PTAB

IPR2025-01459

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

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Key Events
Petition
petition

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" at the point-of-use. The claimed solution is generated from 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 expressly discloses compositions and methods for producing non-equilibrium peracetic acid (PAA) solutions. It was asserted that Buschmann 1 teaches mixing alkaline hydrogen peroxide with triacetin to produce an alkaline mixture containing non-equilibrium PAA, hydrogen peroxide, triacetin, and glycerol (another name for the claimed 1,2,3-propanetriol). Petitioner further contended that Buschmann 1 discloses using water as a solvent and sodium hydroxide as a base, thereby teaching every component of the solution required by independent claim 1. For dependent claim 2, Petitioner argued that Buschmann 1’s disclosure of producing PAA at a pH "greater than about 10" and its exemplary pH of 12.0 anticipates or renders obvious the claimed pH range of "about 11.2 to about 13.37."
    • Motivation to Combine (for §103 grounds): The obviousness argument was presented as an alternative. Petitioner argued a person of ordinary skill in the art (POSITA) would have been motivated to optimize the pH disclosed in Buschmann 1 to enhance PAA formation while minimizing a known self-decomposition reaction that occurs at a lower alkaline pH (7.5-10.5).
    • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success in optimizing the pH, as pH is a known result-effective variable for PAA stability and formation.

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, which concerns the production of peroxy acids, discloses compositions that contain nearly all components of claim 1. Specifically, Example V of Montgomery allegedly discloses a mixture containing glycerin (1,2,3-propanetriol), water, hydrogen peroxide, and glyceryl triacetate (triacetin) that produces peroxyacetic acid. The only missing element is an alkali metal hydroxide, as Montgomery's Example V uses ammonium hydroxide.
    • Motivation to Combine (for §103 grounds): Petitioner argued a POSITA would combine the teachings because Montgomery explicitly teaches that suitable buffers for the reaction include sodium hydroxide and potassium hydroxide, which are alkali metal hydroxides, and lists them as equivalents to ammonium hydroxide. Therefore, substituting the disclosed sodium hydroxide for the ammonium hydroxide in Example V would have been an obvious and simple substitution to a POSITA.
    • Expectation of Success (for §103 grounds): A POSITA would expect success because Montgomery teaches that alkali metal hydroxides are suitable buffers for the reaction, indicating they are known to be compatible and effective.

Ground 3: Obviousness over Okano 1 and Okano 2 - Claims 1-3 are obvious over Okano 1 in view of 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 teach sterilizer compositions made from reacting triacetin with hydrogen peroxide in water, in the presence of an alkaline pH adjusting agent like sodium hydroxide, to form peracetic acid. Petitioner contended that the combination explicitly teaches all components of the solution in claim 1. For claim 2 (pH range) and claim 3 (concentration range), Petitioner asserted that both references disclose overlapping ranges. Okano 1 and Okano 2 both teach a pH range of 8-12, which overlaps the claimed range. Similarly, both references disclose peracetic acid concentrations that fall within or overlap the claimed range of 1% to 7.1%.
    • Motivation to Combine (for §103 grounds): Petitioner argued a POSITA would combine Okano 1 and Okano 2 because both references address the same problem—creating effective, non-chlorine-based sterilizers—using the exact same core components (triacetin, hydrogen peroxide, water, sodium hydroxide). Combining their teachings would have been a matter of pursuing a known approach to a known problem.
    • Expectation of Success (for §103 grounds): A POSITA would have a reasonable expectation of success because the components and reaction conditions described in both references are highly similar and compatible.

  • Additional Grounds: Petitioner asserted additional anticipation and obviousness challenges against claims 1-3 based on Buschmann 2 (Application # 2009/314652), Okano 1 alone, and Okano 2 alone. These grounds relied on similar arguments regarding the disclosure of all claimed chemical components and overlapping pH and concentration ranges.

4. Key Claim Construction Positions

  • "non-equilibrium solution of peracetic acid": Petitioner argued this phrase, which is not clearly defined in the specification, should be given its plain and ordinary meaning. For the purposes of the IPR, Petitioner proposed construing it as "a solution of peracetic acid that is not at equilibrium under a given set of conditions, because the concentrations of the components, including peracetic acid, are changing over time, and/or because the reaction is irreversible." This construction is central to grounds where the prior art describes an irreversible reaction, which Petitioner equated with a non-equilibrium state.

5. Key Technical Contentions (Beyond Claim Construction)

  • Inherent Presence of 1,2,3-propanetriol: A central technical argument across multiple grounds was that 1,2,3-propanetriol (glycerol) is an inherent and necessary by-product of the perhydrolysis reaction between triacetin and hydrogen peroxide. Petitioner argued that even when a prior art reference did not explicitly name 1,2,3-propanetriol as a component, a POSITA would have immediately recognized its presence in the resulting solution, thereby satisfying that claim limitation. Petitioner noted that the patent owner did not challenge this interpretation during prosecution.

6. Relief Requested

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