PTAB

IPR2020-00768

Solvay USA Inc v. World Source Enterprises LLC

Log In
Key Events
Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Liquid Formulations of Urease Inhibitors for Fertilizers
  • Brief Description: The ’231 patent relates to liquid solvent formulations for the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT), which is used in fertilizers. The patent’s alleged invention centers on replacing potentially toxic solvents, such as N-methyl pyrrolidone (NMP), with the less toxic solvent dimethyl sulfoxide (DMSO).

3. Grounds for Unpatentability

Ground 1: Obviousness over Iannotta and CN400 - Claims 1-17 are obvious over Iannotta in view of CN400.

  • Prior Art Relied Upon: Iannotta (Application # 2013/0145806) and CN400 (Chinese Patent No. 101200400 B).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Iannotta discloses liquid fertilizer additive compositions containing the urease inhibitor NBPT and various aprotic and protic solvents, but does not explicitly name DMSO. CN400, which is directed to the same field of controlled-release urea fertilizers, expressly teaches using NBPT as a urease inhibitor and DMSO as a suitable organic solvent for dissolving it. Petitioner asserted that the combination of Iannotta and CN400 teaches all limitations of the challenged claims. For instance, claim 1 requires a liquid fertilizer additive with a urease inhibitor (NBPT) and an aprotic solvent from a group including DMSO. Iannotta provided the base composition, and CN400 provided the specific teaching of DMSO in that context. Dependent claims reciting additional co-solvents (e.g., propylene carbonate, glycerine) and additives (e.g., surfactants, dyes) were argued to be disclosed in Iannotta and/or CN400.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to develop an improved solvent system for NBPT. Iannotta taught the desirability of a solvent system with a "favorable toxicological and/or ecological profile." Petitioner contended that at the time of the invention, DMSO was widely known as a preeminent, commercially available, and low-toxicity solvent particularly suited for agrochemical applications and for dissolving NBPT. A POSITA seeking to improve upon Iannotta's system would have been motivated to look to analogous art like CN400, which explicitly identified the low-toxicity DMSO as an effective solvent for NBPT. The combination amounted to a simple substitution of one known solvent for another to achieve predictable results.
    • Expectation of Success: A POSITA would have had a high expectation of success. The art, including commercial product literature, established that DMSO was one of a small, finite number of recommended solvents for NBPT. Therefore, substituting or adding DMSO into the solvent systems of Iannotta would have been expected to successfully dissolve the NBPT and yield a stable, effective fertilizer additive.

Ground 2: Obviousness over Kolc and CN400 - Claims 1-17 are obvious over Kolc in view of CN400.

  • Prior Art Relied Upon: Kolc (Patent 4,530,714) and CN400 (Chinese Patent No. 101200400 B).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kolc is a foundational patent teaching urease-inhibited fertilizer compositions containing NBPT and discloses the use of various "suitable organic solvents" to prepare liquid formulations. While Kolc did not explicitly propose DMSO for the final product, it disclosed using deuterated DMSO to dissolve NBPT for NMR analysis, which Petitioner argued would have informed a POSITA of DMSO's high solubility for NBPT. As in Ground 1, CN400 provided the explicit teaching of using DMSO as the organic solvent for NBPT in a fertilizer composition. The combination of Kolc’s foundational teachings on NBPT formulations and CN400’s specific solvent disclosure was alleged to render the claims obvious.
    • Motivation to Combine: The motivation was similar to Ground 1. A POSITA starting with Kolc's teachings would have sought to formulate NBPT in a commercially viable, low-toxicity solvent system. Given the extensive knowledge in the art about DMSO's efficacy and safety profile for agrochemicals, and its known ability to dissolve NBPT (as suggested in Kolc itself), a POSITA would have been directed to consider references like CN400. CN400 confirmed that DMSO was a suitable choice for a fertilizer composition, providing a clear motivation to incorporate it into a system based on Kolc.
    • Expectation of Success: Success would have been highly probable and predictable. The combination merely involved applying a well-known, effective solvent (DMSO) to a known composition (Kolc's NBPT fertilizer). This was presented as a routine design choice from a finite number of known, predictable solvent options, not an inventive step.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-17 of the ’231 patent as unpatentable under 35 U.S.C. §103.