Water-Soluble Polymers & Flocculant Patents: Who Leads Now 2026
- Filing has cooled since 2018. the peak year (44 families) sits early in the window and the count has fallen every year since, down to single digits by the most recent filed year.
- Wastewater treatment dominates the claim map. C02F accounts for 564 of 812 records, nearly seven in ten filings, well ahead of separation processes and addition-polymer chemistry.
- The largest assignees have gone quiet. every one of the top-named assignees shows zero filings in the latest year, a sign the incumbents are defending existing grants rather than expanding claim scope.
Filing growth compares 2021 (5 records) with 2024 (6) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 812 records in scope (CR5), not by the ranked leaders only.
A mature filing field with a shrinking annual intake
Water-soluble polymers and flocculants sit at the intersection of wastewater treatment, separation engineering and vinyl-polymer chemistry. The 812 patent families in this dataset span filings from 2017 through the current partial year, concentrated overwhelmingly in C02F water and wastewater treatment and B01D separation processes, with a smaller but persistent thread of pure polymer chemistry under C08F. Filing activity peaked in 2018 at 44 families and has declined through the midpoint year and beyond, a pattern more consistent with a field settling into incremental defence than one still expanding its claim frontier.
Because publication typically lags filing by around eighteen months, the last one or two years in any trend chart will understate real activity. Even allowing for that lag, the multi-year decline from the 2018 peak points to a field where core flocculant and dewatering chemistry claims are largely staked out, and new filings are increasingly narrow formulation or process variants rather than foundational compositions.
Filing trend and technology composition
Two views of the same 812-family dataset: how filing volume has moved year over year, and how those filings split across the IPC subclasses that define the technology.
Filings declined from a 2018 peak
From 37 families in 2017 to a peak of 44 in 2018, the trend falls to 12 at the 2022 midpoint and down to 3 in the most recent (partial) year — a flat-to-declining trajectory rather than a growth curve.
Water and wastewater treatment carries the field
C02F (564 records) and B01D (296) together account for the bulk of filings, confirming this is primarily a water-treatment and separation-engineering literature; C08F, C08L and C08J make up the underlying polymer-chemistry layer, with D21H (pulp and paper), C09K and C11D marking smaller application niches.
Shares are the percentage of the 812 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Water-Soluble Polymers and Flocculants with Eureka
This page is one run against one query. Ask Eureka your own question about water-soluble polymers and flocculants and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
Polymeric flocculant and method of sludge dehydration (US20030042209A1, Toagosei Co., Ltd.)
The invention provides a flocculant which in sludge dewatering gives flocs having an excellent balance among flocculating strength, filtration rate and moisture content, and a method of sludge dewatering with the flocculant. Namely, the flocculant is a polymeric flocculent which contains a copolymer having alkoxyalkyl units or a poly(alkylene oxide) unit and further having water-soluble monomer units; and the method of sludge dewatering includes adding the polymeric flocculant to a sludge after or without adding an inorganic flocculent or an organic cationic compound thereto and then dewatering the sludge.Filed by Toagosei Co., Ltd.; illustrates the alkoxyalkyl/poly(alkylene oxide) copolymer route to balancing flocculating strength against filtration rate in sludge dewatering.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | CN101327976A | 高效水处理絮凝剂 | 222 |
| 2 | EP0202780A2 | Flocculation processes | 154 |
| 3 | EP0657478A2 | An improved process for the preparation of water soluble polymer dispersion | 144 |
| 4 | US5837776A | Process for producing water soluble anionic dispersion polymers | 129 |
| 5 | US4720346A | Flocculation processes | 121 |
| 6 | US6426383B1 | Preparation of water soluble polymer dispersions from vinylamide monomers | 106 |
| 7 | US4880547A | Methods for water treatment | 102 |
| 8 | US5990216A | Method for manufacturing grafted polyacrylamide flocculant of cationic/ampholytic ions | 98 |
| 9 | US6447686B1 | Rapid coagulation-flocculation and sedimentation type waste water treatment method | 94 |
| 10 | EP0262945A2 | Water soluble polymeric compositions | 91 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside the searched corpus; treat this table as a map of historical influence, not current 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 say about where this field stands
Three findings that shape how a freedom-to-operate or whitespace search should be scoped in this area.
The core chemistry is largely staked out
Filings fell from a 2018 peak of 44 families to single digits by the most recent year, with the 2022 midpoint already down to 12. That trajectory, even adjusted for publication lag, suggests foundational flocculant and dewatering compositions are well covered and new activity is incremental.
Water treatment, not polymer science, drives filing volume
Nearly seven in ten records sit in C02F (water and wastewater treatment), with B01D separation processes second. Pure polymer chemistry (C08F, C08L, C08J) is present but secondary — most claims describe how a polymer is used in treatment, not novel polymer backbones.
Incumbents have stopped adding new claims
Every leading assignee tracked in the momentum data shows zero filings in the most recent year. That does not mean the field is abandoned — granted portfolios still block — but it does mean the largest players are not currently expanding claim scope here.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to water-soluble polymers and flocculants, with the prior art for and against each one.
Who holds the ground, and where the seams are
Filing has consolidated around a small set of industrial water-treatment and polymer specialists, several of which co-file through related corporate entities rather than a single name.
Corporate structure shows up as co-assignee pairs
The strongest co-assignee link in this dataset pairs two related Unilever entities on 23 shared families, with a third pairing to Conopco Inc. at 16 each. This is a corporate-structure signal, not evidence of joint R&D between unrelated firms.
Filing strategy leans US, Europe and China roughly evenly
United States (139), EPO (121) and China (95) are the three largest receiving offices, with Canada, WIPO/PCT and Australia forming a second tier. That spread points to a genuinely multi-jurisdictional filing strategy rather than a single home-market focus.
Named leaders are defending, not expanding
Specialty water-treatment and polymer names that recur across this dataset all register zero filings in the latest tracked year. Their historical volume still shapes freedom-to-operate risk, but a search for the newest activity in this space should look past the largest legacy names.
| Assignee | Recent year | YoY |
|---|---|---|
| Ciba Specialty Chemicals Water Treatments Ltd. | 0 | — |
| Allied Colloids Limited | 0 | — |
| BASF SE | 0 | — |
| Unilever N.V. | 0 | — |
| Nalco Company | 0 | — |
| Rohm and Haas Company | 0 | — |
| Calgon Corporation | 0 | — |
| Unilever PLC | 0 | — |
Turning this landscape into a filing or freedom-to-operate decision
The trend and rankings above describe the field as it stands; the next step is testing a specific claim or formulation against it.
Run a freedom-to-operate check on a specific formulation
The high-citation records here are decades old and still likely to be cited against new filings; a formulation-specific search will surface which of them actually reads on your chemistry.
Check claims in EurekaMap the under-claimed branches before drafting
Charge-density tuning and dissolution-rate control show thin coverage relative to core dewatering claims — worth confirming with a live search before assuming the space is open.
Explore whitespace in EurekaCommon questions about water-soluble polymer and flocculant patents
Filing in this space has historically concentrated among a handful of specialty water-treatment and polymer chemical companies, several of which file through related corporate entities that show up as co-assignee pairs in the data. However, every one of the leading assignees tracked in the momentum data shows zero filings in the most recent year, meaning their historical volume still matters for freedom-to-operate purposes but none of them is currently the most active filer. A search scoped to 'who is filing now' will look different from one scoped to 'who holds the most granted claims.'
No. Filings peaked at 44 families in 2018 and have declined in most years since, falling to 12 by the 2022 midpoint and to single digits in the most recent filed year. Publication lag of roughly eighteen months means the very latest year is always undercounted, but the multi-year downward trend predates that effect. This pattern is more consistent with a maturing field where core compositions are claimed and remaining activity is incremental.
The large majority sit in C02F, water and wastewater treatment, which accounts for 564 of 812 records, with B01D separation processes second at 296. Pure polymer chemistry under C08F, C08L and C08J is present but secondary, meaning most claims describe how a water-soluble polymer or flocculant is applied and dosed in a treatment or dewatering process rather than describing a novel polymer backbone. Smaller clusters in D21H, C09K and C11D mark niche applications in paper, specialty materials and detergents.
That filing, from Toagosei Co., Ltd., claims a polymeric flocculant built from a copolymer with alkoxyalkyl units or a poly(alkylene oxide) unit combined with water-soluble monomer units, used in a sludge dewatering method that adds the flocculant with or without an inorganic flocculant or organic cationic compound. Anyone working on copolymer flocculants that use alkoxyalkyl or poly(alkylene oxide) backbone units for sludge dewatering should check this claim scope directly against their own monomer composition and dosing sequence. It does not block flocculants built on unrelated backbone chemistries or applications outside sludge dewatering.
Relative to the dense coverage of core wastewater dewatering claims, narrower branches such as charge-density-tuned copolymer ratios, dissolution-rate-controlled granule coatings and settling-velocity optimisation additives appear thinly in this dataset. That thinness is a starting signal, not a guarantee of openness, so any filing decision should be checked against a live, claim-level search rather than the aggregate counts alone. The detergent-grade flocculant blend niche (C11D, 42 records) is similarly small and may be under-explored relative to the water-treatment core.
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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.