Photoinitiator Systems Patents: Who Leads, Where the Gaps Are 2026
- 76.1% of the field sits with five assignees. 150 of 197 records in scope belong to the top five, and the leader alone holds 51 — this is a concentrated field, not a fragmented one.
- Filing has gone quiet since the 2018 peak of 36. The tracked 2021→2024 span shows a full -100% drop to zero, though 2025-2026 counts are still filling in under normal publication lag.
- C08F and A61K dominate, G03F is close behind. 64.5% of records touch addition polymer chemistry and 58.4% touch medicinal preparations — dental and photolithography use cases overlap heavily here.
Filing growth compares 2021 (2 records) with 2024 (0) — 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 197 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks 197 patent families published between 2015 and mid-2026 that combine photoinitiator system claims with migration-related technical concerns: absorption spectrum matching, oxygen inhibition, yellowing, extractables, food contact compliance, and cure depth. The scope spans curable coatings, dental resins, photolithographic resists, and adhesive systems wherever a photoinitiator’s migration behaviour or spectral match is the claimed technical problem, not merely photopolymerization in general.
Filing activity peaked in 2018 and has since declined toward zero in the most recent complete years, a pattern consistent with a technology area where core chemistry has been claimed early and heavily by a small number of assignees. Publication lag of roughly 18 months means the tail end of the trend line will fill in further as more recent filings publish.
Filing trend and technology composition
Two views of the same 197 records: how filing volume moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend, 2017-2026
Filings rose to a peak of 36 in 2018, then fell steadily. The tracked 2021-to-2024 window shows a complete drop to zero filings, a -100% change; 2025 and 2026 remain partial due to publication lag and should not be read as confirming the trend either way yet.
IPC subclass composition
C08F (addition polymers) covers 64.5% of the 197 records and A61K (medicinal preparations) covers 58.4%, reflecting heavy dental- and coating-resin activity. G03F (photolithography) at 41.1% and C08G (condensation polymers) at 30.5% follow. Because records can carry multiple IPC classes, these shares sum to well over 100%.
Shares are the percentage of the 197 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Photoinitiator Systems and Migration with Eureka
This page is one run against one query. Ask Eureka your own question about photoinitiator systems and migration and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US20200010687A1 — UV-LED coating compositions
The present invention relates to UV-LED light curable coating compositions comprising a compound having at least one alpha, beta-ethylenically unsaturated polymerizable double bond, a type II photoinitiator system based on a thioxanthone and an amine, and a colorant. Optional inclusions are a type I photoinitiator and an optical brightener. The UV-LED curable composition provides good surface cure and low yellowing.Filed by Sun Chemical Corporation, published 2020-01-09.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5545676A | Ternary photoinitiator system for addition polymerization | 1,067 |
| 2 | JP1987018537A | Image forming material using photosensitive microcapsule containing third amine as coinitiator | 579 |
| 3 | US4735632A | Coated abrasive binder containing ternary photoinitiator system | 377 |
| 4 | US6025406A | Ternary photoinitiator system for curing of epoxy resins | 356 |
| 5 | US5998495A | Ternary photoinitiator system for curing of epoxy/polyol resin compositions | 273 |
| 6 | US6187833B1 | Ternary photoinitiator system for curing of epoxy/polyol resin composition | 248 |
| 7 | US6043295A | Ternary photoinitiator system for curing of epoxy resins | 161 |
| 8 | US6486226B2 | Phosphine oxide photoinitiator systems and curable compositions with low color | 139 |
| 9 | US5667541A | Coatable compositions, abrasive articles made therefrom, and methods of making and using same | 105 |
| 10 | US20050113477A1 | Photoinitiator systems with anthracene-based electron donors for curing cationically polymerizable resins | 86 |
Citation counts favour older records simply because they have had more time to accumulate citations; treat this as a signal of influence within the searched corpus, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three findings that shape where a new filing would actually have room to stand.
The core chemistry is already claimed by a few players
With 150 of 197 records concentrated among five assignees and the leader alone at 51, new entrants filing on core ternary or type II photoinitiator system chemistry are filing into dense prior art. The gap for new claims is more likely in application-specific formulation than in the base chemistry.
Filing activity has gone quiet at the leading assignees
Recent-year momentum shows zero filings in the latest tracked year across every one of the leading assignees, and the 2021-2024 window shows a full drop to zero. This does not necessarily mean the technology is exhausted — it may mean the leaders have shifted filing strategy or the area has matured into licensing and defence rather than new claims.
Dental and medical-device use cases are as prominent as coatings
A61K's near-parity with C08F suggests that a large share of photoinitiator migration concerns in this corpus originate from dental resin and biomedical curing applications, where extractables and food/tissue contact compliance are direct claim drivers, not incidental ones.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to photoinitiator systems and migration, with the prior art for and against each one.
Who holds the claim space
The ranked assignee list returns 43 companies total, counted in records — this is the complete ranking the data endpoint returns, not a top-50 or top-100 cut.
A single assignee holds more than a quarter of the field
The leading assignee's 51 records, against a field of 197, sets the density any new filer has to work around. Combined with strong co-assignee links to a university partner and a related corporate entity, this points to a long-running, well-defended research programme rather than opportunistic filing.
Beyond the top ten, filing is thin and scattered
Tenth place holds just 7 records, and the ranking runs to 43 assignees total. That drop-off from 76.1% at the top five to a long tail below tenth place suggests most organisations in this space filed a small handful of records rather than building a sustained portfolio.
Filing is clustered around one collaborative cluster
The strongest co-assignee pairs all link the same small group of related corporate and university entities, with the top pairing appearing 20 times. This concentration of co-filing suggests a single research partnership drives a meaningful share of the leading assignee's output.
| Assignee | Recent year | YoY |
|---|---|---|
| 3M Innovative Properties Co. | 0 | — |
| 3M Company | 0 | — |
| The Curators of the University of Missouri | 0 | — |
| Dentsply Detrey GmbH | 0 | — |
| S & C POLYMER SILICON UND COMPOSITE SPEZIALITAETEN GMBH | 0 | — |
| 3M Deutschland GmbH | 0 | — |
| Sun Chemical Corporation | 0 | — |
| Elkem Silicones France SAS | 0 | — |
Where to take this analysis
The dataset points to a mature, concentrated core with narrower application-specific openings still available.
Check freedom-to-operate against the leading cluster
Before filing on ternary or type II photoinitiator chemistry, screen against the leading assignee's portfolio and its closest co-filing partners, since together they account for the bulk of the top-five share.
Explore assignee portfolios in EurekaTest the under-claimed application branches
Food contact compliance, low-yellowing thin-film cure and dental-specific migration control show up in the corpus but at lower density than the core chemistry classes, and merit a closer novelty check.
Run a white space search in EurekaCommon questions on photoinitiator system patents
Highly concentrated. Five assignees hold 150 of the 197 records in scope, which is 76.1% of the field, and the single leading assignee accounts for 51 records on its own. The top ten assignees together reach 93.9% of all records, leaving a long tail of 43 ranked companies where most filed only a handful of records each. For a new entrant, this means the core ternary and type II photoinitiator chemistry is already densely claimed, and freedom-to-operate work should focus first on the leading cluster's portfolio.
Filing peaked in 2018 at 36 records and has fallen since, with the tracked 2021-to-2024 window showing a complete drop to zero filings, a -100% change. However, 2025 and 2026 figures are still incomplete because patent publication typically lags actual filing by around 18 months, so the most recent years understate true activity. The honest read is that activity has cooled from its 2018 peak, but it is too early to call the field dormant based on the last one or two years alone.
C08F (addition polymers) appears in 64.5% of the 197 records and A61K (medicinal preparations) in 58.4%, making these the two dominant classes. G03F (photolithography and photomechanics) follows at 41.1%, and C08G (condensation polymers) at 30.5%. Because a single patent record can carry multiple IPC classes, these percentages sum to more than 100%, and the overlap between A61K and C08F points to heavy activity in dental resin and biomedical curing applications specifically.
US20200010687A1, filed by Sun Chemical Corporation and published 2020-01-09, claims UV-LED light curable coating compositions built on a type II photoinitiator system pairing a thioxanthone with an amine, alongside a compound with an alpha, beta-ethylenically unsaturated double bond and a colorant. It optionally adds a type I photoinitiator and an optical brightener. Its stated advantage is good surface cure combined with low yellowing, which places it specifically in the UV-LED coatings sub-area rather than covering photoinitiator systems generally.
The corpus shows lower density in application-specific branches such as low-extractable type I systems aimed at food contact compliance, oxygen-inhibition mitigation for thin-film coatings, and migration-limited photoinitiators tuned for dental composites, compared to the heavily claimed core ternary photoinitiator chemistry. These branches appear in the dataset but without the concentration seen at the top of the assignee ranking. Any filing strategy here should still be checked against the leading assignees' broader portfolios, since their claims may extend into adjacent applications even if their record counts there are lower.
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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.