Polysulfone Thermoplastics Patents: Leaders & Filing Trends 2026
- Filing has cooled since 2018. the peak year (69 records) gave way to a steady decline toward single digits by 2026, with the partial latest year understating true activity by roughly 18 months of publication lag.
- Separation processes dominate the claim map. B01D (filtration and membrane separation) accounts for 725 of the underlying records, well ahead of polymer composition claims under C08L.
- China now leads the receiving-office count. 353 filings at CNIPA edge out the United States (346) and the EPO (273), signalling where enforcement and freedom-to-operate checks matter most today.
Filing growth compares 2021 (47 records) with 2024 (66) — 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 1,524 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Polysulfone, polyethersulfone and related PSU resins sit at the intersection of two patent traditions: condensation polymer chemistry under C08G, and membrane and separation engineering under B01D. This dataset pulls 1,524 patent families filed between 2015 and 2026 that combine polysulfone-family search terms with claim language around membrane casting, hydrolytic stability, glass transition behaviour, solvent resistance and melt processing — the practical properties that decide whether a resin survives autoclaving, industrial filtration or high-temperature moulding.
The mix skews toward application engineering rather than raw monomer synthesis: separation-process claims (B01D) and polymer-composition claims (C08L) together outnumber core condensation-polymer chemistry (C08G), which suggests most recent filing effort goes into formulating and shaping existing PSU chemistry rather than inventing new backbone structures.
Filing trend and technology composition
Annual filing counts and IPC composition for the 1,524 families in this corpus, drawn directly from publication records.
A declining filing curve since 2018
Filings rose to a peak of 69 in 2018, held near the low 40s through the early 2020s, sat at 38 by the 2022 midpoint, and fell toward single digits by 2026. Because publication lags filing by around 18 months, the last one to two years will revise upward as more applications publish, but the multi-year downward slope through 2022-2024 predates that lag and reflects a genuine cooling in new filing activity.
Separation and composition claims dominate
B01D (separation processes, including membrane filtration) leads with 725 records, followed closely by C08L (polymer compositions, 681) and C08G (condensation polymers, 498). Processing-focused C08J (289) and additive-focused C08K (207) trail behind, with water-treatment-specific C02F (115), shaping process B29C (61) and addition-polymer C08F (61) forming a smaller tail — evidence that most invention activity clusters around how PSU resins are formulated and deployed in membranes rather than around alternative backbone chemistries.
Shares are the percentage of the 1,524 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Polysulfone and High-Performance Thermoplastics with Eureka
This page is one run against one query. Ask Eureka your own question about polysulfone and high-performance thermoplastics and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
US9127119B2 — Polycarbonate compositions having improved thermal dimensional stability and high refractive index
Disclosed herein are methods and compositions of polycarbonate compositions having, among other characteristics, improved thermal dimensional stability, hydrolytic stability and high refractive index. The resulting polycarbonate copolymer composition, comprising a polycarbonate and a polysulfone, can be used in the manufacture of articles for optical applications.Abstract reproduced from the filing; assignee and filing date are rendered separately.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6645412B2 | Process of making a three-dimensional object | 224 |
| 2 | US4602922A | Method of making membranes for gas separation and the composite membranes | 192 |
| 3 | JP1987121603A | Composite semipermeable membrane and preparation thereof | 158 |
| 4 | US5091480A | Comb-like polymers and graft copolymers from polyarylene polyether macromonomers | 122 |
| 5 | US4941893A | Gas separation by semi-permeable membranes | 99 |
| 6 | US4414269A | Solvent resistant polysulfone and polyethersulfone compositions | 99 |
| 7 | US5269931A | Cationic charge modified microporous membranes | 98 |
| 8 | US7300022B2 | Modified membranes | 93 |
| 9 | US5234990A | Polymers with intrinsic light-absorbing properties for anti-reflective coating applications in deep ultraviol… | 89 |
| 10 | US4690766A | Chemically modified semipermeable polysulfone membranes and their use in reverse osmosis and ultrafiltration | 89 |
Citation counts favour older filings simply because they have had more time to accumulate citations within the searched corpus; treat them as a marker of foundational influence, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns in this corpus matter more than the headline counts: where claims concentrate, where filing momentum has gone quiet, and where the geographic centre of gravity now sits.
The filing curve has flattened, not accelerated
From a 2018 peak of 69 records, annual filings declined through the 2022 midpoint of 38 and continued falling toward the most recent partial year. This is a maturing claim space rather than a growing one — new entrants face a denser prior-art baseline without a corresponding wave of fresh invention to design around.
Membrane and separation claims outweigh core chemistry
B01D leads the IPC composition, ahead of C08L polymer compositions and C08G condensation polymer chemistry. Filers have concentrated on membrane casting and separation performance rather than novel PSU backbone synthesis, meaning composition-of-matter opportunities may remain more open than membrane-application claims.
China has edged ahead as the leading receiving office
China's 353 filings now slightly exceed the United States (346) and clearly outpace the EPO (273), with Japan (217), the PCT route (93) and Canada (55) forming a smaller but active tail. Enforcement risk and competitive filing activity in this space are no longer US-centric.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to polysulfone and high-performance thermoplastics, with the prior art for and against each one.
Assignee landscape and collaboration patterns
Filing activity concentrates among a small set of established chemical and materials companies, several of which show no new filings in the most recent year — consistent with the corpus-wide slowdown rather than any single company's retreat.
Leading assignees show flat recent momentum
Several of the most active historical filers in this corpus, including major chemical and specialty-polymer producers, recorded no filings in the latest tracked year. Given the roughly 18-month publication lag, some of this reflects pending applications not yet published rather than an actual halt in R&D.
Co-filing is limited and mostly intra-group
Only ten co-assignee pairs appear in the corpus, and the strongest links look like affiliated entities under a shared corporate umbrella rather than arm's-length joint ventures. Cross-company collaboration is not a major feature of this landscape.
Receiving-office activity has shifted toward China
With China ahead of the US and EPO in raw filing counts, competitive and enforcement monitoring built only around USPTO and EPO records will miss a meaningful share of current activity in this field.
| Assignee | Recent year | YoY |
|---|---|---|
| Sumitomo Chemical Co., Ltd. | 0 | — |
| General Electric Company | 0 | — |
| Solvay Specialty Polymers USA, LLC | 0 | — |
| Solvay Advanced Polymers, L.L.C. | 0 | — |
| UOP LLC | 0 | — |
| Pall Corporation | 0 | — |
| BASF SE | 0 | — |
| Asahi Kasei Corporation | 0 | — |
Where to take this analysis
The dataset points to a maturing, membrane-heavy claim space with a shifted geographic centre. These next steps turn that into a working strategy.
Run a freedom-to-operate check on B01D membrane claims
With 725 records in separation processes, any new membrane-casting or filtration application should be checked against this subclass before development spend goes further.
Explore membrane claim density in EurekaMap the under-claimed additive and processing branches
C08K additive claims and B29C shaping-process claims sit well behind the corpus core, suggesting room for narrowly scoped filings that avoid the densest prior art.
Compare IPC branches in EurekaExtend geographic monitoring to CNIPA
China now leads the receiving-office count, ahead of the US and EPO, making a CNIPA-only blind spot in competitive monitoring increasingly costly.
Build a China-inclusive watch list in EurekaCommon questions about polysulfone and high-performance thermoplastics patents
Filing activity in this corpus concentrates among established specialty chemical and materials producers with long-running polymer businesses, several of which show no new filings in the most recent tracked year. Because publication lags filing by roughly 18 months, recent-year quiet does not necessarily mean these companies have stopped filing — some applications simply have not published yet. A practitioner assessing the competitive field should look at cumulative family counts and citation influence together, not just the latest single year.
No, not on the evidence here. Filings peaked at 69 in 2018, held near 38 by the 2022 midpoint, and have declined toward single digits by 2026. This pattern looks like a maturing claim space where the core chemistry and its main applications are already well covered, rather than an emerging area still attracting fresh invention. New filers should expect a denser prior-art baseline than the raw yearly counts might initially suggest given publication lag.
The IPC composition shows separation-process claims (B01D, 725 records) and polymer-composition claims (C08L, 681) far ahead of narrower branches like additive use (C08K, 207), plastics shaping (B29C, 61) and addition-polymer chemistry (C08F, 61). These thinner branches, particularly additive-modified blends and melt-shaping process claims, represent comparatively under-claimed territory relative to the dense membrane and composition core. That said, thinner filing density is not proof of easy patentability; it simply means less prior art to search against.
China leads the receiving-office count in this corpus with 353 filings, narrowly ahead of the United States at 346 and the European Patent Office at 273. Japan follows with 217, the PCT international route accounts for 93, and Canada has 55. Any competitive intelligence or clearance exercise limited to US and European sources alone would now miss the largest single jurisdiction by filing volume.
US9127119B2 covers polycarbonate compositions blended with polysulfone that achieve improved thermal dimensional stability, hydrolytic stability and high refractive index, aimed at optical-article manufacture. It is a composition-of-matter and application patent specific to that polycarbonate-polysulfone blend and its optical use, not a blocking claim over polysulfone chemistry generally. Formulations outside that specific blend ratio, property combination or optical application are unlikely to fall within its claims, but a full claim-by-claim comparison is needed before finalising any similar optical-grade blend.
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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.