Controlled-Release Fertilizers Patents: Top Filers & Trends 2026
- Filing has cooled since its 2019 peak. 53 families that year against 34 in 2017 and only 24 at the 2022 midpoint — this is a maturing claim space, not a growing one.
- China now leads on filing volume. 222 records at the Chinese receiving office versus 107 in the United States, 63 at the EPO, 50 in Japan, and 49 each in Australia and Canada.
- The most-cited prior art is decades old. The five most-cited records date back to attrition-resistant coating patents from the 1970s-80s, meaning today's filers are still designing around foundational particle-coating claims.
What the controlled-release fertilizer patent record shows
Controlled-release and slow-release fertilizer patents cluster around one problem: how to coat a granule so nutrients release on a schedule that matches plant uptake rather than leaching or volatilising early. The dataset covers 709 patent families filed between 2015 and mid-2026 under IPC codes for fertiliser mixtures, nitrogen fertilisers and related coating chemistry. C05G, the core fertiliser-mixture subclass, appears in nearly every record, while polymer and coating-adjacent classes such as C08G and C09D show up in a much smaller minority — a sign that most invention still happens inside formulation rather than in new coating polymer chemistry itself.
Filing activity peaked in 2019 and has since declined toward the level seen at the start of the window, with the most recent year necessarily undercounted because publication lags filing by roughly 18 months. Reading the trend as flat-to-declining, rather than as a collapse, is the safer interpretation until another year or two of data clears the publication lag.
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Filing trend and technology composition
Two views of the same 709-family dataset: how filing volume has moved year over year, and which IPC subclasses carry the claims.
A 2019 peak followed by a decline
Families rose from 34 in 2017 to a peak of 53 in 2019, then eased back toward 24 at the 2022 midpoint and down to 7 in the most recent, still-incomplete year. Treat the last one to two years as undercounted rather than as evidence of a sudden drop-off.
Fertiliser mixtures dominate, coating chemistry is the minority
C05G (fertiliser mixtures) appears in 701 of 709 records, essentially the whole dataset, with C05C (nitrogen fertilisers) a distant second at 214. Coating-specific classes — C08G condensation polymers at 67 and C09D coatings/paints at 36 — are present but small, indicating most claims sit in nutrient formulation and release-profile design rather than in novel polymer coating science.
Shares are the percentage of the 709 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Controlled-Release Fertilizers with Eureka
This page is one run against one query. Ask Eureka your own question about controlled-release fertilizers and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art still shaping freedom to operate
Renewable material-based furandicarboxylic acid coating material of polyurethane controlled release fertilizer
A renewable material-based furandicarboxylic acid (Bio-FDCA) coating material for a polyurethane controlled-release fertilizer is prepared by cross-linking a Bio-FDCA-derived polyester polyol with an isocyanate. The coating material is sprayed onto granular fertilizer and cross-linked in situ to form a film layer, producing the controlled-release fertilizer. The filing introduces a furan ring structure into the coating chemistry, positioning it as a bio-based alternative to petroleum-derived polyurethane coatings.Filed 2024-09-26 by Qingyang Economic Development Zone.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5211985A | Multi-stage process for continuous coating of fertilizer particles | 175 |
| 2 | US4711659A | Attrition resistant controlled release fertilizers | 175 |
| 3 | US4019890A | Method for producing coated fertilizer | 155 |
| 4 | US4804403A | Attrition-resistant, controlled release fertilizers | 140 |
| 5 | US6231633B1 | Granular coated fertilizer and method for producing the same | 134 |
| 6 | US4042366A | Controlled release fertilizer | 125 |
| 7 | US5219465A | Sulfur coated fertilizers and process for the preparation thereof | 122 |
| 8 | US3264089A | Slow release fertilizer granule having a plurality of urethane resin coatings | 114 |
| 9 | US6358296B1 | Slow-release polyurethane encapsulated fertilizer using oleo polyols | 111 |
| 10 | CN101323545A | 可降解型聚合物包膜控释肥料及其制备方法与专用包膜材料 | 102 |
Citation counts favor older records simply because they have had more time to accumulate citations inside this corpus — read them as markers of foundational influence, not of current commercial relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for filing strategy
Three patterns in the data matter more than any single ranking: where claim density sits, where receiving offices concentrate, and what the oldest cited art still controls.
Growth has flattened, not accelerated
The 2019 peak of 53 families has not been matched since; the 2022 midpoint of 24 sits well below it, and the most recent year's count of 7 (still incomplete due to publication lag) continues that trajectory. A new entrant should not assume this is a growth market on filing volume alone.
China is the largest single filing destination
With 222 records at the Chinese receiving office against 107 in the US, 63 at the EPO and 50 in Japan, clearance searches that stop at USPTO and EPO databases will miss the largest single share of active filings.
Claims cluster in formulation, not coating polymer science
Almost every record touches C05G fertiliser mixtures, while coating-specific classes C08G and C09D appear in well under a tenth of records each. Novel polymer chemistry for the coating layer itself is a comparatively open, less-crowded angle inside this dataset.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to controlled-release fertilizers, with the prior art for and against each one.
Who is filing, and how they combine
Assignee activity in this dataset is led by a small group of chemicals and agri-nutrient companies, several of which co-file with named partners, alongside a long tail of single-filing entrants including universities.
Coating suppliers pair with agri-nutrient specialists
The strongest co-assignee link in the dataset pairs a specialty chemicals company with an agricultural technology firm at 16 shared families, with two further pairs at 12 and 10 — a sign that coating material IP and agronomic application IP are often held jointly rather than by one party alone.
Several established filers show no latest-year activity
A number of the historically active assignees, including a major university filer showing a -100% year-on-year change, register zero families in the latest year of the dataset. Given the ~18-month publication lag, this likely understates true recent activity rather than confirming an exit.
A broad base beneath a concentrated top
With 709 families spread across the full ranking and only a handful of co-assignee pairs, most entities in this space file independently, and the field beneath the most active names thins out quickly into single- or few-filing entrants.
| Assignee | Recent year | YoY |
|---|---|---|
| SABIC Global Technologies B.V. | 0 | — |
| OMS Investments, Inc. | 0 | — |
| Huntsman International LLC | 0 | — |
| Sulvaris Inc. | 0 | — |
| Purcell Agri-Tech, LLC | 0 | — |
| Shandong Agricultural University | 0 | -100% |
| Sumitomo Chemical Co., Ltd. | 0 | — |
| O M SCOTT & SONS CO | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is clearance, licensing, or R&D scoping.
Run a coating-chemistry-specific search
Because C08G and C09D classes are thin relative to C05G, a narrower search scoped to novel coating polymers rather than fertiliser mixtures broadly will surface less-crowded claim territory.
Explore coating chemistry in EurekaCheck China filings before finalizing FTO
With 222 of 709 records receiving at the Chinese office, any freedom-to-operate opinion that excludes Chinese filings is working from an incomplete picture of this field.
Search China filings in EurekaWatch for lagged recent activity
Assignees showing zero latest-year filings may simply be sitting inside the publication lag window; re-run momentum tracking in six to twelve months before concluding they have exited.
Track assignee momentum in EurekaCommon questions about controlled-release fertilizer patents
The core classification is C05G, fertiliser mixtures, which appears in 701 of the 709 families in this dataset. C05C (nitrogen fertilisers) is the next most common at 214 records, followed by smaller but relevant classes: B01J for chemical and physical processes, C08G for condensation polymers used in coatings, A01N for biocide/agrochemical combinations, and C09D for coatings and paints. A thorough prior-art search on a coated fertilizer invention should span at least these classes rather than relying on C05G alone.
Filing activity peaked in 2019 at 53 families and has trended down since, with the 2022 midpoint at 24 and the latest, still-incomplete year at 7. Because publication typically lags filing by around 18 months, the most recent one to two years understate true activity, so the honest read is flat-to-declining rather than a confirmed collapse. Anyone using this as a market-growth signal should wait for another filing cycle to clear the lag before drawing firm conclusions.
China leads with 222 records at its receiving office, well ahead of the United States at 107, the European Patent Office at 63, Japan at 50, and Australia and Canada at 49 and 45 respectively. This means a clearance search limited to US and European databases will miss the single largest bloc of filings in this field. Teams evaluating freedom to operate for products sold or manufactured in Asia should prioritise Chinese-language patent searches.
The most-cited records in this dataset are attrition-resistant and multi-stage coating patents dating to the 1970s and 1980s, including patents on continuous particle-coating processes and attrition-resistant controlled-release formulations. High citation counts here reflect decades of accumulated influence inside the corpus rather than current commercial dominance, since older patents simply have more time to be cited. Even so, foundational coating-process claims from this era often remain the baseline that later, more specific formulation patents are drafted around.
Relative to the dense C05G fertiliser-mixture claim space, coating-polymer-specific classes such as C08G and C09D are thinly represented, at 67 and 36 records respectively out of 709. Sub-areas like bio-based coating chemistries, non-polyurethane biopolymer coatings, and release-profile feedback mechanisms show comparatively low filing density. These branches are worth a dedicated novelty search before committing R&D budget, since they sit adjacent to heavily claimed formulation territory without being as crowded themselves.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.