PTAB

IPR2018-00993

Daikin Industries Ltd v. Chemours Co FC LLC

Log In
Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: High Melt Flow Fluoropolymer
  • Brief Description: The ’431 patent relates to a high-melt-flow fluoropolymer, specifically a partially-crystalline copolymer of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), for use in insulating communication cables. The invention is defined by a specific combination of four properties: a hexafluoropropylene index (HFPI), low alkali metal ion content, a high melt flow rate (MFR), and a low number of unstable endgroups, intended to provide high-quality wire insulation at high extrusion speeds.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1, 2, and 5-7 over Hiraga

  • Prior Art Relied Upon: Hiraga (Japanese Application # 2002-249585).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hiraga’s Comparative Example 1 discloses a copolymer that meets every limitation of the challenged claims. Specifically, the example teaches a TFE/HFP/PPVE copolymer with a calculated HFPI of 5.2 (within the claimed 2.8-5.3 range), a potassium concentration of 15 ppm (below the <50 ppm limit of claim 1 and the <25 ppm limit of claim 2), a final MFR of 30.0 g/10 min (within the claimed 30±3 range), and 0 unstable endgroups (below the <50 limit). Petitioner contended that dependent claims specifying potassium (claim 5) and narrower MFR and endgroup ranges (claims 6 and 7) were also fully disclosed by this single example.

Ground 2: Anticipation and/or Obviousness of Claims 1-7 over Kono

  • Prior Art Relied Upon: Kono (Patent 6,743,508).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted Kono’s examples of FEP-copolymers for high-speed wire extrusion anticipate or render obvious the claims. Kono’s Comparative Example 3 allegedly discloses a copolymer with an HFPI of 4.1, an MFR of 28.3 g/10 min, and exactly 50 unstable endgroups. Kono’s Example 2 was also cited with an MFR of 32.5 g/10 min and 58 unstable endgroups, which Petitioner argued meets the "about 50" limitation under a proper construction. Petitioner further argued that since Kono discloses using non-alkali metal initiators (DHP or APS) and no stabilization process requiring such metals, the limitation of less than 50 ppm alkali metal ion is inherently met.
    • Motivation to Combine (for §103 grounds): For any limitation deemed not explicitly met, Petitioner argued a POSITA would have been motivated to optimize Kono’s disclosed parameters. For instance, if Kono’s MFR of 35.1 g/10 min in Comparative Example 5 was considered just outside the claimed range, a POSITA would have been motivated by Kono’s own teachings to adjust reaction conditions to achieve the target MFR for high-speed extrusion, a matter of routine experimentation.
    • Expectation of Success: A POSITA would have a reasonable expectation of success in making such minor adjustments, as the relationship between reaction conditions and final polymer properties like MFR was well-known.

Ground 3: Obviousness of Claims 1-7 over Kaulbach

  • Prior Art Relied Upon: Kaulbach (Patent 6,541,588).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kaulbach's Sample A11, describing an FEP-copolymer for wire coating, renders the claims obvious. Sample A11 discloses a copolymer with an HFPI of 4.1 and 28 unstable endgroups. Kaulbach explicitly teaches an “alkali metal salt-free recipe,” thus meeting the low alkali metal limitation. While Sample A11’s MFR is 24 g/10 min, outside the claimed range of 27-33 g/10 min, Petitioner contended it would have been obvious to modify this parameter.
    • Motivation to Combine: A POSITA would be motivated to increase the MFR of Kaulbach's copolymer to achieve Kaulbach's stated goal of creating a material that can be processed at higher speeds. The art, including Kono, taught that higher MFRs were preferred for high-speed extrusion, establishing a clear motivation for this routine optimization.
    • Expectation of Success: Because methods to adjust MFR were well-known and their effects predictable, a POSITA would have a high expectation of success in modifying Kaulbach’s process to produce a copolymer with an MFR within the claimed range.
  • Additional Grounds: Petitioner asserted that claims 3 and 4 (requiring <10 ppm and <5 ppm alkali metal ion, respectively) are obvious over Hiraga in view of Kaulbach’s teaching to avoid all alkali metals to improve processability. An additional ground argued claims 1-7 are obvious over Hiraga alone by substituting Hiraga's stabilization method with fluorination.

4. Key Claim Construction Positions

  • "about 30±3 g/10 min": Petitioner proposed this term be construed as "greater than 26 g/10 min and less than 34 g/10 min." This construction was based on the patent’s specification, which describes copolymers with an MFR of 26 g/10 min (Example E) and 35 g/10 min (Example F) as yielding "inadequate quality" insulation. Petitioner argued the claim term must be construed to exclude these explicitly disclosed unacceptable results.
  • "about 50 unstable endgroups": Petitioner proposed this term be construed as "approximately 50 unstable endgroups." The argument was that the patent ascribes no criticality or special meaning to the number 50 and provides no guidance on the scope of "about," so the term should be given its ordinary meaning.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-7 of the ’431 patent as unpatentable.