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An obviousness rejection was recently reversed by the Patent Trial and Appeal Board (PTAB) by the panel of Administrative Patent Judges (APJs) authored by Debra L. Dennett, and further including Jeffrey W. Abraham and Avelyn M. Ross in U.S. Appl. No. 17/395,422 (the 422 Application). The PTAB reversed the obviousness finding of examiner Justin Fischer, supported by Supervisory Patent Examiner (SPE) Katelyn W. Smith, and Quality Assurance Specialist (TQAS) Colleen P. Dunn, on the alleged obviousness of the claims over a combination of three to five references, three of which were the applicant-appellant's own prior art. The main claim on appeal recited
[a] heavy duty tire comprising a carcass extending from a tread part through a sidewall part to a bead core of a bead part and a belt layer arranged outside in a tire radial direction of the carcass and inside of the tread part,
wherein the belt layer is formed by a belt ply comprising a first belt layer, a second belt layer, and a third belt layer which are laminated in order from inside in the tire radial direction,
wherein the tread has a plurality of main grooves extending continuously in a tire circumferential direction,
wherein the tread comprises a cap rubber layer constituting a tread surface and a base rubber layer adjacent to inside in a tire radial direction of the cap rubber layer,
wherein the cap rubber layer and the base rubber layer are composed of a rubber composition comprising a rubber component,
wherein the rubber component constituting the cap rubber layer comprises 65 to 90% by mass of an isoprene-based rubber and 10 to 35% by mass of a butadiene rubber,
wherein the rubber composition constituting the cap rubber layer comprises 45 to 110 parts by mass of silica having a nitrogen adsorption specific surface area (N2SA) of 180 m2/g or more based on 100 parts by mass of the rubber component,
wherein a ratio of a storage elastic modulus Ee' of the rubber composition constituting the cap rubber layer at 70°C is 4.4 to 7.8 MPa,
wherein a tan δ of the rubber composition constituting the base rubber layer at 70°C is 0.04 to 0.07,
wherein an elongation at break of the rubber composition constituting the base rubber layer is 380% or more,
wherein a ratio of the storage elastic modulus Ec' of the rubber composition constituting the cap rubber layer at 70°C to a storage elastic modulus Eb' of the rubber composition constituting the base rubber layer at 70°C (Ec'/Eb') is 1.1 to 1.7, and
wherein, when, in a tire meridional cross section including a tire rotation axis, a thickness of the cap rubber layer on a normal line extending from an end of a tire rotation axis direction of the third belt layer down to the tread surface is Te, a thickness of the cap rubber layer at a position half a distance from a tire equatorial plane to the end of the tire rotation axis direction of the third belt layer is Tm, and a thickness of the cap rubber layer on the tire equatorial plane is Tc, Te is smaller than Tc, and Te, Tm, and Tc satisfy the following Mathematical expression (3) and (4):
0.85 ≤ Tc/Tm ≤ 1.15 (3)
1.00 < Tm/Te ≤ 1.15 (4).
The 422 Application was filed August 5, 2021, with broader claims than those appealed, the claims being first rejected on October 20, 2022. A response filed January 20, 2023, amending claim 1 to include the final clause in the appealed claim (from original claim 2), overcame the initial rejection, but the claims were rejected over a new set of references on January 30, 2023, including a reference (Numata) used in the rejection appealed.
The applicant added the penultimate clause (from original claim 8) into the above-indicated, appealed claim in response to the final rejection on April 27, 2023, which the examiner entered, but continued to reject the claims over the January 30th references. The applicant filed an appeal brief on August 28, 2023, providing evidentiary references—later decisive—against the examiner's inherency-like position that
the cap rubber of Numata is broadly disclosed as being harder than the base rubber (column 5, lines 4+) - this suggests that the modulus of the cap rubber would similarly be greater than that of the base rubber (ratio greater than 1) given the common relationship between hardness and modulus.
The applicant-appellant evidenced in the appeal brief that even if the rubber hardness increases, the storage elastic modulus E' of the rubber does not necessarily increase—even that there can be an inverse relationship between hardness and storage elastic modulus. (Likely because the references were publically available patent literature, these evidentiary references were considered by the examiner on appeal, even though they were not cited prior to appeal.)
The examiner re-opened prosecution on September 27, 2023, rejecting the claims over a combination of four references, three of which originated from the applicant. In the September 27th rejection, the examiner persisted in the argument that “[w]hile Numata fails to disclose a relationship between the respective storage moduli, it is well recognized that hardness and storage modulus generally have a positive correlation to one another (e.g. greater storage modulus generally correlates with greater hardness).” The examiner believed to support his rejection by citing to a new reference, Nagai, which the examiner argued “provides an example of cap-base design and describes the general relationship between hardness and storage modulus,” in ¶ [0033].
The applicant responded on December 27, 2023, by reciting the mass percentages of the isoprene-based rubber and the butadiene rubber as presented in the 6th clause above-indicated, ultimately-appealed claim, arguing that these amounts were not specifically shown by the combination of cited art, that the office action applied improper hindsight analysis, that the claims provide unexpectedly superior results, and that none of the cited art described the claimed relationship between a rubber hardness Hs measured under specific conditions and a storage modulus (“a ratio of the storage elastic modulus Ec' of the rubber composition constituting the cap rubber layer at 70°C to a storage elastic modulus Eb' of the rubber composition constituting the base rubber layer at 70°C (Ec'/Eb') is 1.1 to 1.7”). The applicant again noted that the evidentiary references from the first appeal, WO 2022/149491, US 2018/0051163, and JP 2014-185231 also contain examples showing an inverse relationship between hardness and storage elastic modulus.
The examiner again rejected the claims on January 18, 2024, over a combination of four references, and optionally a fifth, exchanging one reference from the September 27th rejection for a reference from the April 27, 2023, office action. The examiner persisted in the inherency-like argument, asserting that (emphasis from the author)
Numata (Paragraph 32)1 and Nagai (Paragraphs 152, 333, and 424) recognize the known use of harder rubber compositions for the tread cap (ground contacting tread layer), as compared to the tread base (non-ground contacting tread layer). This general relationship would have been expected to be present in the modified tire of Kunisawa (consistent with cap-base designs). Nagai specifically provides an example of cap-base design and describes the general relationship between hardness and storage modulus, with increased hardness corresponding with increased storage modulus (Paragraph 33). Even if such a relationship is not inherent, it appears that such a relationship is present in a vast majority of rubber compositions. Also, Nagai specifically motivates one having ordinary skill in the art at the time of the invention to form the cap-base in the modified tire of Kunisawa with different modulus values in accordance to the claimed invention (harder rubber (larger storage modulus) in cap portion promotes steering stability and softer rubber (smaller storage modulus) in tread base layer promotes ride comfort). As such, one of ordinary skill in the art at the time of the invention would have found expected a ratio in the modified tire of Kunisawa to be greater than 1 and fully encompass the broad range of the claimed invention, there being no conclusive showing of unexpected results for a ratio between 1.1. [sic] and 1.7.
On April 18, 2024, the applicant attempted a response narrowing the silica content in clause 7 (from 30 parts by mass or more) and including clauses 8 and 10 of the above-indicated, ultimately appealed claim, but the examiner required an RCE entry. The applicant filed an RCE for entry of the amendment on May 17, 2024, arguing that the patchwork cited art failed to disclose particular features and that the claims provided unexpectedly superior results. The claims were again rejected on May 28, 2024, rejecting all features by picking and choosing elements from any of four to five cited references and replicating the above inherency-like argument in reliance on Numata's ¶ [0032] and Nagai's ¶¶ [0015], [0033], and [0042].
On November 26, 2024, after a remailing of a corrected office action on June 26, 2024, an appeal brief was filed arguing that (A) the cited art failed to disclose or suggest the claimed amount or type of silica claimed in the cap rubber; (B) the claimed Base rubber layer and Cap rubber layer leads to unexpected results; (C) the cited art failed to disclose or suggest the claimed storage elastic modulus ratio, i.e., 1.1 to 1.7—the prevailing argument—relying again on the same evidentiary references provided in the initial appeal, showing that the claimed ratio was not necessarily present in the cited art.
The examiners mailed an Examiner's Answer February 10, 2025, premising obviousness on a recomposition of the claim from three references because (1) the components were known/available in the art; (2) no unexpected results had been shown; and (3) the claimed storage elastic modulus ratio, i.e., 1.1 to 1.7, was inherent. The obviousness of the recombination of known parts (1) was not an implausible USPTO argument, given that no evidence was provided that the combination was unpredictable, technically risky, or otherwise not expected to succeed, even if the number of combinations to arrive at the claimed composition may have been large. The lack of unexpected results (2) commensurate with the claim scope was also plausible from a USPTO perspective, since the standard is somewhat subjective and is often best arrived at in coordination with the examiner. However, regarding the alleged inherency (3) the (experienced) examiners argued that (emphasis from the examiner)
[a]s set forth in the pending rejection, treads formed with a cap-base structure are conventionally formed with harder rubber compositions for the tread cap (ground contacting tread layer), as compared to the tread base (non-ground contacting tread layer). Numata (Paragraph 32) and Nagai (Paragraphs 15, 33, and 42) recognize the common relationship between tread cap layers and tread base layers, with tread cap layers generally being harder since they are ground contacting and tread base layers generally being softer to promote, among other things, ride comfort. One of ordinary skill in the art at the time of the invention would have expected the tread cap layer of Kunisawa to be harder than the tread base layer taught by Kojima. More particularly, Nagai evidences the correlation between hardness and storage elastic modulus in a tread formed with a cap layer and a base layer, with harder rubber compositions associated with higher storage elastic modulus values (Paragraph 33). Thus, it reasons that a ratio between modulus in the cap layer and the base layer would be greater than 1 and such a general disclosure fully encompasses the claimed ratios between 1.1 and 1.7. Appellant has not provided a conclusive showing of unexpected results for the claimed ratio, it being noted that all of the inventive examples and comparative examples in Tables 1-4 of Appellant's original specification have a ratio between 1.1 and 1.7. It is emphasized that the broad range of the claims appears to be consistent with the general recognition in the tire industry that rubber compositions with higher hardness values and storage elastic modulus values are used in tread cap layers, as compared with tread base layers.
Lastly, Appellant points to multiple references that are outside those used in the pending rejection to suggest that a positive relationship is not necessarily present between hardness and storage elastic modulus. The fact that a potential composition might exist that demonstrates an inverse relationship between hardness and storage elastic modulus does not render the claims non-obvious. In the context of a tread formed with a cap layer and a base layer, it is generally recognized that rubber compositions demonstrating greater hardness and storage elastic modulus are used in tread cap layers, as compared to tread base layers. This relationship is specifically detailed by Nagai (Paragraph 33), which is directed to a tread assembly formed with a tread cap layer and a tread base layer.
In the Reply Brief filed April 4, 2025, the applicant-appellant argued in roughly one-third of the Reply Brief that the cited art taught content values of the rubber composition inside and outside of the claims, that the results were indeed unexpected in roughly half of the Reply Brief, and, in the final fraction of the Reply Brief, that the evidentiary references demonstrate that even if the rubber hardness increases, the storage elastic modulus E' of the rubber does not necessarily increase.
The PTAB reversed the examining corps in short shrift, noting that the examiner bears the initial burden, on review of the prior art or on any other ground, of presenting a prima facie case of unpatentability, citing In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992), but that when the references cited by the examiner fail to establish a prima facie case of obviousness, the rejection is improper and will be overturned, citing In re Fine, 837 F.2d 1071, 1074 (Fed. Cir. 1988). The PTAB overturned the examiner's position on Nagai, i.e., as a motivation for one of ordinary skill in the art to form a tire with the claimed storage elastic modulus values, pointing out that Nagai discloses that base rubber layers may be formed of rubber materials having storage elastic modulus lower or higher than that of the rubber material forming the cap rubber layer, citing to Nagai's ¶ [0015] versus Nagai's ¶¶ [0017] and [0046]. The PTAB noted that Nagai discloses nothing more specific concerning the ratio of the storage elastic modulus of a cap layer and a base layer, which fails to demonstrate the obviousness of the claimed ratio. Accordingly, the PTAB held that no obligation to show unexpected results for the ratio was established.
The reversed rejection in the 422 Application is typical of three patterns in the USPTO examining corps. First, without showing unpredictability or a lack of an expectation of success, a USPTO examiner can typically establish the obviousness of a composition by combining known components from many references—seemingly from an unlimited corpus of all known components in the field. Second, unexpected results can be difficult to show by examples that do not directly compare to each other, preferably on a variable-by-variable basis., and for claims that the examiner has not agreed are commensurate in scope with the data. Third, the USPTO examining corps—led by SPEs and USPTO quality control officers—has a lax approach to multi-reference inherency-like rejections, despite the law of the Federal Circuit. The case law on point for inherency, traditionally based on a single reference, and and more frequently closer to novelty questions, in the guidance to USPTO examiner's is found in MPEP § 2112(IV), i.e.,
“[i]n relying upon the theory of inherency, the examiner must provide a basis in fact and/or technical reasoning to reasonably support the determination that the allegedly inherent characteristic necessarily flows from the teachings of the applied prior art.” Ex parte Levy, 17 USPQ2d 1461, 1464 (Bd. Pat. App. & Inter. 1990) (emphasis in original). In PAR Pharmaceutical, Inc. v. TWI Pharmaceuticals, Inc., 773 F.3d 1186, 112 USPQ2d 1945 (Fed. Cir. 2014) … . The Federal Circuit stated that while “inherency may support a missing claim limitation in an obviousness analysis”, “the use of inherency, a doctrine originally rooted in anticipation, must be carefully circumscribed in the context of obviousness.” Id. at 1194-95, 112 USPQ2d at 1952.
In cases where the applicant can objectively prove that inherency is not present, either by experimental evidence or technical or patent literature, there may be a better chance that the inherency of a claim to a novel composition—not exemplified in a single prior art reference—can be overcome at the PTAB, relative to arguing before an examiner.
Footnotes
1. For reference, Numata's ¶ [0032] describes (emphasis added by the author) that “[i]n contrast, from the viewpoint of decreasing the rolling resistance, a low heat generating rubber having a loss tangent (tan δa) of 0.035 to 0.055 is preferably used in the base rubber layer 2Ga since the energy loss is small. The rubber hardness (Hsa) of the base rubber layer 2Ga is lower than the rubber hardness (Hsb) of the cap rubber layer 2Gb. From the viewpoint of obtaining a necessary steering stability, it is preferable to use a rubber having a hardness of 62 to 66 in the base rubber layer 2Ga.”
2. For reference, Nagai's ¶ [0015] describes that “[o]ther characteristic of the present invention is summarized in that the tread portion includes two layers of a base rubber layer and a cap rubber layer, the base rubber layer being placed on an inner side in a tire radial direction, the cap rubber layer being placed on an outer side in the tire radial direction, the base rubber layer is formed of a rubber material having a storage elastic modulus lower than that of a rubber material forming the cap rubber layer, and a thickness of the base rubber layer is set smaller on the outer side in the tire width direction than on the inner side in the tire width direction.”
3. For reference, Nagai's ¶ [0033] describes that “[a] material forming the base rubber layer 10 and a material forming the cap rubber layer 11 are different from each other in their storage elastic modulus. In the present embodiment, the base rubber layer 10 is formed of a rubber material having a storage elastic modulus lower than that of a rubber material forming the cap rubber layer 11. The high and low of the storage elastic modulus at 30 degrees centigrade represent so-called “hardness” and “softness” of the rubber; a rubber with a high storage elastic modulus is “hard,” whereas a rubber with a low storage elastic modulus is “soft.” Accordingly, in the present embodiment, the base rubber layer 10 is formed of a soft rubber material, and the cap rubber layer 11 is formed of a hard rubber material.”
4. For reference, Nagai's ¶ [0042] describes that “[i]n the present embodiment, the base rubber layer 10 is formed of a rubber material having a storage elastic modulus lower than that of a rubber material forming the cap rubber layer 11, and the thicknesses t1 and t2 of the base rubber layer 10 are set such that the thickness on the outer side in the tire width direction is small and the thickness on the inner side in the tire width direction is large. In this manner, since the cap rubber layer 11 comes in contact with the road, forming the cap rubber layer 11 with a hard rubber material directly contributes to improvement in the steering stability. Furthermore, since the base rubber layer 10 transmits input of dips and bumps of the road and ground reaction force to the tire casing, and eventually to the shaft, forming the base rubber layer 10 with a soft rubber material is effective in improving the comfortability.”
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