AMCOL Intl Corp v. Oil Dri Corp Of America

1. Case Identification

• Case #: IPR2022-00206
• Patent #: 9,439,393
• Filed: November 24, 2021
• Petitioner(s): AMCOL International Corp.
• Patent Owner(s): Oil-Dri Corporation of America
• Challenged Claims: 1-5, 8, 10-14, and 16

2. Patent Overview

• Title: Lightweight Clumping Animal Litter
• Brief Description: The ’393 patent discloses lightweight, clumping animal litter compositions comprising sodium bentonite clay and cellulose-containing filler materials. The purported innovation is achieving clumping properties substantially similar to heavier, all-bentonite litters by defining the composition based on the relative "total external surface area" of its components, rather than solely by weight.

3. Grounds for Unpatentability

Ground 1: Anticipation by House - Claims 1-5, 8, 10-14, and 16 are anticipated under 35 U.S.C. §102 by House.

• Prior Art Relied Upon: House (Patent 5,188,064).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that House, which discloses clumping cat litter compositions of sodium bentonite and cellulosic materials, anticipates every limitation of the challenged claims. The core of the argument centered on a specific composition disclosed in House’s Table II, which Petitioner designated “House-Rice” (85% Wyoming Bentonite No. 2 and 15% rice hulls). Petitioner contended that when the ’393 patent’s own complex, multi-step methodology for calculating "total external surface area" is applied to the particle size distribution and bulk density data explicitly provided in House for these components, the resulting surface area percentages for the bentonite and filler inherently fall within the ranges required by the challenged claims (e.g., ≥47% for bentonite and 5-53% for filler). Petitioner provided detailed calculations to demonstrate this result under several possible particle distribution assumptions (even, bell-curve, and upper/lower bounds) to show that House’s disclosure is inescapable.
  • Key Aspects: Petitioner asserted that House also expressly teaches that its compositions are "removably clumpable" and that the filler materials (rice hulls) are "granular," meeting other key limitations of the independent claims. Dependent claims were argued to be met by House’s disclosure of the mixture having a lower density than bentonite alone and the filler comprising grains (rice hulls).

Ground 2: Obviousness over House in view of Goss - Claims 1-5, 8, 10-14, and 16 are obvious under 35 U.S.C. §103 over House in view of Goss.

• Prior Art Relied Upon: House (Patent 5,188,064) and Goss (Patent 5,975,019).
• Core Argument for this Ground:
  • Prior Art Mapping: As an alternative to anticipation, Petitioner argued that if House were found not to disclose a sodium bentonite with a particle size distribution that meets the surface area limitations, it would have been obvious to a person of ordinary skill in the art (POSITA) to modify the “House-Rice” composition by substituting its bentonite with the FS-30 sodium bentonite disclosed in Goss. Goss discloses a different, more granular particle size distribution for its sodium bentonite. Petitioner asserted that this simple substitution would result in a composition that meets every limitation of the challenged claims.
  • Motivation to Combine: A POSITA would combine the teachings because House explicitly identifies reducing high bulk density as a key problem in the art. Goss’s FS-30 bentonite was known to have a lower bulk density than the bentonite disclosed in House. Therefore, a POSITA would have been motivated to substitute the bentonite in the House composition with the FS-30 bentonite from Goss to achieve the known goal of creating a lighter litter, a well-understood objective in the field.
  • Expectation of Success: The substitution was presented as a simple replacement of one known clumping clay for another in a standard litter formulation to optimize a predictable property (density). A POSITA would have had a reasonable expectation of success in creating a clumping litter with a lower bulk density, and calculations showed this combination would meet the specific surface area limitations of the claims.

4. Key Claim Construction Positions

• Petitioner argued that the Board should adopt the explicit definitions provided within the ’393 patent specification for several key claim terms, as these definitions are controlling.
  • “Cellulose-containing material”: A material in which 10% or more of the material is comprised of cellulose.
  • “Granular”: A solid material having a particle size below 2 mesh.
  • “Removably Clumpable”: A litter that, when wetted, forms clumps with sufficient structural integrity to withstand mechanical separation from unwetted litter for disposal.

5. Key Technical Contentions (Beyond Claim Construction)

• A central technical contention was the proper application of the ’393 patent’s nine-step methodology for calculating the "total external surface area" of litter components. Petitioner’s anticipation argument was entirely dependent on demonstrating that applying this specific, detailed calculation method—which involves sieve analysis, particle count multipliers, and bulk density adjustments—to the raw data disclosed in the House prior art patent necessarily yields compositions that fall within the claimed surface area percentage ranges.

6. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise its discretion to deny institution.
  • Fintiv Factors (§314(a)): Petitioner contended that the co-pending district court litigation was in its earliest stages, with discovery just beginning and no trial date set, weighing strongly in favor of institution.
  • Prior Art Previously Presented (§325(d)): Petitioner acknowledged that House and Goss were cited in an Information Disclosure Statement (IDS) during prosecution. However, it argued that the examiner never substantively considered, applied, or even mentioned either reference in any office action or statement of reasons for allowance. Petitioner asserted this failure to address the primary prior art references constituted a material error by the examiner, and under the Becton factors, institution is favored when relevant art was merely listed in an IDS but not evaluated on its merits.

7. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-5, 8, 10-14, and 16 of Patent 9,439,393 as unpatentable.