an inkjet set consisting of:

a black inkjet ink, a cyan inkjet ink, and two inkjet inks A and B… wherein

the inkjet ink A has a hue angle H* between 70 and 85 and a chroma C* between 30 and 80;

the inkjet ink B has a hue angle H* between 20 and 40 and a chroma C* between 30 and 80 …

The dispositive issue on appeal was whether the hue angle H* and chroma C* were inherent in the applied art.

The examiner cited a reference broadly disclosing mixtures of pigments, and including the specific pigments C.I. Pigment Orange 71, C.I. Pigment Yellow 139, C.I. Pigment Red 254, and C.I. Pigment Red 122 among a long list of suitable pigments. The examiner noted that these specific pigments were recited in the applicant’s dependent claims 19 and 21. Based on this, the examiner took the position that if these specific pigments were selected in the reference, the resulting inks “would intrinsically [i.e., inherently] have” the claimed H* and C* values.

The applicant argued that even if the specific pigments were selected in the reference, the claimed H* and C* values would not necessarily result. The applicant stated that these limitations “are not only achieved by selecting specific pigments, but also by the amounts of the pigments used and the weight ratio of the different pigments in the mixture.” Additionally, the applicant provided calculations of H* and C* values resulting from the examples of the reference, showing them to fall outside the claimed ranges. However, the examiner dismissed these calculations as “attorney argument and not evidence.”

The PTAB sided with the applicant. The PTAB found that “the use of the recited pigments alone is not adequate to guarantee that the H* and C* limitations are met” and that the ratio of different pigments mattered. Regarding the calculations provided by the applicant, the PTAB found that the examiner dismissed them in error (“There is no dispute that the calculations are based on examples disclosed by [the reference], and there is no dispute as to the accuracy of the calculations. Because [the reference] itself is evidence, the calculations made using the data from [its] examples should not have been disregarded as mere ‘attorney arguments.’”).

The PTAB acknowledged that the claims still might have been obvious if the reference “teaches or suggests combining pigments in a way (e.g., optimizing the weight ratios of different pigments) that would have resulted in H* and C* values within the scope of claim 16.” However, the PTAB found no such teaching or suggestion. While the reference taught that the pigments or mixture of pigments be present “in an amount of 0.1 to 20% by weight based on the total weight of the non-aqueous inkjet ink,” the reference provided no teaching or suggestion for weight ratios among different pigments. Accordingly, the PTAB reversed the obviousness rejection.

Takeaway: Whenever an examiner takes the position that a claimed property is inherent in the applied art, it is important to carefully evaluate embodiments of the applied art that might result in the claimed property. Inherency requires necessity, not merely possibility. That is, just because it might be possible for the applied art to satisfy a claimed property, that does not mean that the applied art necessarily satisfies the property. If the prior art does not necessarily satisfy the claimed property, then inherency has not been established.

Judges: Abraham, Kennedy, Gupta

In Ex parte Scheich (Appeal No. 2021-003495), the examiner rejected the claims as obvious over a combination of two references. The PTAB reversed.

Independent claim 1 recited:

A diffuser material of pore-containing quartz glass with

a chemical purity of at least 99.9% SiO₂,

a cristobalite content of not more than 1%, and

a density in the range of 2.0 to 2.18 g/cm³,

whereby at least 80% of the pores have a maximum pore dimension of less than 20 μm,

wherein the quartz glass is produced synthetically,

has a hydroxyl group content in the range of more than 200 wt. ppm, and

contains hydrogen in a concentration in the range of 10¹⁷ molecules/cm³ to 10¹⁹ molecules/cm³.

The examiner found that the primary reference (Moritz) satisfied each limitation of claim 1, except for being silent about a hydrogen concentration. The examiner cited a secondary reference (Ohama) describing a similar quartz glass. The quartz glass in Ohama was made from a silica powder having a hydrogen concentration overlapping the range recited in claim 1.

The examiner took the position that it would have been obvious to use Ohama’s silica starting material to prepare the quartz glass of Moritz. The examiner found that the hydrogen concentration of the finished product would be expected to be the same as that of the starting material because “[n]o evidence is given” to the contrary, and “Ohama provides no teaching or suggestion that the hydrogen is removed from the powder prior to or during formation of the inventive quartz material.”

In contrast, the applicant argued that the finished product in Ohama would not be expected to have the same hydrogen content as the starting material. In particular, the applicant argued that the sintering process in Ohama would be expected to reduce or remove molecular hydrogen from the starting material in forming Ohama’s finished product. As evidence, the applicant cited a portion of Ohama describing that the hydrogen in the starting material “react[s] with free oxygen to form OH groups, and the OH groups are fixed in the glass to suppress pore expansion from occurring.”

The PTAB agreed with the applicant. The PTAB found that “Ohama discloses that the hydrogen in Ohama’s starting material reacts with oxygen in a way that would consume Ohama’s hydrogen, such that Ohama’s final quartz glass product would not have the same hydrogen concentration as its silica powder starting material.” In a footnote, the PTAB acknowledged that the broad range of hydrogen concentration in Ohama’s starting material might allow for significant removal of hydrogen while still satisfying the claimed range for the finished product. However, since the examiner made no findings as to an expected magnitude of the decrease of hydrogen, the PTAB reversed the obviousness rejection.

Takeaway: U.S. examiners often make inferences beyond the explicit teachings of prior art references. These inferences usually are phrased in terms of what would have been expected based on the technical knowledge of a person of ordinary skill in the art. Sometimes applicants can rebut such inferences with evidence of their own. This evidence can be provided in the form of a Rule 132 Declaration, or, as in Ex parte Scheich, by reference to portions of the applied art.

Judges: Best, Kennedy, Cashion Jr.

In Ex parte Watabe, No. 2020-005979 (P.T.A.B. Sep. 28, 2021), the Patent Trial and Appeal Board (PTAB) reversed an Examiner’s rejection of claims directed to a solar cell assembly comprising a recess having a particular flatness. The issue in the case, both on appeal and at the examiner level, was whether the applied prior art inherently possessed the necessary flatness.

During prosecution, the Examiner presented several technical reasons explaining why the claimed flatness was inherent in the prior art, including a detailed comparison of the process used in the prior art with that of the inventors and, citing MPEP 2112.01, invited Applicant to provide evidence showing that the prior art did not necessarily possess the claimed flatness feature. Applicant responded to both the first and final rejection with a detailed analysis of their own, only to be denied in favor of the Examiner’s analysis, necessitating appeal.

In its Appeal Brief, Applicant expanded (from 3 pages to 5 pages) its analysis, and expanded it even further in its Reply Brief (to 7 pages in length). In reversing the rejection, the PTAB accepted Applicant’s analysis as showing a difference in methodologies between the specification and the applied reference, and found this persuasive on the issue whether the reference necessarily possessed the claimed flatness (note that the PTAB often makes the opposite decision).

Takeaway: While Applicant eventually prevailed in this case, it was a close call – the PTAB accepted “attorney argument” as persuasive on inherency, seemingly focusing on methods of preparation rather than final products. Wouldn’t it have been easier to file a Declaration in response to the first rejection, making it clear that the reference did not possess the required flatness, thereby providing evidence that the Examiner could rely on (and had asked for)? In this case there was an interview, two responses, an Appeal Brief, and a Reply Brief. While ultimately successful, it seems as though prosecution could have been short-circuited very early in the process with the right Declaration.

Judges: B. Franklin, B. Range, D. Dennett

In Ex parte Easson (Appeal 2020-001129), the Patent Trial and Appeal Board (“Board”) reversed the Examiner’s obviousness rejection because the Examiner failed to show the prior art composition with the required components necessarily had the claimed properties.

Claim 21 was illustrative and read:

A directly compressible tableting composition, comprising 50-85% by weight of anhydrous calcium hydrogenphosphate, 10-40% by weight of mannitol and 5-20% by weight of sorbitol, wherein said composition has a flow angle in the range of 29 to 33.4° and a bulk density in the range of 0.56 to 0.77 g/ml with a tapped density in the range of 0.73 to 0.92 g/ml.

The Examiner rejected claim 21 as obvious over Yokoi in view of Ranchhordas and Reiff. In particular, the Examiner found that Yokoi taught a powdered composition for tablets that had the same components in overlapping amounts. The Examiner contended that the claimed flow angle range was an inherent property of the claimed composition and thus the composition described in Yokoi must have the same flow angle. The Examiner found that Ranchhordas and Reiff described bulk densities of anhydrous calcium hydrogen phosphate and sorbitol, respectively, both of which overlapped with the claimed bulk density range. The Examiner thus concluded the mixture of the two had the claimed bulk density. Regarding the tapped density range, although the Examiner admitted that the references did not teach the property, he reasoned that “[because] all other properties are overlapping[,] the tapped density would be expected to overlap as well.”

Appellant argued that the Examiner misapplied the law of inherency and that the recited properties were additional limiting requirements of the claimed invention that would not be necessarily possessed by any composition with the recited components. The Board agreed.

In particular, regarding the bulk density, the Board noted that the claimed composition was a mixture of three components and that there was no evidence in the record disclosing the bulk density of mannitol, which was a component other than anhydrous calcium hydrogenphosphate and sorbitol. Also, the Board pointed out that claim 21 encompassed a composition containing as little as 50 wt% of anhydrous calcium hydrogenphosphate, 10 wt% of mannitol, and 5 wt% of sorbitol; that is, the claimed composition could contain as much as 35 wt% of unspecified ingredients with unknown bulk densities. The Board thus concluded that it was not necessarily true that any composition encompassed by claim 21 would have the claimed bulk density.

The Board further found evidence of record that contradicted the Examiner’s inherency conclusion. Specifically, the Board found Appellant’s specification described five compositions containing proportions of anhydrous calcium hydrogenphosphate, mannitol, and sorbitol within the recited ranges; however, two of these compositions had bulk densities and tapped densities that were too high to fall within the specified ranges.

Takeaway: When faced with a composition claim containing property limitations, examiners often assert the properties are inherent if they find a prior art composition satisfying the claimed composition limitations. However, that a property may occur or be present in the prior art is not sufficient to establish inherency. To rely on a theory of inherency, an examiner “must provide a basis in fact and/or technical rationale to reasonably support the determination that the allegedly inherent characteristic necessarily flows from the teachings of the applied prior art.” Ex parte Levy, 17 U.S.P.Q. 2d 1461, 1464 (B.P.A.I. 1990). As illustrated by Easson, an inherency argument lacking such reasoning does not establish a prima facie case of anticipation and/or obviousness, particularly when there is counter evidence showing the properties are additional distinguishing requirements that are not merely results of the composition limitations.

Judges: D. E. Adams, E. B. Grimes, and J. N. Fredman

Ex parte Yim, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing whether claimed properties were inherent in prior art compositions.

In Ex parte Yim, the claim at issue was directed to a resin. However, the resin was not defined by structure or composition. Instead, only properties of the resin were recited in the claim: (a) content of water-soluble fraction, (b) absorbency against pressure property, and (c) water-soluble fraction shear index property. Independent claim 16 is reproduced in part below:

16. A water-absorbing resin, in which

[a] a content of a water-soluble fraction is 15 wt% or less based on the total weight of the resin,

[b] an absorbency against pressure at 0.3 psi with respect to a saline solution including sodium chloride at 0.9 wt% is 25 g/g or more, and

[c] a water-soluble fraction shear index A/B represented by the following Expression 1 is in a range of 0.1 x 10^-5 (s) to 10 x 10^-5 (s)….

In rejecting the claim, the examiner relied on a single prior art reference that disclosed a water-absorbing resin but did not disclose the properties recited in the claim. Both the prior art reference and the application on appeal disclosed forming water-absorbing polymers by polymerizing and crosslinking an acrylic acid monomer. The examiner asserted that, in view of the similarities in starting materials and processing steps used in the prior art reference and the application on appeal, the properties in the claim were inherent in the water-soluble resins of the prior art reference.

The examiner further asserted that, even if applicant could demonstrate that none of the water-soluble resins exemplified in the prior art reference had the claimed properties, it would have been obvious to tune the reactions in the prior art references to optimize absorbance/solubility characteristics.

The examiner’s inherency arguments turned, particularly, on the examiner’s determination that the prior art reference used two internal crosslinkers to crosslink an acrylic acid, which was the same or similar to the method disclosed in the application on appeal. Applicant countered by arguing, inter alia, that the steps of the prior art method were different such that the two internal crosslinkers were reacted together before being added to acrylic acid, which could not be said to necessarily result in the claimed properties.

The PTAB found that the examiner had made a good argument that the processes of the prior art reference would result in the claimed properties, such that it became applicant’s burden to show that the exemplified resins did not possess the claimed properties. The PTAB also noted that applicant failed to present arguments rebutting the examiner’s fallback assertion that optimizing the properties of the prior art resin would have been a mere matter of routine experimentation to a skilled artisan. Thus, the examiner’s rejection was affirmed.

Takeaway: Parameter or property claims can be valuable in a patent directed to a material or chemical composition. By keeping strict compositional or structural limitations out of a claim, materials or compositions not contemplated at the time of filing may be encompassed by the claim. Further, if claimed parameters/properties are not explicitly disclosed in the prior art, it can be difficult for a third party to confidently analyze the validity of the claim. However, these advantages in a patent claim can be challenges during examination. While some parameter/property claims “sail through” examination, Ex parte Yim shows that an applicant should be prepared to reproduce prior art examples and provide evidence to rebut assertions of routine optimization to obtain allowance.

Judges: Timm, Smith, Range

Ex parte Whalen, is a 2008 decision of the Board of Patent Appeals and Interferences (BPAI) that is listed among the Patent Trial and Appeal Board’s (PTAB) precedential decisions. Ex parte Whalen, is indicated by the PTAB to be precedential as to “Anticipation – 35 U.S.C. § 102… Inherency… evidence and reasoning” and “Obviousness – 35 U.S.C. § 103… Rationales… optimizing a variable.”

According to the PTAB’s Standard Operating Procedure, “[a] precedential decision is binding Board authority in subsequent matter involving similar facts or issues.”

In Ex parte Whalen, the BPAI considered whether an examiner met his burden in asserting inherency, or alternatively routine optimization, of a claimed viscosity that was not explicitly disclosed in the prior art.

Independent claim 1 was identified as a representative claim:

A composition capable of embolizing an aneurysm at a vascular site comprising:

(a) a biocompatible polymer;

(b) a biocompatible contrast agent wherein a sufficient amount of said contrast agent is employed in said composition to effect visualization in vivo; and

(c) a biocompatible solvent which solubilizes said biocompatible polymer

wherein a sufficient amount of said polymer are [sic] employed in said composition such that, upon delivery to a vascular site, a polymer precipitate forms which embolizes said vascular site; and

further wherein the biocompatible polymer has a molecular weight sufficient to impart to the composition a viscosity of at least about 150 cSt at 40° C.

The claim was rejected as anticipated or obvious over several prior art references. All of the cited prior art references disclosed combinations of components (a), (b), and (c) in compositions for embolizing an aneurysm at a vascular site, but none explicitly disclosed a composition having “a molecular weight sufficient to impart to the composition a viscosity of at least about 150 cSt at 40° C.” The examiner argued that the prior art compositions inherently possessed the claimed viscosity or, alternatively, it would have been obvious to a skilled artisan to “optimize” the prior art compositions by increasing their viscosity to the level recited in the claims.

It was undisputed that the prior art disclosed compositions including components (a), (b), and (c) in amounts overlapping those in the specification and claims of the application on appeal. However, the only disclosure in the prior art of viscosity was of a preferred composition having a viscosity much lower than the viscosity specified in claim 1. The BPAI found that the examiner had not met his burden in establishing inherency. The BPAI stated that, even if some of the compositions encompassed by the prior art’s broad disclosure might have the claimed viscosity, “that possibility is not adequate to support a finding of inherent anticipation.” The BPAI noted that the examiner did not provide evidence or scientific reasoning to show that any specific composition disclosed in the prior art was within the scope of claim 1.

The examiner’s obviousness position rested on the assertion that a skilled artisan would have been motivated to optimize the viscosity of the prior art composition to achieve “the safest clinical outcome and avoiding transvenous passage.” The BPAI noted that the prior art disclosed “adjustment of the viscosity of the composition as necessary for catheter delivery can be readily achieved by mere adjustment of the molecular weight of the copolymer composition.” However, the prior art also disclosed that low viscosity was a desired property in embolic compositions and, as noted above, the only disclosed viscosity in the prior art was much lower than that of claim 1.

Taking the foregoing facts into consideration, and mindful of the Supreme Court’s (then) recent command of “flexibility” in the obviousness inquiry (KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398 (2007)), the BPAI nonetheless concluded that the examiner had not met his burden. Particularly:

… when the prior art teaches away from the claimed solution as presented here… obviousness cannot be proven merely by showing that a known composition could have been modified by routine experimentation or solely on the expectation of success; it must be shown that those of ordinary skill in the art would have had some apparent reason to modify the known composition in a way that would result in the claimed composition.

That is, the examiner was required but failed to provide an “explanation based on scientific reasoning” that would support the conclusion that a skilled artisan would have considered it obvious to optimize the prior art compositions by increasing their viscosity to the level recited in the claims.

Ex parte Whalen was decided by an expanded five-judge panel, instead of the usual three-judge panel. The Chief Administrative Patent Judge was one of the deciding judges. According to the PTAB’s Standard Operating Procedure, “[a]n expanded panel is not favored and ordinarily will not be used… [a]n expanded panel may be used, where appropriate, to secure and maintain uniformity of the Board’s decisions…”

Takeaway: One of the challenges of prosecuting composition claims (combinations of known components) is the seeming ease with which an examiner can assert that a property not explicitly disclosed in the prior art is inherent and/or would have been readily achieved by a skilled artisan as a matter of routine optimization. Of course, the burden-shifting framework for examination of claims reciting properties is reasonable; however, there remains some burden on the examiner. Rejections based on inherency or routine optimization require that the examiner provide “scientific reasoning” consistent with the overall teaching of the prior art. Conclusory or thinly reasoned assertions of inherency or routine optimization thus provide an avenue for challenge.

Judges: Fleming, Lane, Grimes, Lebovitz, Prats

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

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

Older Posts

When to Appeal?

When to Appeal?

Is Inherency Established If Overlap in Composition and Structure Is Found?

Effective Showing of Non-Inherency

PTAB Reverses Obviousness Rejection, Finding Claimed Component Not Necessarily Present in Prior Art Finished Product

PTAB Accepts Attorney Argument as Persuasive on Inherency

Obviousness Rejection Reversed Because Property Limitations Are Not Inherent

Parameter/Property Claims Can Be Valuable In Patents But Challenging During Examination

Examiner Burden in Showing Inherency and Routine Optimization – Past “Precedential” PTAB Decisions

PTAB Reverses Obviousness Rejection Based on Optimization of Different Property

PTAB Reverses Examiner’s Inherency Rejection Due to Conflicting Evidence

USPTO Withdraws Proposed Terminal Disclaimer Rule

USPTO Further Delays Non-DOCX Fee Until January 17, 2024