Sul4r-Plus v. Prolime Agriculture: Gypsum Fertilizer Patent Dismissed With Prejudice
Sul4r-Plus, LLC brought a patent infringement action against Prolime Agriculture, LLC in the Eastern District of Michigan over US9873638B2, a patent covering synthetic gypsum fertilizer products and their manufacture. The parties reached a stipulated resolution after 572 days, resulting in a dismissal with prejudice and no costs awarded to either side.
Stipulated end to a synthetic gypsum fertilizer patent dispute
Sul4r-Plus, LLC filed suit against Prolime Agriculture, LLC on 17 November 2022 in the Eastern District of Michigan, asserting infringement of US9873638B2, which protects a synthetic gypsum fertilizer product and the method of making it. The case centred on Prolime’s agricultural lime and gypsum products, which Sul4r-Plus alleged fell within the scope of the asserted patent claims.
The case closed on 11 June 2024 through a court-approved stipulation of the parties (ECF No. 32), resulting in dismissal with prejudice and no costs or fees awarded to either party. Dismissal with prejudice is a final adjudication on the merits — Sul4r-Plus is permanently barred from reasserting the same patent claims against Prolime arising from the same conduct. The mutual no-costs arrangement suggests the parties negotiated symmetrical exit terms.
The 572-day duration before stipulated dismissal is consistent with cases that resolve after substantive pre-trial activity, such as claim construction exchanges or licensing negotiations, though the public record does not disclose the specific trigger. The absence of any fee award to either side is notable — it is consistent with a negotiated settlement rather than a litigation victory. The underlying commercial terms, if any, remain confidential.
Filing to Dismissed with Prejudice in 572 days
572 days — above the median duration for stipulated dismissals in E.D. Mich. patent cases
Dismissed with prejudice: what the stipulated order means for both parties
Stipulated dismissal with prejudice forecloses re-filing
A dismissal with prejudice entered on stipulation of the parties operates as a final judgment on the merits. Under Federal Rule of Civil Procedure 41(a)(1)(A)(ii), both parties signed off on the dismissal, and the court so ordered it. Sul4r-Plus cannot bring the same patent claims against Prolime based on the same accused conduct in any federal court going forward.
Rule 41 — final on the meritsSul4r-Plus surrenders the right to re-litigate these claims
By agreeing to dismissal with prejudice, Sul4r-Plus permanently relinquishes its ability to assert US9873638B2 against Prolime for the conduct at issue. However, the patent itself remains valid and enforceable against third parties. The no-costs clause means Sul4r-Plus recovered no damages or fees — any commercial resolution reached between the parties is not disclosed in the public record.
Patent survives — enforcement against others intactProlime Agriculture achieves finality without an invalidity ruling
Prolime secures a permanent end to this specific litigation without the patent being invalidated. No costs were awarded, suggesting Prolime did not obtain an ‘exceptional case’ fee award under 35 U.S.C. § 285. Crucially, the patent remains on the register and could theoretically be asserted against Prolime’s competitors or, under different circumstances, Prolime itself in future product lines not covered by this stipulation.
Case closed — no invalidity findingSynthetic gypsum fertilizer IP landscape remains legally unsettled
Because the dismissal was with prejudice by stipulation rather than on invalidity grounds, US9873638B2 retains full presumptive validity. Competing manufacturers of synthetic gypsum fertilizer products face continued exposure to this patent. The resolution is consistent with a licensing agreement or commercial settlement between these specific parties, but the patent’s enforceability against the broader market is unchanged.
Patent enforceable against third partiesFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Sul4r-Plus, LLC | Company | Agricultural input IP company — holder of US9873638B2 for synthetic gypsum fertilizerSearch in Eureka ↗ |
| Defendant | Prolime Agriculture, LLC | Company | Agricultural lime and gypsum products company operating in the Midwest marketSearch in Eureka ↗ |
| Plaintiff counsel | Fred K. Herrmann | Attorney | Counsel for Sul4r-Plus, LLCSearch in Eureka ↗ |
| Plaintiff counsel | J. Mark Wilson | Attorney | Counsel for Sul4r-Plus, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Jeffrey D. Dyess , I | Attorney | Counsel for Sul4r-Plus, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Jessica Lynn Zurlo | Attorney | Counsel for Sul4r-Plus, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Stephanie Scruggs | Attorney | Counsel for Sul4r-Plus, LLCSearch in Eureka ↗ |
| Plaintiff law firm | Bradley Arant Boult Cummings LLP | Law Firm | Representing Sul4r-Plus, LLCSearch in Eureka ↗ |
| Plaintiff law firm | Kerr Russell | Law Firm | Representing Sul4r-Plus, LLCSearch in Eureka ↗ |
| Plaintiff law firm | Moore & Van Allen PLLC | Law Firm | Representing Sul4r-Plus, LLCSearch in Eureka ↗ |
| Defendant counsel | Jessica E. Fleetham | Attorney | Counsel for Prolime Agriculture, LLCSearch in Eureka ↗ |
| Defendant counsel | Steven C. Susser | Attorney | Counsel for Prolime Agriculture, LLCSearch in Eureka ↗ |
| Defendant law firm | Evia Law PLC | Law Firm | Representing Prolime Agriculture, LLCSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Michigan Eastern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The court’s order adopts the parties’ stipulation verbatim, confirming dismissal with prejudice and a mutual no-costs arrangement. The ‘with prejudice’ designation is legally significant: it bars Sul4r-Plus from re-filing the same infringement claims against Prolime arising from the same accused conduct. The explicit waiver of costs by both sides is consistent with a negotiated resolution rather than a litigation win, though no commercial terms are disclosed in the public record.
US9873638B2 — Synthetic gypsum fertilizer product and method of making
US9873638B2 (application number US13/962903) protects a synthetic gypsum fertilizer product and the process by which it is manufactured. Synthetic gypsum — typically a byproduct of flue-gas desulfurisation in coal-fired power plants — has growing agricultural application as a soil amendment delivering calcium and sulfur. Patents in this space cover specific formulations, processing steps, and product characteristics that distinguish commercially viable fertilizer-grade gypsum from raw industrial byproduct.
For the agricultural inputs sector, US9873638B2 represents an attempt to establish proprietary IP around a product category that is growing in demand as precision agriculture increases focus on soil chemistry. Sul4r-Plus’s decision to enforce this patent against Prolime Agriculture — a direct market competitor — signals that the patent holder views its claims as commercially meaningful. Competitors in the synthetic gypsum fertilizer space, including producers, distributors and formulators, should regard this patent as an active strategic asset in Sul4r-Plus’s portfolio.
Should you run an FTO against US9873638B2?
Any company manufacturing, distributing, or formulating synthetic gypsum-based fertilizer products should assess freedom to operate against US9873638B2. The patent covers both the product and the method of making it — meaning exposure is not limited to finished fertilizer sellers. Upstream processors of industrial gypsum byproducts, toll manufacturers, and private-label formulators may all fall within the patent’s reach depending on claim scope and their specific processes.
PatSnap Eureka’s FTO Search Agent can map the claims of US9873638B2 against your product specifications and manufacturing process, identify relevant prior art that may support invalidity arguments, and surface any continuation or related applications in the Sul4r-Plus portfolio. Running a structured FTO before entering or expanding in the synthetic gypsum fertilizer market is a prudent step given this patent’s demonstrated enforcement history.
Run a freedom-to-operate analysis on US9873638B2 to assess your product’s exposure
Run FTO in Eureka →Similar patent cases in agricultural inputs and fertilizer technology
Related infringement actions involving agricultural gypsum, soil amendment, and fertilizer process patents in U.S. district courts, including E.D. Michigan.
What this case signals for the agricultural fertilizer IP landscape
A stipulated dismissal with prejudice after 572 days typically signals resolved commercial interests — but the underlying patent remains a live enforcement tool.
US9873638B2 is still enforceable — competing gypsum fertilizer makers are exposed
The dismissal with prejudice applies only as between Sul4r-Plus and Prolime Agriculture. The patent was not invalidated, not held unenforceable, and not disclaimed. Any manufacturer operating in the synthetic gypsum fertilizer space should treat this patent as an active enforcement risk and consider whether their products and methods fall within its claims.
No costs order is a structural signal worth reading carefully
When both parties agree to bear their own costs in a dismissal with prejudice, it typically signals a negotiated exit — potentially including a licence, supply arrangement, or market division. Patent professionals monitoring Sul4r-Plus’s enforcement strategy should note that this outcome does not indicate weakness in the patent; it may reflect commercial pragmatism on both sides.
Sul4r-Plus v Prolime — key questions answered
Dismissal with prejudice in Case No. 2:22-cv-12798 means the court entered a final judgment that permanently bars Sul4r-Plus from re-filing the same patent infringement claims against Prolime Agriculture based on the same accused conduct. The dismissal was entered by stipulation of both parties under Federal Rule of Civil Procedure 41(a)(1)(A)(ii), making it a consensual but legally final resolution.
Yes. The dismissal with prejudice in this case applies only to the claims between Sul4r-Plus and Prolime Agriculture. The court made no ruling on the validity or enforceability of US9873638B2. The patent retains its full presumptive validity under 35 U.S.C. § 282 and remains enforceable against third parties who manufacture or sell synthetic gypsum fertilizer products covered by its claims.
The court’s order expressly provides that the dismissal is ‘without costs or fees to either party.’ This mutual no-costs arrangement was part of the parties’ stipulation. It suggests neither party sought or obtained an ‘exceptional case’ fee award under 35 U.S.C. § 285, which is consistent with a negotiated commercial resolution rather than a clear litigation victory for either side.
US9873638B2 covers a synthetic gypsum fertilizer product and the method of making it. Synthetic gypsum, often derived from flue-gas desulfurisation processes, is used as a soil amendment in agriculture to deliver calcium and sulfur. The patent (application number US13/962903) protects specific product formulations and manufacturing processes that distinguish fertilizer-grade synthetic gypsum from raw industrial byproduct.
The case ran for 572 days, from filing on 17 November 2022 to closure on 11 June 2024. This duration is above what might be expected for a straightforward stipulated dismissal and suggests the parties engaged in meaningful pre-trial activity — potentially including claim construction, discovery, or licensing discussions — before agreeing to the stipulated dismissal with prejudice that ended the case.
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