Polyaluminium Chloride Patents: Top Companies & Trends 2026
- Concentrated but not locked up. the top 5 assignees hold 28.7% of all 341 records in scope, and the top 10 hold 43.1% — leaving well over half the field to a long tail of single- and few-filing entrants.
- Filing is still climbing, not cooling. 2021-to-2024 filings rose 43% (7 to 10), and the apparent post-2024 dip is a publication-lag artefact, not a real slowdown.
- Claims cluster hard on water treatment itself. 85.9% of records sit in C02F, but separation/filtration (B01D, 33.4%) and Al/rare-earth compound chemistry (C01F, 13.8%) are where secondary claim activity concentrates.
Filing growth compares 2021 (7 records) with 2024 (10) — 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 341 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Polyaluminium chloride (PAC) and related inorganic coagulants — including polyferric sulfate — sit at the intersection of inorganic chemistry and municipal or industrial water treatment. The dataset behind this page draws on 341 published patent families filed or published between 2015 and mid-2026, filtered on core coagulant terms alongside performance-specific language such as basicity ratio, turbidity removal, residual aluminium and low temperature performance — the phrases that separate genuine process and formulation claims from incidental mentions of coagulants in broader water treatment filings.
Because publication lags filing by roughly 18 months, the most recent one to two years in any trend understate real filing activity; 2024 is the last year that can be read as a complete picture.
Filing trend and technology composition
Two views of the same 341-record set: how filing volume has moved year over year, and how those records distribute across IPC subclasses.
Filing trend: steady growth, not a plateau
Filings rose from 10 in 2017 to a peak of 34 in 2020, and after settling lower, climbed again 43% from 2021 (7) to 2024 (10) — the most recent year with a reliable count. Treat 2025 and 2026 figures as still filling in rather than evidence of decline.
Technology composition: water treatment dominates, filtration and Al chemistry follow
C02F (water and wastewater treatment) covers 85.9% of the 341 records, confirming this is a treatment-process field first. B01D (separation and filtration, 33.4%) and C01F (Al and rare-earth compounds, 13.8%) are the two largest secondary clusters, with G01N (testing, 6.5%) and D21H (pulp and paper, 5.3%) marking smaller cross-industry pockets. Because records can carry multiple IPC codes, these shares sum to well over 100% of the record total.
Shares are the percentage of the 341 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Polyaluminium Chloride Coagulants with Eureka
This page is one run against one query. Ask Eureka your own question about polyaluminium chloride coagulants and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this field
Method of monitoring and optionally controlling removal of microplastics from microplastic containing waters
The filing describes using an optical measurement of light scattering and fluorescence to monitor microplastic particle counts before and after treatment with a coagulant and/or polymer, across raw water, drinking water, stormwater and various industrial and municipal effluent streams — tying coagulant dosing to a real-time contaminant-removal signal rather than a fixed recipe.Filed by Kemira, published 2025-08-26 — illustrates how established coagulant chemistry is being paired with newer measurement claims rather than replaced.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20080217244A1 | Water Treatment Method Comprising a Rapid Settling Step Followed by a Filtration Step Directly on Micro- or U… | 50 |
| 2 | US3617561A | Method for clarifying liquids | 38 |
| 3 | US3338828A | Purification of water supplies and aqueous wastes | 36 |
| 4 | EP0551061A1 | Process for the preparation of a coagulating chemical | 29 |
| 5 | US3388060A | Process and composition for purification of water supplies and aqueous wastes | 27 |
| 6 | JP1990290290A | Magnetic solid-liquid separation of waste water | 26 |
| 7 | US5531907A | Treatment of agricultural waste | 24 |
| 8 | WO2013098478A2 | Improving the efficiency of peracids | 22 |
| 9 | JP1990261505A | Method for controlling chemical injection in flocculating and settling device | 21 |
| 10 | JP1986257300A | Dehydrating method for sludge | 21 |
Citation counts reflect influence within the searched corpus and favour older filings; they are not a measure of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns worth acting on before drafting or clearing claims in this space.
Leadership is real but not exclusive
The top 5 assignees account for 28.7% of all 341 records, and the top 10 for 43.1% — a meaningful lead for the leader (39 records) but far short of a closed field. More than half of all filings sit with entities outside the ranked top 10.
Growth is real, not a spike
Filings rose from 7 in 2021 to 10 in 2024, a sustained three-year climb rather than a single-year jump. Treat any apparent fall after 2024 as a publication-lag effect, not a genuine cooling of interest.
Core treatment claims are dense; adjacent chemistry less so
C02F carries the overwhelming majority of filings, meaning core water-treatment process claims are heavily occupied. C01F (Al and rare-earth compound chemistry, 13.8%) and D21H (pulp and paper, 5.3%) carry far fewer filings relative to the core, suggesting these adjacent branches are comparatively open.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to polyaluminium chloride coagulants, with the prior art for and against each one.
Assignee landscape and where activity is shifting
The ranking covers 100 companies across the full 341-record set — not a top-50 or top-100 cut, but the entire ranked list the dataset returns.
One clear leader, a long tail behind it
The top-ranked assignee holds 39 of the 341 records, well ahead of fifth place (13) and tenth place (9). The gap between first and fifth is steep; the gap from fifth to tenth is much shallower, indicating a mid-tier cluster of similarly active filers.
Recent-year activity has gone quiet among incumbents
Several of the most historically active assignees, including established coagulant chemical suppliers, show zero filings in the latest year — a pattern consistent with publication lag rather than necessarily withdrawal, but worth tracking as records catch up.
Collaboration exists but is limited and concentrated
Only 10 co-assignee pairings appear across the dataset, the strongest linking a single multinational's regional entities and a legacy industrial filer with named individual inventors — suggesting most filings are single-assignee efforts rather than joint ventures.
| Assignee | Recent year | YoY |
|---|---|---|
| Kemira Oyj (Finland) | 0 | -100% |
| Organo Corporation | 0 | — |
| Laporte Industries Ltd. | 0 | — |
| Kemira Kemi AB | 0 | — |
| Sinvent AS | 0 | — |
| Unilever N.V. | 0 | — |
| Feralco AB | 0 | — |
| Unilever PLC | 0 | — |
Where to take this analysis
The landscape points to a field with clear leadership at the top and genuine openings beneath it. Turning that into a filing or clearance decision means going deeper than the aggregate numbers.
Map claims against the leader's portfolio
With one assignee holding 39 of 341 records, understanding exactly which claim elements it has locked down — and which it hasn't — determines whether a new filing needs to design around or can file alongside.
Explore assignee claims in Eureka →Test white-space branches for freedom to operate
Low-temperature performance, residual aluminium reduction and real-time dosing sensors show thinner filing density than the core C02F cluster — worth a focused prior-art pull before drafting.
Run a white-space search in Eureka →Common questions about this patent landscape
This dataset identifies 341 published patent families matching polyaluminium chloride, inorganic coagulant and polyferric sulfate terms combined with performance-specific language like basicity ratio, turbidity removal and residual aluminium. That figure covers filings from 2015 through mid-2026, though the most recent one to two years are undercounted because publication typically lags filing by around 18 months. It should be read as a bounded search-defined set rather than every patent ever filed on the topic.
One assignee leads clearly with 39 of the 341 records, well ahead of the fifth-place holder at 13. The top 5 assignees combined account for 28.7% of all records, and the top 10 combined account for 43.1%, meaning that even with a strong leader, more than half the field's filings sit outside the ten most active companies. This is a moderately concentrated field, not a single-company monopoly.
Filings grew 43% from 7 in 2021 to 10 in 2024, the last year with a reliable complete count. Numbers for 2025 and 2026 appear lower only because publications from those filing years are still working through the pipeline, not because underlying interest has dropped. A peak of 34 filings occurred in 2020, so activity has been uneven year to year but shows a genuine recovery through 2024.
The core cluster is C02F, water and wastewater treatment, covering 85.9% of the 341 records. Beyond that, separation and filtration processes (B01D) appear in 33.4% of records, aluminium and rare-earth compound chemistry (C01F) in 13.8%, and smaller clusters cover testing and analysis (G01N), catalysis-related processes (B01J) and pulp and paper applications (D21H). Because a single record can carry multiple IPC codes, these percentages add up to more than 100% of the record total.
Branches adjacent to the dense C02F core show comparatively thinner filing density, including low-temperature basicity control, residual aluminium reduction methods, real-time floc settling sensors, and dosing optimisation approaches. These sub-areas appear in the dataset's performance-language filters but don't dominate any single IPC subclass the way core treatment claims dominate C02F. A first claim in one of these areas would likely combine a specific measurement or control method with the coagulant chemistry, rather than claiming the chemistry alone.
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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.