PTAB

IPR2017-01353

New NGC Inc v. United States Gypsum Co

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Set Gypsum-Containing Products
  • Brief Description: The ’904 patent discloses methods for preparing set gypsum-containing products, such as gypsum boards, with increased strength and resistance to permanent deformation (sag). The claimed method involves forming a mixture of calcined gypsum, water, an accelerator, and one or more specified "enhancing materials," which are primarily condensed phosphates like sodium trimetaphosphate (STMP).

3. Grounds for Unpatentability

Ground 1: Obviousness over Graux Combination - Claims 1-4, 6, 8, 11-13, 15, and 18 are obvious over Graux in view of ASTM C473-95, Hjelmeland, Sucech, and Kincade.

  • Prior Art Relied Upon: Graux (Patent 5,932,001), ASTM C473-95 (an industry standard), Hjelmeland (Patent 5,980,628), Sucech (Patent 5,643,510), and Kincade (Patent 3,573,947).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Graux teaches the core claimed composition, disclosing a plaster product made by mixing calcined gypsum, water, additives including accelerators, and a starch "crosslinked with sodium trimetaphosphate" (STMP), which is a claimed enhancing material. Petitioner asserted that ASTM C473-95, a standard testing method repeatedly identified in the ’904 patent itself, supplies the claimed sag resistance measurement limitation. For dependent claims, Hjelmeland was cited for teaching the use of phosphates within the claimed concentration ranges, Kincade for teaching a heat-resistant accelerator (HRA) (claim 8), Sucech for teaching the use of foaming agents to create uniform voids (claims 15, 18), and Graux itself for disclosing pregelatinized starch (claims 11-13).
    • Motivation to Combine: A POSITA would combine the teachings of Graux with the other references to optimize a known gypsum formulation. It would have been obvious to use the industry-standard ASTM test to verify the sag resistance of the Graux composition. A POSITA would also be motivated to incorporate known additives from Kincade (for heat resistance), Sucech (for lower density), and Hjelmeland (for concentration ranges) to achieve their predictable benefits in the base Graux formulation.
    • Expectation of Success: Petitioner contended a POSITA would have had a high expectation of success because all references operate in the same field of gypsum products, address well-known industry problems, and propose chemically compatible and predictable solutions.

Ground 2: Obviousness over Satterthwaite Combination - Claims 1-4, 6, 8, 11-13, 15, and 18 are obvious over Satterthwaite in view of ASTM C473-95, Hjelmeland, Sucech, and Kincade.

  • Prior Art Relied Upon: Satterthwaite (Patent 3,234,037), ASTM C473-95, Hjelmeland (Patent 5,980,628), Sucech (Patent 5,643,510), and Kincade (Patent 3,573,947).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative primary reference, Satterthwaite, which disclosed manufacturing acoustical ceiling tiles from a mixture of water and gypsum. Critically, Satterthwaite taught treating a starch binder with STMP for the express purpose of creating a finished tile with "increased resistance to warp or sag." Petitioner asserted this established the core inventive concept. The secondary references were mapped identically to Ground 1: ASTM provided the sag measurement, Hjelmeland the concentration ranges, Kincade the HRA, and Sucech the foaming agent. Petitioner argued that Satterthwaite's disclosure of "gelatinization" also rendered the pregelatinized starch limitations obvious.
    • Motivation to Combine: A POSITA, starting with Satterthwaite's teaching of using STMP to improve sag resistance, would be motivated to add other conventional components to create a finished product. This would include adding an accelerator (taught by Kincade and admitted prior art) to control set time and improve strength, and testing the final product using the standard ASTM protocol. The motivations to add foaming agents from Sucech and to optimize phosphate concentrations based on Hjelmeland were the same as in Ground 1.
    • Expectation of Success: Petitioner argued for a high expectation of success, as Satterthwaite directly links the use of STMP to the desired outcome of sag resistance, and combining it with other well-known, compatible additives and testing methods from the same field would yield only predictable results.

4. Key Claim Construction Positions

  • "Accelerator": Petitioner argued this term should be construed broadly as any "reagent or combination of reagents known to be useful to influence the rate of formation of set gypsum." This construction was based on a related patent and would encompass the heat-resistant accelerators disclosed in the prior art like Kincade.
  • "Enhancing Material(s)": Petitioner proposed construing this term as an "additive that improves at least one of resistance to permanent deformation, strength, and dimensional stability." This construction is central to the obviousness argument, as it aligns the function of the claimed materials with the explicit purpose of adding phosphates like STMP in prior art references such as Satterthwaite.
  • "Set Gypsum-Containing Product": Petitioner argued this term should mean any "product containing calcium sulfate dihydrate," including boards, plasters, and tiles, based on the patent's specification. This ensures that prior art disclosing various types of gypsum products (e.g., tiles in Satterthwaite) is applicable.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-4, 6, 8, 11-13, 15, and 18 of the ’904 patent as unpatentable under 35 U.S.C. §103.