ISEl LLC v. PolyGuard Products Inc

1. Case Identification

• Case #: IPR2018-00428
• Patent #: 6,331,509
• Filed: January 12, 2018
• Petitioner(s): Isel., LLC
• Patent Owner(s): Polyguard Products, Inc.
• Challenged Claims: 1-2, 4-5, and 13

2. Patent Overview

• Title: Corrosion resistant lubricants, greases, and gels
• Brief Description: The ’509 patent discloses gel and grease compositions intended to provide improved corrosion resistance and performance under severe conditions. The core composition comprises a synthetic base oil, at least one polymer that is at least partially miscible with the oil, and a silica-containing material used as a thickener.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-2, 4, and 13 under §102 over Brown

• Prior Art Relied Upon: Brown (Patent 5,116,522)
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Brown, which was not before the examiner during prosecution, anticipates every limitation of claims 1-2, 4, and 13. For independent claim 1, Brown allegedly discloses a grease composition with: (1) a synthetic base oil, explicitly teaching the use of synthetic hydrocarbon oils like polyalphaolefins (PAO); (2) at least one miscible polymer, by teaching the use of “oil soluble” viscosity improvers like ethylene propylene copolymers, which are also cited in the ’509 patent; and (3) a silica-containing thickener, by explicitly stating that “silica” may be used as a thickener and dispersed in the oil until the mixture thickens. For dependent claims, Petitioner asserted Brown anticipates claim 2 by teaching silica (understood as silicon dioxide), claim 4 by teaching additives like molybdenum disulfide and graphite, and claim 13 by teaching thickeners including silica and clays.
  • Key Aspects: The core of this argument was a direct, element-by-element mapping of the claims onto the teachings of Brown, a single prior art reference that Petitioner contended was overlooked during the original examination.

Ground 2: Obviousness of Claim 5 under §103 over Brown in view of Lutz

• Prior Art Relied Upon: Brown (Patent 5,116,522) and Lutz (Patent 2,197,433)
• Core Argument for this Ground:
  • Prior Art Mapping: This ground asserted that claim 5, which adds a specific list of antioxidants to the base composition of claim 1, is obvious. Petitioner argued that Brown teaches the base composition of claim 1 and further discloses that the composition may contain "small amounts of supplemental additives" such as "oxidation inhibitors." While Brown does not name a specific inhibitor, Lutz (an art-recognized reference for stabilizing grease) explicitly teaches using diphenylamine—one of the antioxidants listed in claim 5—to dramatically increase a grease's resistance to oxidation.
  • Motivation to Combine: Petitioner contended that Brown itself provides the motivation to combine by expressly teaching the inclusion of an "oxidation inhibitor" to improve its composition. A person of ordinary skill in the art (POSITA) seeking to implement this teaching would have been motivated to consult known references like Lutz, which describes effective antioxidants for grease compositions.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the teachings. The combination involved adding a well-known and effective antioxidant (diphenylamine from Lutz) to a standard grease formulation (from Brown) for its expected purpose, which is a predictable result.

Ground 3: Anticipation of Claims 1-2 and 13 under §102 over Levy

• Prior Art Relied Upon: Levy (Patent 4,810,395)

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Levy anticipates the claims based on its own disclosures and admissions made by the Patent Owner during prosecution of a parent patent. Levy discloses grease compositions comprising: (1) a synthetic base oil (e.g., polybutene); (2) a polymer (e.g., styrene-rubber copolymers used as bleed inhibitors, which must be miscible to function); and (3) a "silica thickener" (e.g., fumed silica particles). Petitioner contended that this maps directly to claim 1.
  • Key Aspects: A central part of this argument was the prosecution history of the parent '985 patent. The examiner rejected those claims over Levy, stating Levy taught a base oil which may be synthetic, a silica thickener, and a polymeric material. In response, the applicant did not challenge this characterization but amended the claims to require a "silicate" thickener, arguing Levy "lacks any disclosure of the claimed silicate." Because the challenged ’509 patent claims broadly require "silica," not "silicate," Petitioner argued the applicant effectively admitted that Levy teaches all other elements of the claim.

• Additional Grounds: Petitioner asserted additional obviousness challenges against claim 5 based on Brown in view of Farng (Patent 5,207,939), Levy in view of Lutz, and Levy in view of Farng, all relying on similar theories of combining a base grease composition with a known antioxidant.

4. Key Claim Construction Positions

• "silica containing material" (claim 1): Petitioner argued this term should be construed broadly to mean any composition containing silicon oxide (-SiO-) groups. This construction was asserted to be consistent with the specification and the understanding of a POSITA, and is critical for mapping prior art references that disclose "silica" or "fumed silica" (silicon dioxide) to the claim limitation.
• "at least partially miscible" (claim 1): Petitioner proposed this term should be construed to mean "capable of being at least partially dissolved." This construction was based on the plain and ordinary meaning in the art, as the ’509 patent provides almost no specific definition beyond stating it is a required property for the polymer. This interpretation is key to arguing that polymers described as "soluble" or functioning as "bleed inhibitors" in the prior art inherently meet this limitation.

5. Key Technical Contentions (Beyond Claim Construction)

• Prosecution History Estoppel: Petitioner's argument relied heavily on the prosecution history of the related '985 patent. It was contended that the applicant's sole basis for distinguishing Levy during that prosecution was the difference between "silica" (disclosed by Levy) and "silicate" (the new limitation added to the '985 claims). Petitioner argued that because the challenged claims of the ’509 patent reverted to the broader term "silica," the Patent Owner's prior arguments confirm that Levy teaches all elements of the asserted claims. This contention framed the allowance of the ’509 patent as an oversight by the examiner.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-2, 4-5, and 13 of Patent 6,331,509 as unpatentable under 35 U.S.C. §102 and/or §103.