PTAB

IPR2025-01459

Clean Chemistry, Inc. v. Enviro Tech Chemical Services, Inc.

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1. Case Identification

2. Patent Overview

  • Title: Methods and Compositions for the Generation of Peracetic Acid on Site at the Point-of-Use
  • Brief Description: The ’443 patent describes methods for generating a "non-equilibrium solution of peracetic acid" for use as a disinfectant. The solution is formed on-site by reacting aqueous hydrogen peroxide, triacetin, water, and an aqueous source of an alkali metal or earth alkali metal hydroxide.

3. Grounds for Unpatentability

Ground 1: Anticipation and Obviousness over Buschmann 1 - Claims 1-2 are anticipated by and/or obvious over Buschmann 1.

  • Prior Art Relied Upon: Buschmann 1 (Application # 2009/175956).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Buschmann 1 anticipates claim 1 by disclosing the on-site production of an alkaline mixture of "non-equilibrium" peracetic acid (PAA). This mixture explicitly contains all components recited in claim 1: PAA, hydrogen peroxide, triacetin, glycerol (the chemical equivalent of claimed 1,2,3-propanetriol), water as a solvent, and a hydroxide base (sodium hydroxide). For dependent claim 2, Petitioner asserted that Buschmann 1 anticipates by disclosing an exemplary pH of 12.0, which falls within the claimed range of "about 11.2 to about 13.37."
    • Motivation to Combine (for §103 grounds): In an alternative obviousness argument for claim 2, Petitioner contended that pH is a result-effective variable. A person of ordinary skill in the art (POSITA) would be motivated to optimize the pH to be above 10.5 to maximize PAA formation while minimizing the known self-decomposition that occurs at lower alkaline pH values, making the claimed range an obvious optimization.
    • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success in adjusting the pH for optimization, as controlling pH is a routine and predictable technique in aqueous chemistry.

Ground 2: Obviousness over Montgomery - Claim 1 is obvious over Montgomery.

  • Prior Art Relied Upon: Montgomery (Patent 6,221,341).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Montgomery's Example V explicitly discloses a composition that generates peracetic acid and contains nearly all claimed components: glycerin (1,2,3-propanetriol), water, hydrogen peroxide, and triacetin. The only component not explicitly present in the example composition is an alkali metal hydroxide; Montgomery's example uses ammonium hydroxide as a buffer.
    • Motivation to Combine: The core of the argument was obvious substitution. Petitioner argued a POSITA would be motivated to substitute an alkali metal hydroxide for the ammonium hydroxide because Montgomery expressly teaches that "suitable buffers include sodium hydroxide, potassium hydroxide, [and] ammonium hydroxide," presenting them as known, interchangeable equivalents for controlling pH in the reaction.
    • Expectation of Success: A POSITA would have a high expectation of successfully making this substitution, as Montgomery teaches the components are equivalent for the intended purpose of buffering the solution to facilitate peroxyacetic acid formation.

Ground 3: Obviousness over Okano 1 and Okano 2 - Claims 1-3 are obvious over the combination of Okano 1 and Okano 2.

  • Prior Art Relied Upon: Okano 1 (Patent 7,919,122) and Okano 2 (JP 2006-045147 A).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that both Okano 1 and Okano 2 disclose making aqueous, non-equilibrium sterilizing solutions of peracetic acid from the same core components recited in claim 1: triacetin, hydrogen peroxide, water, and sodium hydroxide. The presence of the reaction byproduct 1,2,3-propanetriol was argued to be inherent in both references. For dependent claims 2 and 3, Petitioner argued the overlapping pH ranges (8-12 in both references) and peracetic acid concentration ranges (up to 2.7 wt% in Okano 1; up to 2 wt% in Okano 2) create a presumption of obviousness for the claimed ranges.
    • Motivation to Combine: A POSITA would combine Okano 1 and Okano 2 because both references address the identical problem of creating effective, non-chlorine-based sterilizers and employ the same fundamental chemical reaction (reacting triacetin with hydrogen peroxide in an alkaline aqueous solution) as the solution.
    • Expectation of Success: A POSITA would have a high expectation of success in combining their teachings, as the references use the same core components and reaction principles to achieve the same established goal.

  • Additional Grounds: Petitioner asserted additional anticipation and obviousness challenges based on Buschmann 2 alone, Okano 1 alone, and Okano 2 alone, relying on similar chemical principles and arguments of inherency and routine optimization.

4. Key Claim Construction Positions

  • "Non-equilibrium solution of peracetic acid": Petitioner argued this term should be construed to mean a solution that is not at equilibrium, either because the concentrations of its components are changing over time or because the reaction that forms the peracetic acid is irreversible. This construction was central to Petitioner's arguments, as prior art references describing irreversible PAA formation reactions (such as in Okano 1) would meet this critical claim limitation.

5. Key Technical Contentions (Beyond Claim Construction)

  • Inherent Formation of 1,2,3-Propanetriol: A central technical contention across multiple grounds was that 1,2,3-propanetriol (also known as glycerin or glycerol) is an inherent and necessary byproduct of the perhydrolysis reaction between triacetin and hydrogen peroxide. Petitioner argued that any prior art disclosing this core reaction therefore inherently discloses the presence of 1,2,3-propanetriol, satisfying that claim element even if the compound is not explicitly named in the reference.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-3 of the ’443 patent as unpatentable.