2:22-cv-12798
Sul4r Plus LLC v. Prolime Agriculture LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Sul4r-Plus, LLC (Delaware)
- Defendant: ProLime Agriculture LLC (Michigan)
- Plaintiff’s Counsel: Kerr, Russell and Weber, PLC; Moore & Van Allen PLLC
- Case Identification: 4:22-cv-12798, E.D. Mich., 11/17/2022
- Venue Allegations: Venue is alleged to be proper in the Eastern District of Michigan because the defendant is a Michigan company with a regular and established place of business in the district.
- Core Dispute: Plaintiff alleges that Defendant’s synthetic gypsum fertilizer products, and the method of making them, infringe a patent related to pelletizing fine synthetic gypsum for agricultural use.
- Technical Context: The technology addresses the challenge of making synthetic gypsum, an industrial byproduct with a very fine particle size, suitable for spreading with conventional agricultural equipment by forming it into durable pellets.
- Key Procedural History: The complaint alleges that Plaintiff provided Defendant with actual notice of the asserted patent and the alleged infringement via a letter dated September 8, 2022, approximately two months before filing suit.
Case Timeline
| Date | Event |
|---|---|
| 2012-08-08 | U.S. Patent No. 9,873,638 Priority Date |
| 2018-01-23 | U.S. Patent No. 9,873,638 Issue Date |
| 2022-09-08 | Plaintiff sends notice letter to Defendant |
| 2022-11-17 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,873,638 - “SYNTHETIC GYPSUM FERTILIZER PRODUCT AND METHOD OF MAKING”
- Issued: January 23, 2018.
The Invention Explained
- Problem Addressed: The patent identifies a problem with synthetic gypsum, an industrial byproduct. While a useful source of calcium and sulfur, its very fine particle size makes it difficult to handle and spread with standard agricultural equipment, as the moist, fine particles tend to stick to machinery ( ’638 Patent, col. 1:50-59).
- The Patented Solution: The invention provides a method for processing this fine synthetic gypsum by combining it with a binder composition (specifically including lignosulfonate) and forming it into pellets of a specified size and crush strength ( ’638 Patent, Abstract; col. 2:10-24). This process transforms the difficult-to-handle fine powder into a granular product suitable for conventional fertilizer spreaders.
- Technical Importance: This approach makes a large-volume industrial byproduct, which was previously difficult to use in agriculture, beneficially recyclable as a fertilizer ( ’638 Patent, col. 1:60-64; col. 2:1-4).
Key Claims at a Glance
- The complaint asserts independent claims 1 (a method claim) and 11 (a product claim) (Compl. ¶16).
- Independent Claim 1 (Method):
- feeding synthetic gypsum to a forming device;
- feeding a binder composition comprising lignosulfonate having 18% to 40% solids to the forming device; and
- forming the material to a mean pellet size guide number (SGN) from approximately 100 to 500,
- wherein the resulting pelletized synthetic gypsum has a crush strength from approximately 2 lbf to approximately 12 lbf.
- Independent Claim 11 (Product):
- A fertilizer comprising: pellets, the pellets comprising synthetic gypsum and a binder composition comprising lignosulfonate,
- wherein the binder composition initially has 18% to 40% solids at the time of contact with the synthetic gypsum,
- the pellets further comprising mean pellet SGN from approximately 100 to approximately 500,
- wherein the pellets have a crush strength from approximately 2 to approximately 12 lbf.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
The accused products are “G2016 Pro Gypsum Ag Grade” and “TG2016 Pro Gypsum Mini SGN 150” (collectively, the "Accused Products") (Compl. ¶3, ¶13).
Functionality and Market Context
The complaint alleges the Accused Products are synthetic gypsum fertilizers manufactured and sold by Defendant (Compl. ¶13, ¶17). Based on Defendant's promotional materials cited in the complaint, the products are described as "Premium, high-calcium, high-sulfur, pelletized gypsum product[s]" that deliver calcium and sulfate sulfur to soil (Compl. ¶14-15). The complaint positions the Accused Products as direct competitors to Plaintiff's own SUL4R-PLUS® fertilizer (Compl. ¶12). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
’638 Patent Infringement Allegations (Claim 1 - Method)
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| feeding synthetic gypsum to a forming device; | Defendant produces the Accused Products by feeding synthetic gypsum to a forming device. | ¶22 | col. 15:50-51 |
| feeding a binder composition comprising lignosulfonate having 18% to 40% solids to the forming device; | Defendant feeds a binder composition comprising lignosulfonate to its forming device. The complaint avers, pursuant to Rule 11(b)(3), that this binder has 18% to 40% solids, a fact likely to have evidentiary support after discovery. | ¶23-25 | col. 15:52-54 |
| and forming the material fed to the forming device to a mean pellet size guide number (SGN) from approximately 100 to approximately 500, | Defendant forms the material into pellets with a mean SGN between approximately 100 and 500. | ¶27 | col. 15:54-57 |
| wherein the resulting pelletized synthetic gypsum has a crush strength from approximately 2 lbf to approximately 12 lbf. | The resulting pellets have a crush strength between approximately 2 lbf and 12 lbf. | ¶29 | col. 15:57-59 |
’638 Patent Infringement Allegations (Claim 11 - Product)
| Claim Element (from Independent Claim 11) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| pellets, the pellets comprising synthetic gypsum and a binder composition comprising lignosulfonate, | The Accused Products are pellets made of synthetic gypsum and a binder containing lignosulfonate. | ¶31-35 | col. 16:11-14 |
| wherein the binder composition initially has 18% to 40% solids at the time of contact with the synthetic gypsum, | The complaint avers, pursuant to Rule 11(b)(3), that the binder composition used to make the Accused Products initially has 18% to 40% solids when it contacts the gypsum. | ¶37 | col. 16:14-16 |
| the pellets further comprising mean pellet SGN from approximately 100 to approximately 500, | The Accused Products comprise pellets with a mean SGN between approximately 100 and 500. | ¶38 | col. 16:16-18 |
| wherein the pellets have a crush strength from approximately 2 to approximately 12 lbf. | The Accused Products comprise pellets with a crush strength between approximately 2 and 12 lbf. | ¶39 | col. 16:18-20 |
Identified Points of Contention
- Evidentiary Question: A central issue will be whether Plaintiff can prove, through discovery, that Defendant’s binder composition meets the "18% to 40% solids" limitation. Plaintiff’s explicit reliance on Federal Rule of Civil Procedure 11(b)(3) for this allegation indicates it currently lacks direct evidence and that this is a known factual gap to be explored in litigation (Compl. ¶25, ¶37).
- Technical Questions: The analysis will require testing and evidence to determine if the Accused Products' physical properties (mean SGN and crush strength) fall within the specific numerical ranges recited in the claims.
V. Key Claim Terms for Construction
The Term
"binder composition comprising lignosulfonate having 18% to 40% solids" (Claim 1) / "binder composition initially has 18% to 40% solids at the time of contact" (Claim 11).
Context and Importance
This term is critical because it defines a key ingredient and its specific concentration, which appears to be a primary point of novelty. Practitioners may focus on this term because Plaintiff has already signaled its importance and potential for dispute by pleading the allegation under Rule 11(b)(3), suggesting a lack of pre-suit evidence on this specific technical parameter. The temporal qualifier "initially... at the time of contact" in claim 11 will also be important, as it focuses on the state of the binder during the manufacturing process, not its final state in the product.
Intrinsic Evidence for Interpretation
- Evidence for a Broader Interpretation: The specification lists lignosulfonate as one of many possible "water soluble binder" options, which could suggest a broader context for the invention ( ’638 Patent, col. 6:20-28). However, the claims themselves are more specific.
- Evidence for a Narrower Interpretation: The specification provides a specific working example of "A binder of lignosulfonate having 18% to 48% solids" ( ’638 Patent, col. 6:56-58). A party could argue that the claimed range of 18% to 40% is a precise and intentional selection, distinct from the broader example range, thereby supporting a strict interpretation of the claimed numerical bounds.
VI. Other Allegations
Indirect Infringement
The complaint includes a conclusory allegation that Defendant is "indirectly responsible for contributing to and/or inducing the infringement... by others" (Compl. ¶55). However, it does not plead any specific facts to support this claim, such as allegations that Defendant provides instructions or user manuals that encourage an infringing use by customers.
Willful Infringement
The willfulness claim is based on alleged pre-suit knowledge of the ’638 Patent. The complaint alleges that Plaintiff sent a letter on September 8, 2022, that provided notice of the patent and the alleged infringement, and that Defendant continued its accused activities after receiving this notice (Compl. ¶43-48, ¶58).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of evidentiary proof: can the Plaintiff, through discovery, produce evidence that Defendant’s manufacturing process uses a lignosulfonate binder with a solids concentration that falls within the specifically claimed "18% to 40%" range? The complaint’s reliance on Rule 11(b)(3) for this element frames this as the central factual dispute.
- The case will also turn on a question of technical convergence: does the physical composition of the Accused Products—specifically their mean pellet SGN and crush strength—factually align with the numerical ranges required by the asserted claims? This will likely be a battle of competing expert analyses and product testing.