3M Co v. Bay Materials LLC

1. Case Identification

• Case #: IPR2022-01214
• Patent #: 10,946,630
• Filed: July 11, 2022
• Petitioner(s): 3M Company
• Patent Owner(s): Bay Materials, LLC
• Challenged Claims: 1-4, 7-11, and 13

2. Patent Overview

• Title: Dual Shell Dental Appliance and Material Constructions
• Brief Description: The ’630 patent discloses polymeric sheet compositions for making dental appliances, featuring a hard-soft-hard multilayer structure. The composition has hard outer layers with a flexural modulus of 1,000-2,500 MPa and a soft elastomeric inner core with a modulus of 50-500 MPa.

3. Grounds for Unpatentability

Ground 1: Claims 1-4, 7-11, and 13 are obvious over Hinz in view of the Durasoft (TPU/PC) Data Sheet.

• Prior Art Relied Upon: Hinz (WO 2010/043419) and the Durasoft (TPU/PC) Data Sheet.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Hinz disclosed the core inventive concept: a three-layer dental splint with two hard outer layers and a soft inner layer. Hinz specifically identified polycarbonate (PC) as a preferred hard material and thermoplastic polyurethane (TPU) as a preferred soft material. The Durasoft (TPU/PC) Data Sheet provided specific properties for a commercially available PC/TPU composite film intended for dental splints. The PC layer’s elastic modulus (2,400 MPa) and the TPU layer’s elastic modulus (172 MPa) and hardness values fell squarely within the ranges claimed in the ’630 patent. Petitioner further asserted that by applying elastic beam theory to a three-layer structure with specific thicknesses disclosed by Hinz and material properties from Durasoft, the resulting overall flexural modulus (1,560 MPa) satisfied the limitation of independent claim 1 (750-2,000 MPa).
  • Motivation to Combine: A POSITA would combine these references because Hinz expressly disclosed using the trade name material "DURASOFT®" from Scheu-Dental to create its multilayer splints. The Durasoft (TPU/PC) Data Sheet provided the specific properties of the exact materials (PC and TPU) for the exact application (dental splints) that Hinz taught. The motivation was therefore explicit and compelling.
  • Expectation of Success: A POSITA would have had a high expectation of success, as the combination involved using materials (PC and TPU) according to their intended and disclosed purpose in a structure explicitly taught by Hinz. The manufacturing methods, such as thermoforming, were conventional and well-understood in the art.

Ground 2: Claims 1-4, 7-11, and 13 are obvious over Hinz, the Durasoft (TPU/PC) Data Sheet, and the Durasoft (TPU/PETG) Data Sheet.

• Prior Art Relied Upon: Hinz (WO 2010/043419), Durasoft (TPU/PC) Data Sheet, and Durasoft (TPU/PETG) Data Sheet.
• Core Argument for this Ground:
  • Prior Art Mapping: This ground presented an alternative to Ground 1, substituting a different known hard material. Petitioner argued that Hinz taught that the hard outer layer could be made of PC or polyethylene terephthalate (PET). The Durasoft (TPU/PETG) Data Sheet disclosed a version of the Durasoft product where the hard layer was PETG, a common copolyester of PET. The PETG layer’s elastic modulus (2,200 MPa) fell within the claimed hard material range. Petitioner contended the TPU layer in both Durasoft products was essentially identical. The calculated overall flexural modulus for a PETG-TPU-PETG structure (1,439 MPa) also fell within the claimed range.
  • Motivation to Combine: A POSITA would be motivated to substitute PETG for PC because Hinz explicitly suggested PET as an alternative hard material. Furthermore, a POSITA would have known that Scheu Dental offered a PETG version of its Durasoft product. This made substituting PETG for PC a simple and obvious design choice among a small number of known options for the same purpose.
  • Expectation of Success: The substitution of one well-known thermoplastic (PETG) for another (PC) in a dental appliance application was a predictable and routine modification for a POSITA, carrying a high expectation of success.

Ground 3: Claims 1-4, 7-11, and 13 are obvious over the combination of Ground 1 or Ground 2, further in view of Sun.

• Prior Art Relied Upon: The combination from Ground 1 or Ground 2, further in view of Sun (Application # 2004/0224283).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground was asserted to the extent the Patent Owner contested that the specific flexural modulus range of claim 1 was not obvious from Grounds 1 or 2. Sun taught making flexible dental splints and disclosed preferred flexural modulus values (e.g., less than 1,723 MPa) to ensure the appliance was easily removable without discomfort.
  • Motivation to Combine: A POSITA, seeking to optimize the flexibility and "better insertion and removal behavior" touted by Hinz, would have been motivated to look to Sun’s teachings. Sun provided explicit target values for flexural modulus to achieve that very goal. A POSITA would therefore be motivated to adjust the layer thicknesses taught by Hinz, using the Durasoft materials, to achieve the specific, beneficial flexural modulus values taught by Sun.
  • Expectation of Success: As Hinz already disclosed ranges for layer thicknesses and suitable materials, a POSITA would find it a matter of routine optimization to select parameters to meet the target flexural modulus from Sun with a high likelihood of success.

4. Key Technical Contentions (Beyond Claim Construction)

• Petitioner argued that while the term "flexural modulus" could be considered indefinite in co-pending litigation due to the existence of different measurement standards, this did not preclude an obviousness finding in the IPR. Petitioner contended that under any accepted standard, the flexural modulus values calculated from the prior art combinations fell well within the claimed ranges, making the claims obvious regardless of the specific test method used.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under Fintiv would be inappropriate because the co-pending district court trial was scheduled for May 2024, well after the statutory deadline for a Final Written Decision, and the presiding judge routinely grants stays pending IPR. The petition was filed promptly after the patent owner identified the asserted claims, and Petitioner offered to stipulate it would not pursue the same grounds in district court.
• Petitioner also argued against denial under §325(d), asserting that although the primary reference, Hinz, was cited during prosecution, it was a German-language document for which no English translation was provided to the Examiner. Therefore, the Examiner never substantively considered the key teachings relied upon in the petition.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-4, 7-11, and 13 of the ’630 patent as unpatentable.