Rust Oleum Corp v. Stuart Alan

1. Case Identification

• Case #: IPR2017-02158
• Patent #: 6,669,991
• Filed: September 22, 2017
• Petitioner(s): Rust-Oleum Corporation and RPM International, Inc.
• Patent Owner(s): Alan Stuart, Trustee for the Cecil G. Stuart and Donna M. Stuart Revocable Living Trust Agreement and CDS Development LLC
• Challenged Claims: 1-11, 13-14, 20-24

2. Patent Overview

• Title: Method and Composition for Rejuvenating Weathered Polymeric Materials
• Brief Description: The ’991 patent discloses compositions and methods for rejuvenating weathered vinyl resins, such as vinyl siding. The invention involves applying a composition containing at least 50% by weight of one or more organic solvents that have a "solubility parameter" within a specified range to remove chalking and restore the surface's original color, luster, and gloss.

3. Grounds for Unpatentability

Ground 1: Anticipation by Baumgärtel - Claims 1-11, 13-14, and 20-24 are anticipated by Baumgärtel.

• Prior Art Relied Upon: Baumgärtel (German Patent Application DE 28 08 005).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Baumgärtel taught a method for regenerating and restoring weathered thermoplastic resin surfaces, including poly(vinylchloride) (PVC) siding, to make them appear new. Baumgärtel’s Example 1 described rubbing weathered PVC siding with a composition of 99 wt% dichloromethane. Petitioner asserted that this solvent inherently possessed a solubility parameter (Hildebrand 9.7 (cal/cm³)^1/2; Hansen 9.9) that fell within the ranges of all challenged claims. Baumgärtel also taught that dichloromethane could be partially replaced with acetone, another solvent within the claimed ranges, and disclosed applying the composition with "cellulose towels," which Petitioner argued anticipated the "cloth or sponge" limitation of claim 11.
  • Key Aspects: The central argument was that the claimed solubility parameter was an inherent, unstated property of the solvents disclosed in Baumgärtel for the identical purpose of rejuvenating PVC siding. Therefore, Baumgärtel was argued to anticipate the claims even without explicitly mentioning the term "solubility parameter."

Ground 2: Obviousness over Baumgärtel and Billmeyer - Claims 1-11, 13-14, and 20-24 are obvious over Baumgärtel in view of Billmeyer.

• Prior Art Relied Upon: Baumgärtel (German Patent Application DE 28 08 005) and Billmeyer (Textbook of Polymer Science, Third Edition).
• Core Argument for this Ground:
  • Prior Art Mapping: Presented as an alternative to anticipation, this ground asserted that Baumgärtel taught all claimed elements except for an explicit instruction to select solvents based on a specific solubility parameter range. Billmeyer, a standard polymer science textbook, was argued to supply this by teaching the use of solubility parameters (both Hildebrand and Hansen) to select solvents capable of swelling, but not dissolving, polymers like PVC. Billmeyer disclosed that solvents with a solubility parameter within about 1.7-2.0 (cal/cm³)^1/2 of PVC's own parameter (9.5) would be effective, a range that fully encompassed the claimed ranges.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA), knowing from Baumgärtel the need to use a solvent that swells PVC for rejuvenation, would combine its teachings with a standard reference like Billmeyer to identify or optimize such solvents. Billmeyer provided the known scientific principle—using solubility parameters—to achieve the exact goal described in Baumgärtel.
  • Expectation of Success: A POSITA would have a high expectation of success because the combination involved applying a well-established principle (solubility parameters from Billmeyer) to a known problem and composition (rejuvenating PVC siding with solvents from Baumgärtel).

Ground 3: Anticipation by Gladstone - Claims 1-10, 13, and 20 are anticipated by Gladstone.

• Prior Art Relied Upon: Gladstone (“Tarred 'N' Bothered,” a Chicago Tribune article from February 18, 2000).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Gladstone, a newspaper column, taught applying acetone to weathered vinyl siding to remove "chalking" and expose the "original luster," creating a "slight shine or gloss." This was asserted to be a direct teaching of the claimed method of rejuvenating vinyl siding. As in the Baumgärtel ground, Petitioner argued the solubility parameter of acetone (Hildebrand 9.9, Hansen 9.8 (cal/cm³)^1/2) was an inherent property that fell squarely within the claimed ranges.
  • Key Aspects: Petitioner bolstered this argument by citing the Patent Owner's own infringement contentions from co-pending litigation, in which the Patent Owner allegedly admitted that a 75-100% acetone formulation met every limitation of the challenged claims.

• Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 11 over Gladstone, arguing the use of a cloth or sponge to apply acetone was a predictable and common-sense variation.

4. Key Claim Construction Positions

• "Rejuvenating [and Cleaning] the Surface of Vinyl Siding": Petitioner argued this preamble was limiting because the applicant relied on it during prosecution to distinguish prior art. The proposed construction, based on the patent's specification, was "to remove or transform the chalky surface... and restore the color, luster, and/or gloss."
• "Solubility parameter": Petitioner argued the claims were indefinite because the specification disclosed two different measures (Hildebrand and Hansen) without specifying which to use. For the IPR, Petitioner proposed the broadest reasonable interpretation: a parameter measured by any of the disclosed methods, including both Hildebrand and Hansen solubility parameters. The Petitioner noted that for the solvents disclosed in the prior art, the values under both measures fell within the claimed ranges.
• "About": Petitioner proposed construing "about" to mean a range of ±0.1 from the recited value (e.g., "about 8.0" means 7.9 to 8.1). This was argued to be consistent with the decimal precision used throughout the claims and standard scientific convention, and that a broader construction would improperly cause dependent claim ranges to overlap.

5. Relief Requested

• Petitioner requested institution of inter partes review and cancellation of claims 1-11, 13-14, and 20-24 of Patent 6,669,991 as unpatentable.