PTAB

IPR2020-01121

Stahls' Inc v. Schwendimann Jodi

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Transfer on a Colored Base
  • Brief Description: The ’554 patent discloses a multi-layer image transfer sheet, commonly known as an "iron-on," and a method for its use. The technology aims to solve the problem of transferring images onto colored or dark fabrics by integrating a white, opaque background layer into the transfer sheet itself, thereby enabling a single-step application process.

3. Grounds for Unpatentability

Ground 1: Obviousness over Akada, Kronzer, and Oez - Claims 1-4 are obvious over Akada in view of Kronzer and Oez.

  • Prior Art Relied Upon: Akada (Patent 5,248,543), Kronzer (Patent 5,242,739), and Oez (Patent 5,665,476).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Akada taught a multi-layer image transfer sheet with nearly all the claimed structural elements, including an ink-receptive portion, a base portion, a silicone release coating, and the inclusion of white pigment to improve whiteness. However, Akada disclosed a generic acrylic adhesive, not the specifically claimed ethylene acrylic acid (EAA) resin. Kronzer was argued to cure this deficiency by teaching that EAA copolymers are "especially effective film-forming binders" for use in multi-layer heat transfer paper products. Petitioner asserted that Oez supplied the final missing element: the method step of using a protective cover paper during ironing to protect the film.
    • Motivation to Combine: A POSITA would combine Akada with Kronzer to use a known, particularly effective acrylic resin (EAA) for the disclosed purpose of binding layers in a heat transfer sheet. A POSITA would further incorporate the teaching from Oez to use a protective sheet, a well-known technique to protect the heat-receiving surface during ironing in a similar transfer process.
    • Expectation of Success: Because Kronzer and Oez addressed known materials and process steps within the same field of heat transfers for fabrics, a POSITA would have had a high expectation of success in implementing these modifications to the Akada system.

Ground 2: Obviousness over Asajima, Kronzer, and Oez - Claims 1-5 are obvious over Asajima in view of Kronzer and Oez.

  • Prior Art Relied Upon: Asajima (Patent 5,418,207), Kronzer (Patent 5,242,739), and Oez (Patent 5,665,476).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted this combination rendered claims 1-5 obvious. Asajima was presented as disclosing a thermal transfer sheet with a dye-receiving layer, an intermediate layer, an adhesive layer, and a releasable sheet. Asajima also taught incorporating white pigment into any of these layers to provide whiteness independent of the substrate color. Like Akada, Asajima taught a generic acrylic resin but not specifically EAA; Kronzer was again relied upon to supply the teaching of using EAA as a particularly effective binder. Petitioner argued that while Asajima described transferring the layers via heat, Oez provided the explicit teaching of a "positive print" method: first peeling the substrate and then applying the remaining film to the fabric, as recited in the claims. Oez also supplied the use of a protective cover paper.
    • Motivation to Combine: A POSITA would modify Asajima's system with Kronzer's teaching to use a superior EAA binder. A POSITA would have also been motivated to adopt the advantageous positive print application method taught by Oez, which simplifies cutting and aligning the image on dark textiles.
    • Expectation of Success: The combination involved applying known, effective materials (EAA from Kronzer) and advantageous process steps (positive printing from Oez) to the known transfer sheet structure of Asajima, leading to a reasonable expectation of success.

Ground 3: Anticipation by Asajima - Claims 6-7 are anticipated by Asajima.

  • Prior Art Relied Upon: Asajima (Patent 5,418,207).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Asajima, by itself, disclosed every element of apparatus claims 6 and 7. Asajima's thermal transfer image-receiving sheet was argued to be the claimed "image transfer sheet." Its dye-receiving layer was the "ink receptive portion," its releasable polyester film was the "base paper portion," and its optional peeling layer with silicone resin was the "silicone release portion." Petitioner contended that Asajima taught using polymers like polyamide in its layers that have melting points within the claimed range (20°C to 300°C) and that contact the ink receptive portion. The teaching to include white pigment was argued to satisfy the limitation of providing an opaque background. For claim 7, Petitioner argued a POSITA would have understood that the combined weight of Asajima's silicone-coated substrate falls within the claimed weight range.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including claims 1-4 over Akada, Kronzer, and Hare (using Hare as an alternative to Oez for teaching a protective sheet); claim 5 over combinations including Takao (for teaching a distinct white layer); claims 6-7 over Asajima as modified by Kronzer; and claim 8 over Asajima as modified by Terufumi (for teaching a specific release force value).

4. Key Claim Construction Positions

  • "White Layer": Petitioner argued that based on clear disavowals made by the Patent Owner during a prior interference proceeding, all challenged claims must be construed to require a "white layer" that not only contains pigment but also comprises a polymer that "must melt and must mix" with another layer during application. This construction was argued to be critical, as it requires the prior art to teach not just layers with pigment, but adjacent, melt-compatible polymers that would mix upon heating, a feature Petitioner contended was met by the proposed combinations.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-8 of the ’554 patent as unpatentable.