Solenis Tech v. Buckman Laboratories

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Solenis Technologies, L.P. (Delaware), Solenis Switzerland GmbH (Switzerland), and Solenis LLC (Delaware)
  • Defendant: Buckman Laboratories, Inc. (Tennessee), Buckman Laboratories International, Inc. (Tennessee), and Bulab Holdings, Inc. (Tennessee)
  • Plaintiff’s Counsel: Adams and Reese LLP
• Case Identification: 2:23-cv-02413, W.D. Tenn., 07/07/2023
• Venue Allegations: Venue is alleged to be proper as the Defendant entities are incorporated in Tennessee, reside in the Western District of Tennessee, maintain a regular and established place of business in the district, and are believed to have committed acts of infringement within the district.
• Core Dispute: Plaintiff alleges that Defendant’s on-site generation of glyoxalated polyacrylamide (GPAM) chemical additives, and their subsequent use in papermaking, infringes patents related to methods of preparing such additives, the compositions themselves, and their use in strengthening paper products.
• Technical Context: The technology at issue involves thermosetting polymers used as strengthening agents in the paper and paperboard industry to improve the final product's wet and dry strength.
• Key Procedural History: The complaint details pre-suit correspondence beginning on May 13, 2022, in which Plaintiff notified Defendant of the Asserted Patents and its belief of infringement. The complaint characterizes Defendant's responses as non-substantive, which forms the basis for the allegations of willful infringement.

Case Timeline

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 8,703,847 - "Glyoxalation of Vinylamide Polymer" (Issued Apr. 22, 2014)

The Invention Explained

• Problem Addressed: The patent’s background describes prior art methods for creating glyoxalated polyvinylamide adducts (used as paper strengthening agents) as inefficient. Specifically, when the reaction was stopped to prevent gelling, a significant portion—approximately half—of the key glyoxal reactant remained unconsumed and thus did not contribute to the final product's function as a strength aid (’847 Patent, col. 2:40-49). These prior art adducts also suffered from poor storage stability and the risk of forming an unusable gel (’847 Patent, col. 2:25-32, 2:49-51).
• The Patented Solution: The invention discloses a method and composition that overcomes these problems by controlling the concentration of the vinylamide polymer during the reaction. By keeping the concentration "less than about 4 weight percent," the reaction can proceed more efficiently without the risk of gelling, leading to higher consumption of the glyoxal reactant and a more stable, effective final product (’847 Patent, Abstract; col. 3:20-28). The patent claims both the method of preparation under these low-concentration conditions and the resulting polymer composition defined by specific molecular weight and viscosity parameters (’847 Patent, col. 8:12-38).
• Technical Importance: This approach enabled the creation of more stable and efficient paper strengthening agents, which could be produced on-site at paper mills to improve paper quality while reducing chemical waste (Compl. ¶¶18, 21).

Key Claims at a Glance

• The complaint asserts independent claims 1 (a method of preparation) and 8 (a composition) (Compl. ¶36).
• Essential Elements of Independent Claim 1:
  • A method for preparing a cellulose reactive functionalized polyvinylamide adduct comprising reacting a substantially aqueous reaction mixture of a vinylamide polymer and a cellulose reactive agent.
  • The vinylamide polymer has an average molecular weight from 70,000 to 500,000 Daltons.
  • The concentration of the vinylamide polymer is less than about 4 weight percent of the reaction mixture "at any stage during the adduct reaction."
  • The resulting adduct has a viscosity of no more than 30 centipoise (measured under specific conditions).
• Essential Elements of Independent Claim 8:
  • A substantially aqueous glyoxalated-polyvinylamide thermosetting polymer composition comprising a reaction product of a vinylamide polymer and glyoxal, with substantially no organic liquid.
  • The vinylamide polymer has an average molecular weight from 70,000 to 500,000 Daltons and a concentration from about 0.1 to less than 4 wt. %.
  • The reaction product has a viscosity of no more than 30 centipoise (measured under specific conditions).

U.S. Patent No. 8,222,343 - "Glyoxalation of Vinylamide Polymer" (Issued Jul. 17, 2012)

The Invention Explained

• Problem Addressed: Like its family members, this patent addresses the gelling risk and inefficient reactant consumption in prior art methods for producing paper strengthening agents (’343 Patent, col. 2:25-49).
• The Patented Solution: The invention introduces the concept of a "Critical Concentration," which is defined as the specific vinylamide polymer concentration that marks an inflection point in the reaction mixture's viscosity behavior. By conducting the reaction at a concentration below or very close to this "Critical Concentration," the process avoids gelling, maximizes glyoxal consumption, and enhances shelf-life (’343 Patent, Abstract; col. 9:12-24). The patent claims the final paper or board product made using an adduct prepared by this specific process, as well as the method of using the adduct to strengthen paper (’343 Patent, col. 18:14-19:40).
• Technical Importance: The "Critical Concentration" provides a precise, scientifically defined parameter for process control, allowing for a more optimized and repeatable method for producing high-performance paper strengthening agents (Compl. ¶19).

Key Claims at a Glance

• The complaint asserts independent claims 1 (a product-by-process claim) and 12 (a method of use claim) (Compl. ¶¶59, 69).
• Essential Elements of Independent Claim 1:
  • A paper or board comprising a cellulose reactive functionalized polyvinylamide adduct.
  • The adduct is prepared by a process of reacting a vinylamide polymer and a cellulose reactive agent.
  • The concentration of the polymer is "below, equal to or no more than 1% above a Critical Concentration," where "Critical Concentration" is defined as the inflection point for viscosity behavior during the reaction.
  • The adduct has a viscosity of no more than 30 centipoise (measured under specific conditions).
  • The reaction is run in a continuous or batch mode.
• Essential Elements of Independent Claim 12:
  • A method for increasing paper strength comprising a) adding the adduct to a cellulosic fiber slurry or b) applying the adduct to a wet web, paper, or board.
  • The adduct is prepared by the same process recited in Claim 1, with the same limitations regarding "Critical Concentration," viscosity, and continuous/batch mode operation.

Multi-Patent Capsule: U.S. Patent No. 7,875,676

• Patent Identification: U.S. Patent No. 7,875,676, "Glyoxalation of Vinylamide Polymer", issued January 25, 2011 (Compl. ¶16).
• Technology Synopsis: As the parent of the other asserted patents, the ’676 Patent discloses a method for preparing cellulose-reactive polyvinylamide adducts used as paper strengthening agents. It addresses prior art problems of gelling and inefficient reactant use by teaching a method of conducting the reaction near a "Critical Concentration," which is a key inflection point for the mixture's viscosity. This approach is described as minimizing gelling risk and enhancing the shelf-life and performance of the resulting adduct (’676 Patent, Abstract; Compl. ¶20).
• Asserted Claims: The complaint asserts at least independent claim 1 (Compl. ¶97).
• Accused Features: The accused features are Defendant's activities of "providing, establishing, or operating equipment for the generation of GPAM at one or more third-party facilities" (Compl. ¶97).

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are Defendant Buckman’s glyoxalated polyacrylamide (GPAM) products and the services and equipment used for generating GPAM on-site at third-party paper-making facilities, marketed under the Bubond® brand (Compl. ¶¶22, 39).

Functionality and Market Context

• The complaint alleges that Buckman establishes and operates equipment at customer facilities (i.e., paper mills) for the on-site generation of GPAM (Compl. ¶23). This GPAM is a chemical agent that functions as a paper strengthener when added during the manufacturing process (Compl. ¶1). The complaint positions Buckman’s Bubond® products and on-site generation services as directly competitive with Plaintiff’s Hercobond® brand technology (Compl. ¶21). The core of the infringement allegation is that the process performed by this on-site equipment, and the resulting chemical product, falls within the scope of the asserted patents (Compl. ¶39).

No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint bases its infringement allegations on "information and belief," noting that discovery is required to confirm the details of the accused process (Compl. ¶¶32, 34).

’847 Patent Infringement Allegations

’343 Patent Infringement Allegations

• Identified Points of Contention:
  • Evidentiary Questions: The complaint explicitly states that Plaintiff lacks conclusive evidence of infringement and requires discovery (Compl. ¶¶32, 34). The central dispute will therefore involve factual questions: Does the accused process actually meet the specific numerical limitations for molecular weight, concentration, and viscosity recited in the claims?
  • Technical Scope Questions: The ’343 and ’676 patents hinge on the term "Critical Concentration." A key technical question for the court will be whether the accused process operates with respect to this specific, empirically defined parameter, or if it merely operates at a generally low concentration that does not align with the patented concept.
  • Legal Scope Questions: For the product-by-process claim in the ’343 Patent (Claim 1), infringement requires proof that the final paper product was made by the claimed process. This raises potential questions of proof and divided infringement, as Buckman allegedly provides the equipment and/or chemical while its third-party customers perform the final papermaking.

V. Key Claim Terms for Construction

• The Term: "Critical Concentration" (in claims of the ’343 and ’676 Patents)

  • Context and Importance: This term is the technological centerpiece of the ’343 and ’676 patents, distinguishing them from prior art that may have simply used low concentrations without a guiding principle. The entire infringement analysis for these patents will likely depend on how this term is construed and applied to the facts of the accused process.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claims themselves provide a functional definition: "the concentration of the vinylamide polymer above which the viscosity increases... and below which, the viscosity decreases" (’343 Patent, col. 18:26-32). A party could argue that any process operating in the regime where viscosity decreases upon reaction meets this functional definition, regardless of whether the specific point was empirically calculated beforehand.
    • Evidence for a Narrower Interpretation: The specification describes the determination of this value through "empirical studies involving glyoxalation of the vinylamide polymer" in "a number of independent reaction solutions" (’343 Patent, col. 9:31-38). This language, along with a detailed example and data table (Table 2), may support an argument that the term requires a deliberate, pre-determined identification of this specific inflection point for a given polymer, not just incidental operation at a low concentration.

• The Term: "at any stage during the adduct reaction" (in Claim 1 of the ’847 Patent)

  • Context and Importance: This phrase defines the temporal scope of the requirement that the polymer concentration remain "less than about 4 weight percent." Its construction will determine whether a momentary or initial excursion above this limit avoids infringement.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification includes an example where a polymer "may be approximately 10 wt. % at onset, then diluted to less than 4 wt. % at 10% completion of the glyoxalation reaction" (’847 Patent, col. 3:23-25). This could support an argument that the concentration need not be below 4% at the absolute beginning of the reaction, allowing for initial mixing at higher concentrations before dilution.
    • Evidence for a Narrower Interpretation: The plain meaning of "at any stage" suggests an absolute requirement that the concentration never exceed the claimed limit once the reaction begins. This is reinforced by a preferred embodiment stating "the concentration be less than about 4 wt. % at the onset of functionalization" (’847 Patent, col. 3:26-28), which suggests the patentee contemplated the importance of maintaining low concentration from the very start of the reaction.

VI. Other Allegations

• Indirect Infringement: The complaint alleges both induced and contributory infringement.
  • Inducement: It is alleged that Buckman encourages its third-party customers to use the on-site GPAM generation equipment to perform the patented methods and to use the resulting GPAM in a way that infringes, and that Buckman does so knowing of the patents and that the encouraged acts constitute infringement (Compl. ¶¶47, 84, 107). Specific allegations include Buckman instructing third parties on how to use the GPAM in papermaking (Compl. ¶76).
  • Contributory Infringement: For the ’343 Patent, the complaint alleges Buckman contributes to infringement by supplying the on-site equipment and the GPAM it produces, asserting that the GPAM is a "material part of the invention" and a "non-staple article" that is "especially made or especially adapted for use in an infringement" (Compl. ¶¶69, 72, 75-76).
• Willful Infringement: The willfulness claims are based on alleged pre-suit knowledge. The complaint asserts that Solenis provided Buckman with "actual notice" of the Asserted Patents via a letter dated May 13, 2022, and that Buckman continued its allegedly infringing activities thereafter (Compl. ¶¶40, 62, 100).

VII. Analyst’s Conclusion: Key Questions for the Case

• A threshold issue for the court will be one of factual proof: given the complaint’s explicit reliance on "information and belief," will discovery produce evidence demonstrating that the accused on-site process actually operates within the specific numerical limitations (e.g., polymer concentration, molecular weight, viscosity) recited in the claims of the ’847 Patent?
• The case will likely turn on a central question of technical scope: does the accused process operate with reference to the specific, empirically-defined "Critical Concentration" as taught in the ’343 and ’676 Patents, or does it merely operate at a generally low concentration, raising the question of whether there is a fundamental mismatch between the accused process and the patents' core inventive concept?
• A key legal question will be one of liability for third-party acts: for claims directed to the final paper product and its method of use, can the plaintiff prove that the defendant, who allegedly supplies the on-site equipment and chemical precursor, is responsible for the infringing acts ultimately completed by its customers under the doctrines of indirect or divided infringement?