RO Membrane Chlorine & Fouling Durability Patent Landscape
The RO membrane chlorine and fouling durability space comprises 142 patent families, led by Toray Industries with the largest single-applicant position; the field reached a peak in 2021 and annual volume has since eased, though several new entrants indicate that selective technical niches remain actively contested.
Toray leads a moderately concentrated field with a visible Japanese–Chinese competitive split
Toray Industries holds the top position among the hundred largest filers, followed closely by Teijin and Kurita Water Industries. The top five filers account for 24% of the hundred largest filers’ combined total, signalling moderate rather than extreme concentration.
A clear two-tier structure exists: Toray and Teijin sit noticeably ahead of the mid-pack, while a dense cluster from Kurita down to LG Chem holds positions three through ten with counts ranging from 18 to 10 patent records. Below that, the field disperses across a long tail of universities and smaller specialists.
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 1 | Toray Industries Inc | 27 | |
| 2 | Teijin Limited | 22 | |
| 3 | Kurita Water Industries Ltd | 18 | |
| 4 | Toyobo Co Ltd | 14 | |
| 5 | BEIJING RES INST OF CHEM IND CHINA PETROLEUM & CHE… | 14 | |
| 6 | CHINA PETROLEUM & CHEMICAL CORP | 14 | |
| 7 | Nitto Denko Corporation | 13 | |
| 8 | Wanhua Chemical Group Co Ltd | 12 | |
| 9 | Hunan Keensen Technology Co Ltd | 11 | |
| 10 | LG Chem Ltd | 10 |
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 11 | Shinshu University | 10 | |
| 12 | Korea Research Institute of Chemical Technology | 9 | |
| 13 | AGC Inc | 8 | |
| 14 | ROHM & HAAS CO | 8 | |
| 15 | The Dow Chemical Company | 8 | |
| 16 | The Research Foundation of State University of New York | 7 | |
| 17 | FilmTec Corporation | 7 | |
| 18 | Hydranautics | 6 | |
| 19 | Nanjing Shuibeizi Different Quantity Pipeline Water Co Ltd | 6 | |
| 20 | Midwest Research Institute | 6 |
The leaders’ positions reflect deep investment in membrane polymer chemistry and fabrication processes. Japanese incumbents (Toray, Teijin, Toyobo, Nitto Denko) collectively anchor the high end, while Chinese applicants—Sinopec’s Beijing Research Institute, Wanhua Chemical, and Hunan Keensen—signal an accelerating domestic effort to close the gap.
Filings from approximately 2024 onward are subject to publication lag and likely understate true recent activity; the 2026 count of zero reflects this lag rather than a cessation of R&D. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
A 2021 filing peak, a dominant separation-science core, and sparse adjacent branches
Annual filing volume and the IPC branch breakdown together reveal both the pace of the field and the technical areas attracting primary versus secondary investment.
Annual filing trend
Activity climbed from 7 filings in 2017 to a clear peak of 25 in 2021, then moderated to the lower teens by 2022–2023. The 2025 count of 23 appears elevated but should be read cautiously given publication lag on very recent applications; the 2026 figure of zero reflects that lag entirely.
↗ Hover for values · click a bar to ask EurekaTechnology composition
B01D (separation processes, including membrane fabrication and filtration) is overwhelmingly dominant, reflecting the core membrane-engineering focus. C02F (water and wastewater treatment) is the principal secondary branch, capturing system-level applications. Polymer chemistry branches—C08G and C08J—account for meaningful but smaller shares, pointing to materials-innovation work that underpins membrane durability improvements.
↗ 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.
PREPARATION METHOD OF FLUORINE-FREE Ti3C2Tx MXene-…
The present disclosure belongs to the technical field of composite membrane preparation, and discloses a preparation method of a fluorine-free Ti3C2Tx MXene-modified polyamide (PA) reverse osmosis (RO) membrane. The preparation method comprises: preparing a fluorine-free Ti3C2Tx MXene nanosheet material through etching with tetramethylammonium hydroxide… (excerpt from the patent abstract)
Open this patent in Eureka →| # | Patent | Citations |
|---|---|---|
| 1 | Interfacially synthesized reverse osmosis membrane | 1,163 |
| 2 | Reverse osmosis membrane | 237 |
| 3 | Interfacially synthesized reverse osmosis membrane | 173 |
| 4 | Semipermeable composite membrane | 159 |
| 5 | Semipermeable composite membrane | 122 |
| 6 | Method for preparation of semipermeable composite … | 116 |
| 7 | High flux high efficiency nanofiber membranes and … | 96 |
| 8 | Permselective membrane | 67 |
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—maturity, concentration, collaboration, and geography—together shape where entry barriers are high and where genuine white space persists.
Field is past its 2021 peak; consolidation phase underway
The lifecycle evidence places this field in decline, with annual filings easing back from the 2021 peak. Core polyamide thin-film composite chemistry is highly developed, so marginal incremental filings are harder to distinguish from background noise. R&D differentiation now likely requires addressing specific failure modes—chlorine-induced hydrolysis mechanisms or biofouling at the molecular level—rather than broad platform patents.
Lifecycle: DeclineModerate concentration leaves room for focused challengers
With the top five filers holding 24% of the hundred largest filers’ combined total, no single entity has locked up the space. The mid-tier cluster from rank 3 to 10 is tightly packed, meaning a well-targeted filing program in an underserved branch could move a challenger into the visible leadership tier. The long tail of university applicants also signals that academic IP may be available for licensing or partnership.
Moderate concentrationCo-filing is rare and concentrated within the Sinopec group
The most active co-filing pair is China Petroleum & Chemical Corp’s Beijing Chemical Research Institute filing jointly with its parent Sinopec entity, with 14 co-filed records—effectively an intra-group coordination rather than an arm’s-length partnership. Wanhua Chemical Group and its Ningbo subsidiary account for 2 co-filed records. Outside these two corporate families, cross-organization collaboration is not evidenced in the data, suggesting that IP alliances between independent parties remain largely untapped.
Limited cross-org IP alliancesChina is the primary prosecution venue; US, Europe, and Japan remain significant
China accounts for the largest share of patent records among all prosecution jurisdictions, reflecting both a growing domestic industry and a strategic push to secure rights in the world’s largest membrane-manufacturing base. The United States, Europe (EPO), and Japan each represent substantial secondary jurisdictions. South Korea and PCT filings round out a globe-spanning prosecution footprint, indicating that leading applicants treat this as a multi-market commercial asset.
China-led multi-jurisdictionalGo 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 |
|---|---|---|
| Sinopec Beijing Research Institute of Chemical Industry | China Petroleum & Chemical Corporation (Sinopec) | 14 |
| Wanhua Chemical Group Co Ltd | Wanhua Chemical (Ningbo) Co Ltd | 2 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
Toray anchors the field; Teijin and Kurita mount the strongest challenges
The two top-ranked applicants differ in their technology emphasis and trajectory, with Kurita emerging as a notable new entrant in recent periods.
Toray Industries
Toray holds the top position with 27 patent records and concentrates its work firmly in B01D membrane separation sub-classes—specifically B01D71 (membrane materials), B01D69 (membrane structures), and B01D61 (membrane processes). This breadth across fabrication, structure, and application sub-classes reflects a platform-level strategy rather than a single product niche. Momentum data does not flag Toray as a new entrant, consistent with a long-established and sustained filing program.
patent records: 27Kurita Water Industries
Kurita ranks third with 18 patent records and is flagged as a new entrant in recent filings, with 6 recent records. Its technical emphasis leans toward B01D65 (membrane maintenance and cleaning) alongside the broader B01D71 and B01D61 sub-classes, suggesting a differentiated focus on operational durability and membrane-system management rather than pure polymer synthesis. This operational angle may reflect Kurita’s water-treatment services background and could position it to capture IP in cleaning chemistry and fouling-mitigation protocols.
patent records: 18| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| Kurita Water Industries Ltd | 6 | ▲ new entrant |
| Nitto Denko Corporation | 1 | ▲ new entrant |
| Wanhua Chemical Group Co Ltd | 6 | ▲ new entrant |
| Hunan Keensen Technology Co Ltd | 5 | ▲ new entrant |
Under-served IPC branches adjacent to the dominant separation-science core
Several IPC branches appear in the corpus at low frequency relative to the dominant B01D class, representing areas where patent density is thin. Each is noted as an observation of relative sparsity; technical and commercial merit should be assessed independently.
C11D · Detergents & cleaning compositions
With only 11 patent records and a 2% share among the hundred largest filers’ activity, C11D is sparsely covered despite the direct relevance of cleaning-chemistry formulations to fouling removal and membrane restoration cycles. Applicants active in membrane operation (such as Kurita, with its maintenance-oriented B01D65 focus) are plausible entry points, and the branch sits adjacent to existing water-treatment expertise. The sparse coverage may reflect that cleaning chemistries are developed by detergent companies outside the core membrane IP community, leaving a gap for membrane specialists to claim.
Search this in Eureka →B05D · Coating processes
B05D accounts for only 9 patent records and a 1% share, suggesting that surface-coating methods applied to membranes for chlorine resistance or anti-biofouling purposes are not yet heavily patented within this corpus. Given that thin protective coatings are a known strategy for extending membrane life against oxidant exposure, the sparse filing count indicates that coating-process IP may be underdeveloped relative to its technical importance. Applicants with polymer-chemistry capabilities (active in C08G or C08J) would have a plausible path into this branch.
Search this in Eureka →How leaders differ by IPC technology route
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 |
|---|---|---|---|---|---|
| Toray Industries Inc | Strong · 23 | Strong · 16 | Absent | Strong · 14 | Moderate · 6 |
| China Petroleum & Chemical Corporation (Sinopec) | Strong · 14 | Strong · 11 | Strong · 14 | Moderate · 6 | Strong · 10 |
| Sinopec Beijing Research Institute of Chemical Industry | Strong · 14 | Strong · 11 | Strong · 14 | Moderate · 6 | Strong · 10 |
| Wanhua Chemical Group Co Ltd | Strong · 10 | Absent | Strong · 11 | Strong · 8 | Strong · 11 |
| Teijin Limited | Strong · 22 | Strong · 15 | Absent | Absent | Absent |
| Kurita Water Industries Ltd | Strong · 14 | Absent | Absent | Strong · 12 | Moderate · 6 |
| Nitto Denko Corporation | Strong · 13 | Strong · 9 | Strong · 9 | Absent | Absent |
Frequently asked questions
The landscape comprises 142 patent families in scope. These are distributed across multiple prosecution jurisdictions, with China accounting for the largest single-office count of patent records.
Toray Industries holds the top position with 27 patent records, ahead of Teijin with 22 and Kurita Water Industries with 18. Toray’s filings span membrane materials, structures, and process sub-classes within B01D.
Annual filings peaked in 2021 at 25 and have since eased back. The lifecycle stage is assessed as decline based on this easing from the peak. Filings from 2024 onward are subject to publication lag and may understate true current activity.
China is the leading prosecution office with 124 patent records, well ahead of the United States at 63, Europe (EPO) at 57, and Japan at 51. This reflects both China’s large domestic membrane manufacturing base and its strategic importance as a commercial market.
The only substantive co-filing relationship evidenced is between China Petroleum & Chemical Corp (Sinopec) and its Beijing Chemical Research Institute, which jointly filed 14 records—an intra-group arrangement. Wanhua Chemical Group and its Ningbo subsidiary co-filed 2 records. Independent cross-organization IP alliances are not evidenced in the data.
C11D (detergents and cleaning compositions) and B05D (coating processes) each appear at low frequency—11 and 9 patent records respectively—relative to the dominant B01D separation-processes branch. C08G (condensation polymers) and C08J (polymer processing) are also secondary branches with 53 and 36 records, representing more active but still secondary coverage compared with B01D’s 388 records.
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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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