Resin Transfer Molding Patents: Top Companies & Trends 2026
- 38.4% of all filings sit with five assignees. the top five combined hold 103 of the 268 records in scope, with a long tail of single- and low-count filers behind them.
- Filing has not grown since the peak. activity topped out at 9 records in 2020 and sat at 6 by the 2022 midpoint, pointing to a mature, not expanding, filing base.
- The field is claimed almost entirely under one IPC subclass. B29C accounts for 90.3% of the 268 records, while adjacent classes like B29D and C08G sit under 7%.
What this landscape covers
This dataset tracks patent activity in resin transfer molding (RTM) and vacuum infusion, focused on core process controls: preform permeability, flow front behaviour, dry spot formation, injection pressure and cure cycle management. The scope is defined by a search across titles and abstracts combined with IPC classes B29C70, B29C39 and C08J5, and covers 268 published records from 2015 through the 2026-07-31 cut-off.
Because publication typically lags filing by around 18 months, the counts for the most recent year understate real filing activity and should be read as a floor, not a ceiling.
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Filing trend and technology composition
Two views of the same 268 records: how filing activity has moved year over year, and how those records distribute across IPC subclasses.
Filing trend, 2017–2026
Filings rose from 2 records in 2017 to a peak of 9 in 2020, then eased back toward the 2022 midpoint of 6 — a flat-to-declining pattern rather than sustained growth. The 2026 figure is partial because of publication lag and should not be read as a drop-off.
IPC subclass composition
B29C (shaping of plastics) covers 90.3% of the 268 records, confirming this is fundamentally a shaping-process field. B29K, C08J and B29L each sit near 12-15%, and B32B, C08L, C08G and B29D trail further behind — these narrower slices are where composition, laminate and specific-article claims concentrate. Because records can carry multiple IPC classes, these shares add up to more than 100% of the 268-record total.
Shares are the percentage of the 268 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Resin Transfer Molding and Infusion with Eureka
This page is one run against one query. Ask Eureka your own question about resin transfer molding and infusion and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this field
System for performing an RTM process with multiple injection technology and resin transfer molding process
The filing describes a molding tool with upper and lower mold halves forming a cavity for a preform, controlled by a main control unit coordinating multiple injection units and injection points feeding resin into the cavity — an approach aimed at managing flow front and fill behaviour across large or complex preforms via distributed injection rather than a single feed point.Filed by 1C Composites Engineering GmbH, published 2026-04-30 — one of the most recent records in the dataset.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4992228A | Method for preparing preforms for molding processes | 215 |
| 2 | US20020022422A1 | Double bag vacuum infusion process and system for low cost, advanced composite fabrication | 199 |
| 3 | US5152949A | Tooling method for resin transfer molding | 176 |
| 4 | US6537470B1 | Rapid densification of porous bodies (preforms) with high viscosity resins or pitches using a resin transfer … | 109 |
| 5 | US5518385A | Apparatus for resin transfer molding | 107 |
| 6 | US6048488A | One-step resin transfer molding of multifunctional composites consisting of multiple resins | 106 |
| 7 | US7413694B2 | Double bag vacuum infusion process | 105 |
| 8 | US5204042A | Method of making composite laminate parts combining resin transfer molding and a trapped expansion member | 96 |
| 9 | US5686038A | Resin transfer molding of composite materials that emit volatiles during processing | 93 |
| 10 | US5851336A | Resin transfer molding in combination with honeycomb core | 89 |
Citation counts favour older records simply because they have had more time to accumulate citations inside a searched corpus — treat this as a measure of influence on subsequent filings, 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 stand out once the filings are ranked, dated and classified.
Filings concentrate early, then thin out fast
The leading assignee alone holds 37 records, and the top five combined hold 103 of the 268 records in scope. By the tenth-ranked assignee, the count has dropped to 5 — a steep drop from leader to mid-field that signals most of the durable claim space near the core process was staked out early.
Growth peaked years ago and has not returned
Filing activity climbed from 2 records in 2017 to a peak of 9 in 2020, then eased to 6 by 2022. None of the assignees with the largest historical portfolios show filings in the most recent year, consistent with a field where the core process is settled rather than actively being re-claimed.
Almost everything sits under one shaping-process class
B29C covers 90.3% of the 268 records, dwarfing every other class. The narrower slices — B32B laminates, C08L compositions, C08G condensation polymers, B29D specific articles — each sit under 11% and mark where more specific, less crowded claim territory exists.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to resin transfer molding and infusion, with the prior art for and against each one.
Who is filing, and who has gone quiet
The ranking covers 100 companies counted by record share; it is the full ranking the dataset returns, not a curated top list.
One assignee well ahead of the field
The leading assignee holds 37 records against a fifth-place count of 11 and a tenth-place count of 5 — a steep gradient that puts real distance between the leader and everyone else, rather than a tight cluster at the top.
Half the field sits with ten organisations
The top 10 combined account for 134 of the 268 records, exactly half the dataset. The remaining half is spread across the other 90 ranked assignees, many with only a handful of filings each.
The biggest historical filers are not filing now
Several of the largest assignees by cumulative count show zero filings in the most recent year. That does not necessarily mean they have exited the space — recent filings may simply not have published yet — but it does mean current activity cannot be read off historical leaderboard position alone.
| Assignee | Recent year | YoY |
|---|---|---|
| The Boeing Company | 0 | — |
| LM Glasfiber | 0 | — |
| United Technologies Corporation | 0 | — |
| Honeywell International Inc. | 0 | — |
| Cytec Technology Corp. | 0 | — |
| Toho Tenax Co., Ltd. | 0 | — |
| HURDLE ERIC | 0 | — |
| Lonza Group AG | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, portfolio strategy or technology scouting.
Check freedom-to-operate against the most-cited records
The five most-cited patents in this dataset, several dating to the 1990s and early 2000s on core tooling and vacuum infusion apparatus, still shape how later filings are drafted. Any new filing near preform tooling or double-bag infusion should be checked against these first.
Run a freedom-to-operate checkTrack the assignees that have gone quiet
Several of the largest historical filers show no filings in the most recent year. Watching whether that is a real pullback or a publication-lag artefact matters for anyone assessing competitive pressure in this space.
Set up assignee monitoringExplore the narrower IPC branches
Classes like B29D, C08G and C08L each cover well under a fifth of the 268 records. These narrower slices around specific articles and resin chemistries carry lighter claim density than the dominant B29C shaping class.
Explore white space with EurekaCommon questions about this landscape
In this dataset of 268 records, one assignee leads with 37 records, well ahead of the fifth-ranked assignee at 11. The top five assignees combined hold 103 records, or 38.4% of all records in scope, so leadership is concentrated but not exclusive. Beyond the top ten, which together hold 50.0% of the dataset, filings spread thinly across a long tail of organisations with only a handful of records each.
The trend is flat to declining rather than growing. Filings rose from 2 records in 2017 to a peak of 9 in 2020, then eased to 6 by the 2022 midpoint. The most recent years show lower counts, but because publication typically lags filing by about 18 months, the last one or two years understate real activity and should not be read as a hard drop-off.
The overwhelming majority of records, 90.3% of the 268 in scope, are classified under B29C, the IPC subclass covering shaping of plastics — confirming this is primarily a process-engineering field rather than a materials-chemistry one. Smaller shares fall under B29K, C08J and B29L, each around 12-15%, with narrower slices in B32B laminates, C08L compositions, C08G condensation polymers and B29D specific articles. Because a single record can carry multiple IPC classes, these percentages add up to more than 100% of the record total.
The most-cited record in this dataset is a method for preparing preforms for molding processes, cited 215 times, followed closely by a double-bag vacuum infusion process cited 199 times and a resin transfer molding tooling method cited 176 times. High citation counts in a searched corpus tend to favour older patents simply because they have had more time to accumulate citations, so these figures signal historical influence on how later patents were drafted rather than current commercial dominance.
The narrower IPC classes in this dataset carry noticeably lower filing density than the dominant B29C shaping class. C08G condensation polymer chemistries sit at 6.0% of the 268 records and B29D specific plastic articles at 4.9%, both well below the 90.3% concentration in core shaping claims. Sub-areas around multi-point injection control, cure cycle sensing and laminate-specific dry spot detection show comparatively light claim coverage and are worth checking closely before drafting new claims there.
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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.