Polyimide Curing Process Patents: Top Companies & Trends 2026
- Filing has cooled since its 2017 peak. 157 filings that year against 19 in the most recent (partial) year, with the 2022 midpoint at 131 — a declining trend, not a growing one.
- China and the US dominate the filing map. 704 records route through the Chinese receiving office and 631 through the US, more than double the EPO's 384 and far ahead of Japan's 95.
- Claim density concentrates in composition, not process alone. C08G condensation-polymer claims cover 1,867 of 2,118 records, meaning most cure-schedule claims are anchored to specific monomer or additive chemistry rather than filed as standalone process claims.
Filing growth compares 2021 (69 records) with 2024 (96) — 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 2,118 records in scope (CR5), not by the ranked leaders only.
What the polyimide curing process patent record shows
Polyimide curing — the thermal imidization step that converts a cast polyamic acid film into a stable polyimide — sits at the intersection of process engineering and materials chemistry. The 2,118 patent families captured here span everything from cure-schedule and cyclization-curing claims to the additive packages and substrates that curing is optimized around. Because the search anchors on thermal imidization, cure schedule, cyclization curing and cure kinetics language inside condensation-polymer, polymer-processing and polymer-composition IPC codes, the corpus reflects filings that treat the cure step itself as inventive territory, not just polyimide chemistry generally.
Filing activity peaked in 2017 and has trended down since, with the 2022 midpoint still below that peak. Because publication typically lags filing by around 18 months, the most recent year understates real activity — but the multi-year decline from the 2017 high is a pattern, not a single-year dip.
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Filing trend and technology composition
Two views of the same 2,118-family corpus: how filing volume has moved year over year, and which IPC subclasses carry the claim weight.
A 2017 peak followed by a multi-year decline
157 filings in 2017 fell to a 2022 midpoint of 131 and to 19 in the most recent partial year. Read the tail end cautiously — publication lag means the last one to two years will always look thinner than they eventually turn out to be — but the trajectory from peak to midpoint is already a decline, not noise.
Composition claims outweigh pure process claims
C08G (condensation polymers) touches 1,867 of 2,118 records and C08L (polymer compositions) another 1,031, against 967 for C08J (polymer processing) — evidence that most cure-related claims are filed alongside specific chemistry rather than as generic process protection. Downstream application codes (H01L semiconductor devices, B32B laminates, H05K printed circuits) each sit well below 200, marking them as adjacent rather than core filing territory.
Shares are the percentage of the 2,118 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Polyimide Curing Process with Eureka
This page is one run against one query. Ask Eureka your own question about polyimide curing process and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records anchoring this space
US20210040279A1 — Method of preparing polyimide film and display panel
Filed by Shenzhen China Star Optoelectronics Semiconductor Display Technology, this record describes dissolving an aromatic diamine monomer in solvent, adding a silane coupling agent, then a dianhydride monomer to form a polyamic acid solution; coating it on a glass substrate; drying; and carrying out thermal imidization under vacuum before natural cooling. The stated aim is to enhance adhesion between the polyimide film and its substrate and reduce substrate separation from poor adhesion.Published 2021-02-11 — a display-panel-specific cure route worth checking against for adhesion-focused claims.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5406124A | Insulating adhesive tape, and lead frame and semiconductor device employing the tape | 324 |
| 2 | US6232428B1 | Essentially colorless, transparent polyimide coatings and films | 207 |
| 3 | CN101831175A | 一种无色透明的聚酰亚胺纳米复合材料膜及其制备方法 | 138 |
| 4 | WO2018117239A1 | Method for producing liquid crystal alignment film, liquid crystal alignment film, and liquid crystal display… | 124 |
| 5 | US5194928A | Passivation of metal in metal/polyimide structure | 103 |
| 6 | JP2012035583A | Method of manufacturing laminate, and flexible device | 95 |
| 7 | JP1986264028A | Polyimide film having high dimensional stability and production thereof | 94 |
| 8 | US4895972A | Process for lowering the dielectric constant of polyimides using diamic acid additives | 92 |
| 9 | US5218077A | Diphenylmethane-containing dianhydride and polyimides prepared therefrom | 76 |
| 10 | CN105461923A | 一种聚酰亚胺薄膜及其制备方法 | 75 |
Citation counts favour older filings simply because they've had more time to accumulate cites within this searched corpus — treat them as a signal of influence on later filers, not as a ranking of current commercial importance.
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 data means for filing and freedom-to-operate decisions
Three read-throughs from the filing trend, jurisdiction split and citation pattern.
The core cure-schedule space is past its filing peak
A decline from 157 filings in 2017 to a 2022 midpoint of 131 signals that the foundational thermal-imidization and cure-kinetics claim space has already been substantially staked out. New entrants are more likely to find open ground in adjacent application claims than in the core cure step itself.
China and the US are the two gatekeeper jurisdictions
With 704 records routed through China and 631 through the US — well ahead of EPO's 384, Japan's 95 and WIPO's 73 — any freedom-to-operate check on cure-schedule claims has to start with Chinese and US prior art before looking elsewhere.
Cure claims rarely stand alone
C08G's near-total coverage of the corpus (1,867 of 2,118) shows that curing-process claims are almost always tied to specific condensation chemistry. A cure-schedule claim filed in isolation, without tying it to a monomer or additive system, is the exception rather than the rule.
Collaboration is thin and concentrated in one pairing
Only 10 co-assignee pairs appear in the dataset, and the strongest — Donghua University with Shanghai Ruitu Electronic Materials Co., Ltd. at 36 shared filings — dwarfs the next pairings, which sit in single digits. Most assignees in this space file independently.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to polyimide curing process, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Donghua University | Shanghai Ruitu Electronic Materials Co., Ltd. | 36 |
| Kaneka Corporation (Taiwan) | Kaneka Corporation | 6 |
| Kaneka Corporation (Taiwan) | Japan Aerospace Exploration Agency (JAXA) | 4 |
| Kolon Industries, Inc. | JUNG HAK GEE | 3 |
| UBE Corporation | Iwate University | 2 |
| Kolon Industries, Inc. | PARK SANG WOOK | 2 |
| Kolon Industries, Inc. | PARK HYO JUN | 2 |
| UBE Corporation | University of Tsukuba | 1 |
The Donghua University / Shanghai Ruitu Electronic Materials Co., Ltd. pairing (36 shared filings) is the clear outlier against a field where most co-filing pairs sit at single-digit counts.
Who is active, and where the momentum has gone quiet
The assignee list is a long tail rather than a two- or three-way race. Recent-year momentum figures are worth reading carefully: several previously active filers show zero filings in the latest year, though publication lag means that number will firm up as later filings publish.
Even the most recently active filer has slowed sharply
Donghua University shows just 1 filing in the latest year with 0% YoY movement — the single assignee still showing any latest-year activity among the names tracked here, and even that is flat rather than growing.
Several established filers have gone dark on new filings
Mitsui Chemicals, Inc., LG Chem, Ltd., Kaneka Corporation (Taiwan), UBE Corporation and Kolon Industries, Inc. all show zero filings in the latest year. That is consistent with the broader decline from the 2017 peak, though publication lag means some of this will still resolve upward.
One university-industry pairing stands apart
Donghua University's pairing with Shanghai Ruitu Electronic Materials Co., Ltd. at 36 shared filings is the strongest link in a dataset of only 10 recorded co-assignee pairs, most of which involve legacy Japanese chemical firms filing jointly across related entities.
| Assignee | Recent year | YoY |
|---|---|---|
| Donghua University | 1 | 0% |
| Mitsui Chemicals, Inc. | 0 | — |
| LG Chem, Ltd. | 0 | — |
| Kaneka Corporation (Taiwan) | 0 | — |
| UBE Corporation | 0 | — |
| Kolon Industries, Inc. | 0 | — |
| Fujifilm Electronic Materials U.S.A., Inc. | 0 | — |
| Chang Chun Plastics Co., Ltd. | 0 | — |
Where to take this analysis
The trend and assignee data point to a mature core and a thinner periphery. Two directions follow from that.
Map claims against your own process parameters
Run your specific cure-schedule temperatures, ramp rates and additive systems against the C08G-heavy cluster before assuming a process-only claim is clear — most granted claims here are chemistry-anchored.
Explore in Patsnap Eureka →Watch the application-layer codes, not just the core
H01L, B32B and H05K sit well below the core IPC codes in volume, suggesting downstream application claims (semiconductor packaging, laminates, printed circuits) are less contested than the base cure chemistry.
Explore in Patsnap Eureka →Common questions about polyimide curing process patents
In this dataset, it means a filing whose title or claims reference thermal imidization, cure schedule, cyclization curing, or cure kinetics, classified under IPC codes covering condensation polymers (C08G73/10), polymer processing (C08J5/24) or polyimide compositions (C08L79/08). Most of these are not pure process patents — they tie the cure step to a specific monomer, additive or substrate system. That means a freedom-to-operate check needs to look at the surrounding chemistry claims, not just the temperature ramp or atmosphere conditions described in the process steps.
No — filings peaked at 157 in 2017 and had fallen to a 2022 midpoint of 131, with only 19 recorded in the most recent partial year. That is a declining trend across the tracked period, not a plateau. Publication lag of roughly 18 months means the last one to two years will always look artificially thin, but the multi-year drop from the 2017 peak predates that lag effect and reflects a real slowdown in new core filings.
China and the United States are the two dominant receiving offices, with 704 and 631 records respectively — together more than double the EPO's 384. Japan (95), WIPO/PCT (73) and Canada (34) are meaningfully smaller. Any clearance search or competitive monitoring program in this space should prioritize Chinese and US patent databases first, then extend to EPO filings, since Japan-originated filings are a smaller share than the historical prominence of Japanese polyimide chemistry firms might suggest.
Activity has slowed markedly among several previously prominent filers — Mitsui Chemicals, Inc., LG Chem, Ltd., Kaneka Corporation (Taiwan), UBE Corporation and Kolon Industries, Inc. all show zero filings in the latest tracked year. Donghua University is the one name in the tracked set still showing any latest-year activity, though at just one filing with flat year-over-year movement. This pattern is consistent with the broader filing decline from the 2017 peak, though later-publishing filings could still shift the most recent year's numbers upward.
The core cure-schedule and cyclization-curing claims tied to specific monomer chemistry are densely filed, reflected in C08G's coverage of 1,867 of 2,118 records. Thinner ground sits in process-only cure-schedule claims decoupled from a named chemistry system, and in adjacent application layers like printed-circuit polyimide (H05K, 150 records) and semiconductor packaging (H01L, 157 records), which are far less contested than the base chemistry. Low-temperature cure schedules aimed at flexible display substrates and cure kinetics for low-CTE polyimide/metal laminates are two specific branches worth checking before assuming the space is closed.
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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.