Nanofiltration Membrane Patents: Who Leads, Where the Gaps Are 2026
- Filings have cooled since the 2021 peak. 48 families filed that year against 20 at the 2022 midpoint and 10 so far in 2026, a partial-year figure that understates true filing activity given publication lag.
- China dominates the filing map. 182 records route through the China receiving office versus 102 in the United States and 53 at the EPO, signalling where enforcement and freedom-to-operate checks matter most.
- The technology reaches well beyond separation science. Beyond the core B01D filtration class, families cross into water treatment (C02F), metal extraction (C22B) and condensation polymers (C08G), pointing to reuse of NF chemistry across adjacent industries.
What this landscape covers
Nanofiltration sits between ultrafiltration and reverse osmosis, and the advanced-materials layer of that field is where most of the patenting activity concentrates: polyamide active layers, anti-fouling coatings, and charged nanofiltration materials built for selective ion or solute rejection. This dataset pulls 483 patent families published between 2015 and mid-2026 that combine nanofiltration search terms with material-specific claim language, filtered to the core separation-process IPC classes.
The picture is one of an established field rather than an emerging one: filing peaked in 2021 and has since declined toward the 2022 midpoint level, while citation weight still sits with membrane patents from the 1990s and 2000s. That combination — mature core claims, active peripheral filing — shapes where new entrants can realistically stake a position.
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Filing trends and technology composition
Two views of the same 483-family dataset: how filing volume has moved year over year, and which IPC subclasses the families also touch beyond the core separation-process classification.
A 2021 peak followed by decline
Annual filings rose from 31 in 2017 to a peak of 48 in 2021, then fell back to 20 by the 2022 midpoint and 10 in 2026 — a partial year that will revise upward as later publications land, given the roughly 18-month lag between filing and publication.
Concentrated in separation science, spilling into water treatment
All 483 records sit in B01D (separation processes), but 139 also touch C02F (water and wastewater treatment), and smaller but consistent counts appear in C22B (metal extraction), C08G (condensation polymers), C08L (polymer compositions), C08B (polysaccharides) and C08J (polymer processing) — evidence that NF material claims are being written to cover reuse in metal recovery and biopolymer-adjacent processing, not just water purification.
Shares are the percentage of the 483 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Nanofiltration Membrane Advanced Materials with Eureka
This page is one run against one query. Ask Eureka your own question about nanofiltration membrane advanced materials and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art carrying the most citation weight
US20180326362A1 — Highly selective alicyclic polyamide nanofiltration membrane and making method thereof
Filed by China University of Petroleum (East China), this filing discloses alternating coats of alicyclic acid chloride and alicyclic amine solutions on a porous support to build an alicyclic polyamide active layer, applied by spin coating or soaking. The stated advantage over conventional aromatic polyamide chemistry is improved divalent/monovalent selectivity — higher rejection of Ca2+ and Mg2+ alongside increased water flux and reduced fouling.Abstract condensed from the original filing text.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO1998015581A1 | Carbohydrate purification using ultrafiltration, reverse osmosis and nanofiltration | 136 |
| 2 | US5152901A | Polyamine-polyamide composite nanofiltration membrane for water softening | 131 |
| 3 | US20160038885A1 | High performance membranes for water reclamation using polymeric and nanomaterials | 111 |
| 4 | US20190344222A1 | An mxene based compositing nanofiltration membrane and corresponding preparation method | 76 |
| 5 | US7138058B2 | Acid stable membranes for nanofiltration | 63 |
| 6 | US20180326362A1 | Highly selective alicyclic polyamide nanofiltration membrane and making method thereof | 60 |
| 7 | CN101274222A | 一种动态自组装制备低压高通量荷电纳滤膜的方法 | 58 |
| 8 | US20100038306A1 | Asymmetric membranes for use in nanofiltration | 54 |
| 9 | US20050269265A1 | Carbohydrate purification using ultrafiltration, reverse osmosis and nanofiltration | 51 |
| 10 | US20030121857A1 | Acid stable membranes for nanofiltration | 50 |
Citation counts accumulate over time inside a fixed corpus, so older records are structurally favoured; treat this table as a map 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 a filing decision
Three patterns stand out once volume, geography and citation weight are read together.
China is the primary filing venue, not a secondary one
With 182 of 483 records routed through the China receiving office against 102 in the US and 53 at the EPO, freedom-to-operate work that stops at USPTO and EPO searches will miss the bulk of active claim scope in this field.
The core chemistry has stopped attracting new filings
Filing volume peaked in 2021 and has trended down since, including at every named top assignee, where recent-year new filings sit at zero. That does not mean the space is closed — it means the obvious polyamide and coating claims are already staked, pushing new work toward adjacent chemistries.
The foundational claims are decades old
The two most-cited records in this landscape date to 1992 and 1998, covering polyamine-polyamide composite membranes and carbohydrate purification by nanofiltration. Any polyamide active-layer claim written today has to be checked against this base layer of prior art first.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to nanofiltration membrane advanced materials, with the prior art for and against each one.
Who holds ground, and where the field is still open
Co-assignee pairings and recent filing behaviour point to a field where established membrane makers hold the centre and academic institutions supply a long tail of narrower claims.
LG's membrane and chemical units file together
The strongest co-assignee pairing in this dataset links an LG membrane entity with LG Chem at 18 shared filings, well ahead of the next pairings — a GE Osmonics cluster with named inventors at 5 filings each — indicating a tightly coordinated internal filing programme rather than opportunistic joint claims.
No single assignee is currently pushing volume
Every one of the most prominent assignees identified in this landscape — spanning Japanese, Korean, US and UK-linked entities — shows zero new filings in the latest year. That flattening is consistent with the broader post-2021 decline and suggests the next wave of activity, if it comes, will originate from newer or smaller filers.
Chinese universities and materials institutes fill the tail
A large share of the 483 families trace to Chinese university and provincial materials-institute assignees rather than multinational membrane makers, reflecting a research-driven filing pattern around specific active-layer chemistries and coating methods rather than platform-level IP.
| Assignee | Recent year | YoY |
|---|---|---|
| IP2IPO Innovations Limited | 0 | — |
| Toray Industries, Inc. | 0 | — |
| LG NanoH2O | 0 | — |
| GE Osmonics | 0 | — |
| LG Chem, Ltd. | 0 | — |
| Neos Technologies Inc. | 0 | — |
| Evonik Operations GmbH | 0 | — |
| Tiangong University | 0 | -100% |
Where to take this next
The trend and assignee data point to specific next steps depending on whether the goal is freedom-to-operate, licensing, or new filing strategy.
Check claims against the pre-2000 base layer
The two highest-cited records in this landscape predate 2000. Any polyamide or composite active-layer claim needs to be cleared against that foundational prior art before it is drafted, not after.
Explore prior art in EurekaPrioritise China filing and search coverage
With 182 of 483 records routed through China against 102 in the US, a freedom-to-operate review limited to US and EPO searches leaves the largest share of active claim scope unchecked.
Run a China-first FTO searchTarget the under-claimed branches
MXene-based composites, alicyclic polyamide chemistries and metal-recovery applications show thinner filing density than core polyamide and coating claims, and are the more realistic place to stake new claim scope.
Map white space in EurekaCommon questions on nanofiltration membrane patents
The dataset's strongest coordinated filer cluster links an LG membrane entity with LG Chem, which co-file at a notably higher rate than any other pairing in this landscape. Beyond that, filing is spread across Japanese, Korean, US and UK-linked corporate assignees alongside a large tail of Chinese university and materials-institute filers. None of the named top assignees show new filings in the most recent year, so leadership here reflects historical filing depth rather than current momentum.
Filings peaked at 48 in 2021 and have fallen toward 20 by 2022 and 10 by 2026, though the 2026 figure is a partial year understated by normal publication lag of around 18 months between filing and publication. The decline is consistent across the top assignees, each showing zero filings in the latest tracked year. This pattern typically means the core claim space — polyamide active layers, standard anti-fouling coatings — is already densely occupied, pushing new work toward adjacent or combination chemistries rather than the base technology.
The technology composition data shows filing density thinning out in branches like MXene-based composite active layers, alicyclic (non-aromatic) polyamide chemistries, and applications tied to metal recovery (C22B) or biopolymer-derived materials (C08B), relative to the dense core of aromatic polyamide and generic anti-fouling coating claims. A first claim in these areas would need to specify the material system precisely — for example, a named 2D material composite or a non-aromatic monomer pairing — rather than a broad polyamide-layer claim, which is likely to run into decades of existing prior art.
China accounts for 182 of the 483 records in this landscape, nearly double the US total of 102, with the EPO, Canada, WIPO and India following behind. Any freedom-to-operate or clearance search limited to US and European filings will miss the largest single block of active claims. For companies planning to manufacture or sell membrane materials in China, or sourcing components from Chinese suppliers, a China-specific search is not optional.
Citation counts in a fixed, searched corpus mechanically favour older patents because they have had more time to accumulate references — the two most-cited records here date to 1992 and 1998. That makes citation count a good signal of foundational influence on later claim drafting, but a poor signal of current commercial relevance. A newer, less-cited filing on a material like MXene composites can still represent the more active area of competitive interest.
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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.