RO Membrane Surface Engineering Patent Landscape
RO membrane surface engineering is an active, growing field anchored by a small group of established membrane manufacturers — Nitto Denko, LG Chem, and their affiliated entities — holding a commanding combined share of the top-ranked filers. Filing activity is still rising on a multi-year basis, with China the dominant jurisdiction for prosecution and separation-process chemistry (B01D) accounting for the vast majority of technical activity.
Nitto Denko and LG Chem lead a moderately concentrated field
Nitto Denko Corp holds the top-ranked position among the hundred largest filers, followed closely by LG Chem. The top five filers together account for 24% of the combined patent records of the hundred largest filers, signaling moderate concentration with meaningful room for challengers.
The tier gap between the top two applicants (78 and 76 patent records respectively) and the third and fourth (55 each) is relatively narrow, indicating competitive parity across the leading group rather than a single dominant incumbent. Beyond the top ten, activity fragments across Chinese universities and domestic manufacturers.
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 1 | Nitto Denko Corporation | 78 | |
| 2 | LG Chem Ltd | 76 | |
| 3 | NanoH2O Inc | 55 | |
| 4 | Toray Advanced Materials Korea Inc | 55 | |
| 5 | EI DU PONT DE NEMOURS & CO | 54 | |
| 6 | Hydranautics | 46 | |
| 7 | Saehan Industries Co Ltd | 46 | |
| 8 | NanoH2O Co Ltd | 46 | |
| 9 | Dow Global Technologies LLC | 43 | |
| 10 | LG NanoH2O Inc | 43 |
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 11 | The Dow Chemical Company | 40 | |
| 12 | Zhejiang University of Technology | 35 | |
| 13 | Vontron Technology Co Ltd | 27 | |
| 14 | FilmTec Corporation | 26 | |
| 15 | Wanhua Chemical Group Co Ltd | 22 | |
| 16 | Tianjin Polytechnic University | 19 | |
| 17 | Hunan Keensen Technology Co Ltd | 19 | |
| 18 | Tianjin University | 19 | |
| 19 | BL Technology Inc | 18 | |
| 20 | Zhejiang University | 16 |
The leaders’ positions reflect deep, sustained programs in polyamide thin-film composite membrane chemistry. Their breadth across B01D subclasses — membrane materials, configurations, and process operations — suggests they have built interlocking portfolios that create meaningful freedom-to-operate barriers for late entrants targeting mainstream polyamide chemistry.
Filing counts for 2025 and 2026 are materially understated due to the 18–24 month patent publication lag and should not be read as a slowdown. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
Annual filings are rising and separation-process chemistry dominates the mix
The trend chart captures yearly filing volume from 2017 through 2026, while the technology-composition chart shows how activity is distributed across IPC classes. Together they reveal a field with rising output concentrated almost entirely in filtration and polymer chemistry.
Annual filing trend
Filings held in the 61–65 range from 2017 to 2019, dipped in 2020, then recovered through 2021–2024 and reached 81 records in 2024. The 2025 figure (98 records) and the 2026 figure (15 records) are heavily understated by publication lag and should be treated as floors, not peaks. On a multi-year basis the field is still expanding, consistent with a 10% recent growth rate.
↗ Hover for values · click a bar to ask EurekaTechnology composition
B01D (separation processes including filtration) overwhelmingly dominates the IPC mix, followed distantly by C02F (water and wastewater treatment) and C08G (condensation polymers). The long tail of lower-share classes — B05D (coating processes), B01J (chemical and physical processes), C07C (acyclic compounds) — represents adjacent technical territory with comparatively sparse coverage, pointing to potential areas where differentiated approaches could find room.
↗ Hover for values · click a bar to ask EurekaHighly cited patent families surfaced by the query
Citation-heavy patent families returned by the query. Use this section as citation context, not as a curated list of the most topic-specific patents.
Seawater desalination reverse osmosis membrane wit…
A method for creating a seawater desalination reverse osmosis membrane that excels in both water flux and boron removal. The method utilizes the abundant and reactive amino groups of carbon nitride in an interfacial polymerization reaction to enhance the membrane’s structure. The unique pore and interlayer structure of carbon nitride is employed to modify… (excerpt from the patent abstract)
Open this patent in Eureka →| # | Patent | Citations |
|---|---|---|
| 1 | Interfacially synthesized reverse osmosis membrane | 1,162 |
| 2 | Composite membrane and method for making the same | 324 |
| 3 | Composite membrane and method for making the same | 279 |
| 4 | Reverse osmosis membrane | 237 |
| 5 | Novel polyamide reverse osmosis membranes | 233 |
| 6 | Highly permeable composite reverse osmosis membran… | 221 |
| 7 | Interfacially synthesized reverse osmosis membrane… | 219 |
| 8 | Polyamide membranes useful for water softening | 219 |
Ranked by total forward citations. Citation counts favour older and broadly cited patent families, and broad or adjacent patents may appear when they match the search scope. Treat this section as citation context, not as a curated list of the most topic-specific patents. Some patent titles may be shown in their original, non-English language where an accurate translation could not be guaranteed.
What the competitive structure means for R&D investment decisions
Four structural dimensions — lifecycle stage, concentration, collaboration patterns, and geographic reach — frame how new entrants and existing players should position their RO membrane surface engineering programs.
Growth stage with rising annual volume
The lifecycle evidence classifies this field as Growth, with annual filings still rising and the most recent years understated by publication lag. A 10% recent growth rate confirms the field has not yet entered a consolidation or maturity plateau. R&D investment can still establish meaningful positions, though core polyamide chemistry is heavily covered by the leading incumbents.
Lifecycle: GrowthModerate concentration with a competitive top tier
The top five filers hold 24% of combined patent records among the hundred largest filers, and the gap between the first and fifth ranked applicants is modest. This structure means no single player has locked up the field, but the leading cluster — Nitto Denko, LG Chem, NanoH2O, Toray Advanced Materials Korea, and DuPont — has deep, overlapping coverage of mainstream membrane separation subclasses. Differentiation through adjacent chemistry or novel surface modification routes is a more viable entry path than direct competition on core polyamide formulations.
Moderate concentrationLG Chem–LG NanoH2O and Nitto–Hydranautics are the most active co-filer pairs
The strongest co-filing relationship in the evidence is between LG Chem and LG NanoH2O, with 21 jointly filed patent records, reflecting the integration of NanoH2O’s nanocomposite membrane technology into LG Chem’s portfolio. Nitto Denko and Hydranautics follow with 15 co-filed records, and Dow Chemical and FilmTec account for 10, again reflecting corporate family ties. LG Chem and Korea University Research and Business Foundation have 6 co-filed records, the only significant industry–academic pairing in the evidence.
Corporate ecosystemChina is the primary prosecution jurisdiction; the US and EPO provide broad international coverage
China accounts for the largest number of patent records in the dataset, followed by the United States and EPO. South Korea and WIPO (PCT) also carry significant volumes, reflecting the Korean origins of several leading applicants. Japan, Canada, and Australia round out meaningful secondary markets. Emerging-market jurisdictions such as India, Israel, and Singapore have modest but non-trivial coverage, suggesting selective international filing strategies focused on key desalination and water-treatment markets.
China-led, global spreadGo beyond the landscape: Eureka’s TRIZ Solution agent breaks down an R&D problem and returns patented concept solutions, each with a technical approach and cited patent & literature evidence.
| Applicant | Collaborator | Co-filings |
|---|---|---|
| LG Chem Ltd | LG NanoH2O Inc | 21 |
| Nitto Denko Corporation | Hydranautics | 15 |
| The Dow Chemical Company | FilmTec Corporation | 10 |
| LG Chem Ltd | Korea University Research and Business Foundation | 6 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
Nitto Denko and LG Chem lead through deep B01D coverage and affiliated-entity portfolios
Both top-ranked applicants concentrate their technology focus entirely within B01D separation-process subclasses — membrane materials (B01D71), membrane configurations (B01D69), and membrane operations (B01D61/B01D67) — making them direct strategic competitors across the full surface engineering workflow.
Nitto Denko Corporation
Nitto Denko holds the top-ranked position with 78 patent records. Its technology focus spans membrane configurations (B01D69, 65 records), membrane materials (B01D71, 58 records), and membrane manufacturing processes (B01D67, 38 records), indicating full-stack coverage from polymer selection through fabrication. Its affiliated entity Hydranautics contributes an additional 46 patent records with a parallel B01D focus and 15 co-filed records, substantially amplifying Nitto’s effective portfolio footprint. Momentum data flags Nitto Denko as a new entrant in the most recent period — likely reflecting a reorganization or entity reclassification rather than a genuinely new market presence.
78 patent recordsLG Chem Ltd
LG Chem ranks second with 76 patent records and holds the heaviest weighting in B01D71 (membrane materials, 106 records across its own filings), followed by B01D69 (96 records) and B01D61 (84 records). When its affiliated entities LG NanoH2O (43 records) and the historical NanoH2O Inc (55 records) and NanoH2O Co Ltd (46 records) are considered alongside its 21 co-filed records with LG NanoH2O, LG Chem’s combined ecosystem represents the field’s largest coordinated portfolio. Its nanocomposite membrane lineage — acquired through NanoH2O — gives it a distinct technical identity within the mainstream polyamide surface engineering space.
76 patent records| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| Nitto Denko Corporation | 1 | ▲ new entrant |
Under-served branches in polymer processing and coating technology
Several IPC classes sit adjacent to the dominant B01D core but carry comparatively sparse patent coverage. These branches are observations of relative sparsity; only those with plausible technical value and a realistic entry path are framed as potential opportunities.
B05D · Coating processes
With only 33 patent records against more than 1,500 in B01D, coating process methodology is notably sparse relative to the volume of surface modification claimed in the dominant class. Surface grafting, layer-by-layer deposition, and atmospheric plasma coating for fouling resistance are established laboratory techniques with commercial relevance, yet the patent record in B05D for RO membrane contexts is thin. An entrant with process-equipment or surface-chemistry expertise could establish differentiated positions in controlled thin-film deposition routes without directly colliding with the incumbent polyamide formulation portfolios.
Search this in Eureka →C08J · Polymer processing and solutions
C08J carries 102 patent records — a secondary volume relative to B01D but modest for a class directly relevant to membrane casting, crosslinking control, and solvent-exchange processing. As fabrication precision becomes a performance differentiator, the chemistry of polymer solution preparation and post-treatment processing represents an under-documented technical axis. Academic filers such as Zhejiang University of Technology and Tianjin University are active in polymer membrane formulation, suggesting that industry players willing to collaborate with academic groups could accelerate position-building in this branch.
Search this in Eureka →How leading applicants differ across B01D membrane subclasses
Route coverage across the main technology branches in the current evidence set.
| Player | B01D 71 · Separation processes (filtration etc.) | B01D 69 · Separation processes (filtration etc.) | B01D 67 · Separation processes (filtration etc.) | B01D 61 · Separation processes (filtration etc.) | C02F 1 · Water & wastewater treatment |
|---|---|---|---|---|---|
| LG Chem Ltd | Strong · 106 | Strong · 96 | Moderate · 46 | Strong · 84 | Moderate · 36 |
| Nitto Denko Corporation | Strong · 58 | Strong · 65 | Strong · 38 | Strong · 34 | Moderate · 17 |
| NanoH2O Inc | Strong · 52 | Strong · 37 | Moderate · 20 | Strong · 34 | Absent |
| Saehan Industries Co Ltd | Strong · 48 | Strong · 45 | Moderate · 21 | Moderate · 15 | Moderate · 12 |
| Zhejiang University of Technology | Strong · 32 | Strong · 30 | Strong · 34 | Strong · 30 | Moderate · 15 |
| E I du Pont de Nemours and Company | Strong · 49 | Strong · 42 | Absent | Moderate · 24 | Absent |
| Hydranautics | Strong · 41 | Strong · 37 | Moderate · 17 | Absent | Moderate · 15 |
Frequently asked questions
The evidence covers 627 patent families in scope for this topic. This corpus underpins all applicant rankings, trend analysis, and technology composition figures in the landscape.
Nitto Denko Corporation holds the top-ranked position with 78 patent records among the hundred largest filers, followed closely by LG Chem with 76 patent records. When affiliated entities are included, the LG Chem ecosystem (LG NanoH2O, NanoH2O Inc, NanoH2O Co Ltd) represents the field’s largest coordinated group.
Yes. The lifecycle evidence classifies the field as Growth, supported by a 10% recent growth rate and annual filing volumes that have risen on a multi-year basis. The 2025 and 2026 figures in the trend data are materially understated by the patent publication lag and should not be interpreted as a slowdown.
China is the lead prosecution jurisdiction, with the largest number of patent records in the dataset. The United States and the EPO follow as the primary international filing destinations, with South Korea and WIPO (PCT) also carrying significant volumes reflecting the Korean origins of several leading applicants.
B01D (separation processes, including filtration) is overwhelmingly dominant, followed distantly by C02F (water and wastewater treatment) and C08G (condensation polymers). The long tail of adjacent classes — including C08J (polymer processing), B05D (coating processes), and C07C (acyclic compounds) — carries comparatively sparse coverage relative to B01D.
The strongest co-filing relationship is between LG Chem and LG NanoH2O, with 21 jointly filed patent records reflecting the integration of nanocomposite membrane technology. Nitto Denko and Hydranautics have 15 co-filed records. Dow Chemical and FilmTec account for 10, and LG Chem and Korea University Research and Business Foundation have 6 — the primary industry–academic pairing in the evidence.
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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.
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