Epoxy Resin Molding Process Patents: Leaders & Filing Trends 2026
- Filings peaked in 2017 at 81 and have declined since, with 2022's midpoint of 27 confirming a flat-to-declining trend rather than a temporary dip.
- None of the leading assignees show any filings in the latest year, a pattern consistent across Toray Industries, Inc., Mitsubishi Rayon Co., Ltd., Dow Global Technologies LLC and others — a sign the field has gone quiet at the top even before accounting for publication lag.
- B29C dominates at 1,284 of 1,297 records, but C08J, C08G and C08L each carry over a quarter of the corpus, showing the real contest is over resin chemistry claimed alongside the molding step, not the molding step alone.
Filing growth compares 2021 (52 records) with 2024 (38) — 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 1,297 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape tracks patent families at the intersection of epoxy resin formulation and molding process claims — resin transfer molding, compression molding, resin infusion and related molding-process language — filed or published between 2015 and mid-2026. The corpus is built from title/abstract language plus IPC classification codes B29C70, B29C39 and B29C43, which target shaping-of-plastics claims rather than resin chemistry alone.
1,297 families sit in this set. Filing activity is concentrated in the United States, Japan, Europe and China as receiving offices, with the WIPO/PCT and Canadian filings a smaller supplementary channel. Because publication typically lags filing by around 18 months, the last one to two years in any trend chart will understate true filing activity — read the tail of the curve as a floor, not a ceiling.
Filing trend and technology composition
Two views of the same 1,297 families: how filing volume has moved year over year, and which IPC subclasses the claims actually sit in.
A peak in 2017, then a long decline
2017's 81 filings is the high point of the window. By the midpoint year of 2022, filings had fallen to 27, and the count continues down toward the partial 2026 figure of 6. This is not a data artefact of the current year being incomplete — the decline is visible well before the most recent, still-filling years.
B29C dominates, but the supporting chemistry classes are substantial
B29C (shaping of plastics) appears in nearly every record, as expected given the search construction. The more informative signal is underneath: C08J (polymer processing), C08G (condensation polymers) and C08L (polymer compositions) each cover roughly a quarter to a third of the corpus, and B32B (laminates) and C08K (additives) are close behind. Claims in this space are rarely about the mold alone — they pair a molding step with a specific resin, additive or laminate architecture.
Shares are the percentage of the 1,297 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Epoxy Resin Molding Process with Eureka
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Try EurekaThe most-cited prior art in this corpus
Process for Preparing Composites Using Epoxy Resin Formulations
The invention is a process for making reinforced composites using an epoxy resin composition. The epoxy resin compositions are hardened using a gem-di(cyclohexylamine)-substituted alkane as a hardener and a tertiary amine compound, a heat-activated catalyst, or a mixture thereof as an accelerator. This epoxy resin composition has a long open time, and then cures rapidly in a mold in the presence of a reinforcement. These cure characteristics make the composition well suited for use in manufacturing processes such as resin transfer molding (RTM), vacuum-assisted resin transfer molding (VARTM), Seeman Composites Resin Infusion Molding Process (SCRIMP) and reaction injection molding (RIM).Filed by DOW GLOBAL TECHNOLOGIES LLC, published 2008-12-18 — predates this landscape's filing window but remains a foundational reference for open-time/cure-rate claims in RTM and infusion processes.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20110189440A1 | Systems, Devices, and/or Methods for Manufacturing Castings | 289 |
| 2 | US9315663B2 | Systems, devices, and/or methods for manufacturing castings | 201 |
| 3 | US5449480A | Method of producing boards for printed wiring | 189 |
| 4 | US4681718A | Method of fabricating composite or encapsulated articles | 165 |
| 5 | US4648921A | Method of making fiber reinforced articles | 141 |
| 6 | WO1993021010A1 | Lenses with high impact resistance and high scratch resistance | 105 |
| 7 | US5333527A | Compression molded composite guitar soundboard | 98 |
| 8 | US3873654A | Process of forming a rigid foam airfoil section | 94 |
| 9 | US6221297B1 | Method of manufacturing a transformer coil with a disposable wrap and band mold and integrated winding mandrel | 91 |
| 10 | US5698318A | Process for resin transfer molding and formulations useful to practice it | 72 |
Citation counts inside a searched corpus favor older filings — treat this as a map of influential prior art, not a ranking of current relevance.
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Browse MCP servers →What the numbers say about the state of the field
Three patterns stand out once filing volume, IPC composition and citation data are read together.
A field past its filing peak
2017's peak of 81 filings has not been approached since; the midpoint year of 2022 sat at 27. Even allowing for publication lag depressing the last one to two years, the decline predates the most recent filings and looks structural rather than a reporting gap.
Leaders have gone quiet simultaneously
Toray Industries, Inc., Mitsubishi Rayon Co., Ltd., Mitsubishi Chemical Corporation, Cytec Industries Inc., Dow Global Technologies LLC and Resonac Corporation (formerly Showa Denko) all show zero filings in the latest year. That is a synchronized pause across the field's most active filers, not one company retreating while others advance.
Molding claims almost never stand alone
Because C08J, C08G, C08L, B32B and C08K each appear in roughly a quarter to a third of records, most claims pair a shaping/molding step with specific resin chemistry, additive packages or laminate architecture. A molding-process claim filed without chemistry specificity is filing into the most crowded, least differentiated part of the space.
Co-filing is rare and thin
Only ten co-assignee pairs appear across the corpus, and the strongest ties are single-instance pairings involving Toray Industries, Inc. and named inventors. This is a field of solo assignees more than joint ventures or cross-licensed development programs.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to epoxy resin molding process, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Toray Industries, Inc. | YOSHIOKA KENICHI | 1 |
| Toray Industries, Inc. | MIYOSHI MASAYUKI | 1 |
| Toray Industries, Inc. | KOCHI SHINJI | 1 |
| Toray Industries, Inc. | KAMAE TOSHIYA | 1 |
| Dow Global Technologies LLC | VERGHESE NIKHIL K E | 1 |
| Dow Global Technologies LLC | TURAKHIA RAJESH H | 1 |
| Dow Global Technologies LLC | SHIELDS NIGEL | 1 |
| Dow Global Technologies LLC | REIMERS MARTIN | 1 |
With only 10 co-assignee pairs across 1,297 families, most filings originate from a single assignee working independently.
Who holds the claim space
Filing counts point to a small group of materials and composites companies with sustained historical activity, though none show recent-year filings in this dataset.
Toray's historical lead
Toray Industries, Inc. (Toray Industries) anchors the top of the ranking and is the only assignee appearing in multiple co-assignee pairs, suggesting internal inventor teams filing jointly rather than external collaboration.
Two Mitsubishi entities, same claim territory
Mitsubishi Rayon Co., Ltd. and Mitsubishi Chemical Corporation both sit among the leading assignees, reflecting overlapping materials-science filing across related Mitsubishi group entities rather than a single consolidated filer.
Cytec's aerospace-composite angle
Cytec Industries Inc. (Cytec Industries) brings an aerospace-composite filing history to this space, distinct from the commodity-resin filers, and its presence among leaders signals the field spans both industrial and aerospace-grade applications.
| Assignee | Recent year | YoY |
|---|---|---|
| Toray Industries, Inc. | 0 | — |
| Mitsubishi Rayon Co., Ltd. | 0 | — |
| Mitsubishi Chemical Corporation | 0 | — |
| Cytec Industries Inc. | 0 | — |
| Dow Global Technologies LLC | 0 | — |
| Resonac Corporation (formerly Showa Denko) | 0 | — |
| Nippon Steel & Sumikin Micro Metal Corporation | 0 | — |
| B.F. Goodrich Company (USA) | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether you're clearing a filing or scoping a design-around.
Run a freedom-to-operate check on chemistry-specific claims
Since most claims pair a molding step with resin chemistry, additive package or laminate structure, a clearance search needs to cover C08J/C08G/C08L/C08K alongside B29C — not the molding IPCs alone.
Explore in Patsnap Eureka →Watch for renewed filing after the lag window clears
With the leading assignees showing zero filings in the latest year and publication lagging filing by about 18 months, it's too early to call this field dormant — re-check the trend once 2025–2026 filings finish publishing.
Track filing activity in Patsnap Eureka →Scope a design-around for foundational cure-chemistry claims
US20080308972A1's hardener/accelerator combination is a common reference point for RTM and infusion cure-rate claims; mapping its claim boundaries against newer chemistry is a reasonable next step before filing in that space.
Analyze this patent in Patsnap Eureka →Common questions about epoxy resin molding process patents
The leading assignees in this dataset are Toray Industries, Inc. (Toray Industries), Mitsubishi Rayon Co., Ltd. and Mitsubishi Chemical Corporation (Mitsubishi Rayon and Mitsubishi Chemical), Cytec Industries Inc. (Cytec Industries), Dow Global Technologies LLC (Dow Global Technologies) and Resonac Corporation (formerly Showa Denko) (Resonac). These are historical leaders by cumulative filing count across 2015–2026, not necessarily current filers — none of them show filings in the latest year of this dataset. Toray stands out further by appearing in multiple co-assignee pairings, suggesting a pattern of joint internal filing among its inventor teams.
Filing activity peaked in 2017 at 81 families and has declined since, with the midpoint year 2022 down to 27 and the partial latest year at just 6. This is a flat-to-declining trend, not a temporary dip caused by incomplete recent data — the decline is visible well before the years most affected by publication lag. Readers should treat the last one to two years of any chart as understated due to the roughly 18-month gap between filing and publication, but that alone doesn't explain a multi-year decline that started years earlier.
Beyond the core B29C shaping-of-plastics classification, which appears in nearly all 1,297 records, the next-largest IPC groups are C08J (polymer processing and solutions), C08G (condensation polymers) and C08L (polymer compositions), each covering roughly a quarter to a third of the corpus. B32B (laminates) and C08K (polymer additives) follow closely behind. In practice, this means most claims combine a molding or shaping step with specific resin chemistry, additive formulation or laminate structure — a standalone molding-process claim without chemistry specificity is filing into the most contested part of the space.
US20080308972A1, assigned to DOW GLOBAL TECHNOLOGIES LLC and published 2008-12-18, claims an epoxy resin composition hardened with a gem-di(cyclohexylamine)-substituted alkane hardener plus a tertiary amine or heat-activated catalyst accelerator, tuned for long open time followed by rapid in-mold cure. It explicitly names RTM, VARTM, SCRIMP and RIM as its target processes, making it a foundational reference for cure-rate claims in resin transfer and infusion molding. Whether it blocks a new filing depends on whether the new hardener/accelerator chemistry falls within its specific compound class — a claim built on a different hardener chemistry with similar open-time/cure-rate behaviour would need its own freedom-to-operate check rather than assuming automatic conflict.
The technology composition data suggests thinner claim density in areas like low-viscosity infusion resin systems, additive-modified compression molding cycles, laminate-integrated cure-monitoring, and recycled-fiber reinforcement within RTM processes — these sit at the intersection of well-covered classes (B29C, C08J, B32B) but combine them in ways less densely claimed than core resin-transfer chemistry. The overall decline in filing since 2017, combined with zero latest-year filings among historical leaders, also suggests the field may be underexplored relative to its earlier activity, though a design team should confirm this with a targeted clearance search rather than relying on filing counts alone.
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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.