Organik Kimya San Ve Tic As v. Rohm Haas Co

1. Case Identification

• Case #: IPR2014-00185
• Patent #: 6,020,435
• Filed: November 21, 2013
• Petitioner(s): Organik Kimya AS
• Patent Owner(s): Rohm and Haas Company
• Challenged Claims: 1-5

2. Patent Overview

• Title: Process For Preparing Multi-Stage Emulsion Polymers
• Brief Description: The ’435 patent relates to a process for preparing multi-stage emulsion polymers, such as those used in paints and paper coatings. The asserted invention involves swelling a core-shell polymer using a swelling agent in the presence of an added monomer, specifically under conditions where there is no substantial polymerization of that monomer.

3. Grounds for Unpatentability

Ground 1: Anticipation by Toda - Claims 1-5 are anticipated under 35 U.S.C. § 102 by Toda.

• Prior Art Relied Upon: Toda (Patent 5,360,827).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Toda, particularly its Example 9, discloses every element of the challenged claims. Toda describes a process for preparing hollow polymer particles that includes synthesizing a multi-stage polymer with a core, intermediate, and shell layer. After polymerization of the shell stage is complete (evidenced by a 98% conversion rate), Toda teaches lowering the reaction temperature, adding styrene monomer to soften the particles, and then adding a swelling agent (potassium hydroxide). Petitioner contended that performing the swelling step after polymerization is complete and the temperature is lowered inherently creates the claimed "conditions wherein there is no substantial polymerization of the monomer," thus anticipating all limitations of claim 1 and its dependent claims.

Ground 2: Obviousness over Touda - Claims 1-5 are obvious under 35 U.S.C. § 103 over Touda.

• Prior Art Relied Upon: Touda (Patent 5,077,320).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Touda discloses a process for making microvoid-containing polymers by swelling particles with a base in the presence of an organic solvent. While Touda's Example 1 uses toluene (a non-polymerizable solvent), the specification explicitly teaches that a polymerizable organic solvent, such as styrene, may be used instead. Petitioner argued that Touda's process, when modified with this express teaching, discloses all limitations. Specifically, the swelling step in Touda's Example 1 occurs after polymerization is substantially complete (97% conversion after eight hours), thereby meeting the "no substantial polymerization" condition.
  • Motivation to Combine (for §103 grounds): This ground relies on a modification rather than a combination. Petitioner argued a person of ordinary skill in the art (POSITA) would be motivated to substitute styrene for toluene in Touda's Example 1 because Touda itself suggests the interchangeability. Touda teaches that styrene is a suitable polymerizable organic solvent, and a POSITA would expect predictable results from this substitution due to the similar physical properties and solubility profiles of styrene and toluene.
  • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success, as this was a simple substitution of one known solvent for another, explicitly suggested by the prior art reference itself.

Ground 3: Obviousness over Okubo and Touda - Claims 1-5 are obvious over Okubo in view of Touda.

• Prior Art Relied Upon: Okubo (Patent 4,910,229) and Touda (Patent 5,077,320).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Okubo discloses a process for preparing multi-stage hollow polymer particles, including core and shell layers. In Okubo's Example 1, a swelling step is performed after the shell layer polymerization is complete (98.9% conversion after 13 hours), thus satisfying the "no substantial polymerization" condition. However, Okubo achieves particle softening to facilitate swelling by increasing the reaction temperature, not by adding monomer. Petitioner asserted that Touda supplies this missing element by teaching the use of a polymerizable monomer (as an organic solvent) specifically to soften polymer particles at lower temperatures.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Okubo's base process with Touda's teaching to address a known need. Okubo recognized the desirability of softening polymer particles to enhance base diffusion and swelling. Touda provided a known and advantageous solution to achieve this softening—adding a monomer like styrene—which avoids the need for elevated temperatures that could limit the types of polymers used.
  • Expectation of Success (for §103 grounds): A POSITA would have reasonably expected success in applying Touda's known softening technique to Okubo's established polymer swelling process to achieve the recognized benefit of improved swelling at lower temperatures.

4. Key Claim Construction Positions

• Petitioner argued that the key claim term "under conditions wherein there is no substantial polymerization of the monomer" is likely indefinite because the patent provides no quantitative way to measure it.
• However, for the purposes of the inter partes review (IPR) under the broadest reasonable interpretation standard, Petitioner contended the term must at least include the four methods the ’435 patent explicitly discloses for achieving the condition: (1) adding polymerization inhibitors, (2) adding reducing agents, (3) waiting a sufficient period for free radicals to terminate (i.e., allowing polymerization to complete), or (4) cooling the reactor. This construction was critical to Petitioner's arguments, as the prior art references often achieved the condition by allowing polymerization reactions to run to completion before the swelling step.

5. Relief Requested

• Petitioner requested the institution of an IPR and the cancellation of claims 1-5 of the ’435 patent as unpatentable.