CLearWater Paper Corp v. Graphic Packaging Intl LLC

1. Case Identification

• Case #: IPR2025-00878
• Patent #: 8,637,126
• Filed: April 21, 2025
• Petitioner(s): Clearwater Paper Corporation
• Patent Owner(s): Graphic Packaging International LLC
• Challenged Claims: 1-3 and 11

2. Patent Overview

• Title: Biodegradable Laminate for Paper and Paperboard
• Brief Description: The ’126 patent describes a product, such as a paper cup, comprising a paperboard substrate with a biodegradable polyester polymer layer coated directly onto both the interior and exterior surfaces to act as moisture barriers.

3. Grounds for Unpatentability

Ground 1: Anticipation over Cleveland - Claims 1-3 and 11 are anticipated by Cleveland under 35 U.S.C. §102.

• Prior Art Relied Upon: Cleveland (Application # US 2006/0051603).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Cleveland discloses every limitation of the challenged claims. Cleveland teaches a biodegradable laminate for paper-based articles like cups, comprising a paperboard substrate with coextruded copolyester layers on both surfaces without intervening adhesive layers. This structure includes a first moisture protectant layer on the interior surface and a separate, second layer on the exterior surface, both comprising biodegradable polyester. Cleveland also explicitly discloses a coat weight range of 10 to 40 lbs./3000 ft², which overlaps the claimed range of 5 to 30 lbs./3000 ft². For dependent claims, Cleveland teaches adding fillers like calcium carbonate to the copolyester layers to reduce cost and increase the degradation rate, meeting the limitations of claims 2, 3, and 11.
  • Key Aspects: Petitioner contended that Cleveland, which was not considered during prosecution, was assigned to the same entity as the ’126 patent and shares two inventors, yet was not disclosed to the examiner.

Ground 2: Obviousness over Nakagawa and Admitted Prior Art - Claims 1-3 and 11 are obvious over Nakagawa in view of the Applicant’s Admitted Prior Art.

• Prior Art Relied Upon: Nakagawa (Japanese Patent Application Publication No. JP H6-62944) and Applicant’s Admitted Prior Art from the ’126 patent specification.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted Nakagawa discloses a biodegradable paper cup with a biodegradable polyester plastic laminated directly onto both the interior and exterior surfaces. This teaches all limitations of claim 1 except for the specific coat weight. The ’126 patent itself admits that for conventional paper cups, a coat weight of 7.2-21.6 lbs./3000 ft² was "common." Petitioner argued that Nakagawa’s failure to specify a coat weight would lead a POSITA to use a conventional, known-effective coat weight as admitted in the ’126 patent’s own background section. For the dependent claims, Nakagawa discloses mixing its biodegradable plastics with non-degradable additives, and a POSITA would have known that calcium carbonate is a common filler for this purpose.
  • Motivation to Combine: A POSITA would combine Nakagawa’s biodegradable cup with the conventional coat weights admitted in the ’126 patent to achieve the desired waterproofing performance, which was the stated goal of both the prior art and the patent. This constitutes applying a known technique (conventional coat weights) to a similar product (biodegradable cup) to yield predictable results.
  • Expectation of Success: Since the admitted prior art describes the claimed coat weight range as common for achieving waterproofing in paper cups, a POSITA would have had a high expectation of success when applying this same coat weight range to the biodegradable cup described in Nakagawa.

Ground 3: Obviousness over Nakagawa and Tanner - Claims 1-3 and 11 are obvious over Nakagawa in view of Tanner.

• Prior Art Relied Upon: Nakagawa (Japanese Patent Application Publication No. JP H6-62944) and Tanner (Patent 5,213,858).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground presented an alternative to Ground 2 for supplying the coat weight limitation. As before, Nakagawa taught a biodegradable paper cup with polyester coatings on both sides. Tanner, which also relates to biodegradable paperboard packages like cups, explicitly discloses applying a biodegradable polymer resin in a coating weight of 7 to 20 lbs./3000 ft², a range falling entirely within the ’126 patent’s claimed range.
  • Motivation to Combine: A POSITA seeking to implement Nakagawa’s biodegradable cup would look to analogous art for guidance on effective coat weights. Tanner provides an explicit example of a suitable coat weight for a similar biodegradable product. A POSITA would combine the teachings to use a proven coat weight from Tanner with Nakagawa’s cup design to ensure proper performance, especially since both references teach using extrusion coating.
  • Expectation of Success: Because Tanner demonstrates the successful use of a specific coat weight range for a biodegradable polymer on a paper-based product, a POSITA would have a reasonable expectation of success in applying Tanner’s disclosed coat weights to the similar system in Nakagawa.

4. Key Technical Contentions (Beyond Claim Construction)

• Petitioner argued that the Patent Owner misled the Examiner during prosecution regarding a prior art reference (Yamawaki). The Patent Owner allegedly mischaracterized Yamawaki's disclosed coat weight (5 to 30 g/m²) as not being "equivalent to or even comparable to" the claimed range (5 to 30 lbs/3000 ft²). Petitioner contended that a simple mathematical conversion shows Yamawaki’s range is 3.07 to 18.42 lbs/3000 ft², which substantially overlaps and falls within the claimed range, and that the allowance was therefore based on an error.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under §314(a) based on Fintiv, stating it has no knowledge of any parallel proceeding involving the ’126 patent.
• Petitioner also argued that denial under §325(d) is inappropriate because the primary references relied upon (Cleveland, Nakagawa, and Tanner) were never considered by the Examiner during prosecution. The petition is therefore not cumulative of arguments the Examiner previously evaluated.

6. Relief Requested

• Petitioner requests institution of IPR and cancellation of claims 1-3 and 11 of Patent 8,637,126 as unpatentable.