Gas-Assisted & Foam Injection Molding Patents: Leaders & Trends 2026
- Concentrated at the top. The top 5 assignees hold 59.7% of all 62 records in scope, and the top 10 hold 80.6% — this is a field with a small set of entrenched positions, not a fragmented one.
- Filing has flattened, not grown. Activity peaked at 8 records in 2020; the 2022 midpoint shows no filings, and the trend into 2026 is flat to declining rather than expanding.
- Claim space sits overwhelmingly in one subclass. 83.9% of records carry a B29C shaping classification, while adjacent areas like implant-grade parts (A61F, 11.3%) and additive formulations (C08K, 9.7%) are comparatively thin.
What this landscape covers
This review covers 62 published records at the intersection of gas-assisted, foam and microcellular injection molding, filtered to documents that specifically address hollow sections, sink-mark elimination, cell structure, weight reduction or surface quality — the practical problems that separate a molding patent from a materials patent. The search spans B29C45 and B29C44 (injection and foam moulding apparatus) together with C08J9 (cellular polymer products), so it captures both the process-control claims and the resulting foamed-part chemistry.
Coverage runs from 2015 through the data cut-off of 2026-07-31. Publication typically lags filing by around 18 months, so the most recent one to two years in any trend line will understate actual filing activity rather than reflect a real slowdown.
Filing trend and technology composition
Two views of the same 62-record dataset: how filing activity has moved year over year, and how those records distribute across IPC subclasses.
Filing trend, 2017-2026
Filings rose to a peak of 8 records in 2020, then fell away; the 2022 midpoint recorded zero filings and the line into 2026 (partial year) stays flat to declining rather than recovering.
IPC subclass distribution
B29C (shaping of plastics) covers 83.9% of the 62 records, far ahead of C08J (37.1%) and C08L (22.6%). Because a record can carry multiple classes, these shares sum past 100% and should be read against the 62-record total, not against each other.
Shares are the percentage of the 62 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Gas-Assisted and Foam Injection Molding with Eureka
This page is one run against one query. Ask Eureka your own question about gas-assisted and foam injection molding and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this dataset
US8696957B2 — Methods for microcellular injection molding
In a method of microcellular injection molding, a polymer and a supercritical fluid are processed. A condition of processing the polymer and/or the supercritical fluid is adjusted to control a weight of a plastic part and/or a surface characteristic of a plastic part produced. In another method, a polymer is heated and melted and a supercritical fluid is added, forming a single-phase polymer-gas solution. The polymer and/or supercritical fluid conditions are adjusted to control part weight and/or surface characteristic.Filed by Wisconsin Alumni Research Foundation; published 2014-04-15.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20100198133A1 | Microcellular injection molding processes for personal and consumer care products and packaging | 59 |
| 2 | US6019918A | Gas assisted injection molding with controlled internal melt pressure | 56 |
| 3 | US6939504B2 | Plastic injection molding with moveable insert members | 46 |
| 4 | US6645587B1 | Gas assisted injection molding with controlled internal melt pressure | 31 |
| 5 | US8696957B2 | Methods for microcellular injection molding | 18 |
| 6 | US6896844B2 | Process for gas assisted and water assisted injection molding | 16 |
| 7 | US6730262B1 | Plastic injection molding with rotating insert members | 15 |
| 8 | US6821476B2 | Gas assisted injection moulding | 15 |
| 9 | WO2017102762A1 | Process for producing foam molded parts with aesthetic surfaces by foam injection molding | 10 |
| 10 | JP2008093860A | System, program, and method for forecasting quality of foamed injection-molded article | 9 |
Citation counts reward older, earlier-filed records within this searched corpus — treat them as a signal of influence on the field's vocabulary, not as a ranking of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three findings that shape how a competitive or freedom-to-operate review of this space should be scoped.
A small group holds most of the filed positions
The top 5 assignees account for 59.7% of all 62 records in scope, and the top 10 account for 80.6%. That leaves a long tail of single- or low-filing entrants competing for the remaining share — a structure where a new entrant is more likely to be designing around an incumbent than filing into open ground.
Activity has plateaued since its 2020 peak
Filings rose through the late 2010s to a peak of 8 records in 2020, then the 2022 midpoint shows zero recorded filings. Combined with the usual 18-month publication lag, the picture into 2026 is one of a mature, flat-to-declining filing rate rather than an expanding one.
Claim activity is heavily process-side, not formulation-side
B29C (shaping of plastics) touches 83.9% of records, while additive- and composition-heavy classes such as C08K (9.7%) and B29L (8.1%) are comparatively thin. That imbalance suggests the process-control claims — melt pressure, gas/supercritical-fluid dosing, mould-cavity control — are the dense ground, while formulation-side claims see less filing pressure.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to gas-assisted and foam injection molding, with the prior art for and against each one.
Who holds the ground, and where the field is still open
The ranked leaders sit on the dense process-control claims; the gaps are in adjacent formulation and application areas that see far fewer filings.
One filer sets the pace at the top of the ranking
The leading assignee holds 10 of the 62 records in scope, roughly double the fifth-place count of 4. That gap between first and fifth place indicates a genuine leader rather than a cluster of near-equal competitors at the top.
The middle of the ranking narrows quickly
Filing counts drop from 4 records at fifth place to 2 at tenth place, meaning the top-10 cohort itself is uneven — a handful of firms with multiple filings, then several with only two or three.
Co-filing is limited and concentrated around one pairing
Only 10 co-assignee pairs appear across the dataset, and the strongest pairing (5 shared records) links a consumer-products filer with a university research foundation — suggesting most other filers in this space are prosecuting alone rather than through joint development filings.
| Assignee | Recent year | YoY |
|---|---|---|
| Lear Corporation | 0 | — |
| Playtex Products, Inc. | 0 | — |
| INEOS Styrolution Group GmbH | 0 | — |
| Wisconsin Alumni Research Foundation | 0 | — |
| UBE Machinery Corporation, Ltd. | 0 | — |
| Polyplastics Co., Ltd. | 0 | — |
| Kraton Polymers Research B.V. | 0 | — |
| SHPP Global Technologies B.V. | 0 | — |
Where to take this analysis
This landscape frames the concentration and the gaps; turning that into a filing or freedom-to-operate decision needs a closer read of the specific claims involved.
Check freedom-to-operate against the leading claims
The top-cited records, including US8696957B2 and the earlier US6019918A family, define the internal melt-pressure and supercritical-fluid control methods that much of the field cites. Any new process-control filing should be checked against these first.
Explore in EurekaProbe the under-claimed branches before committing claim language
The A61F, C08K and B29L overlaps carry noticeably fewer records than the core B29C shaping class. A first claim aimed at implant-grade or additive-modified cellular structures has more room to define its own boundaries.
Explore in EurekaCommon questions about this landscape
The dataset ranks 37 companies by patent family count, with the leading assignee holding 10 of the 62 records in scope and the top 5 combined holding 59.7% of all records. That concentration means a small number of firms — spanning automotive components, consumer products, and specialty polymer chemistry — hold most of the filed process-control positions, while a long tail of single-filing entrants holds the rest. Anyone assessing this space should treat the top 10, which together hold 80.6% of records, as the primary group to check for overlapping claims.
Filing activity peaked at 8 records in 2020 and has not returned to that level since; the 2022 midpoint recorded zero filings, and the trend into 2026 reads flat to declining. Because publication typically lags filing by around 18 months, the most recent one to two years will understate true activity, but even accounting for that lag the multi-year pattern is one of plateau rather than growth. This suggests the core process-control claim space is largely settled rather than still being actively contested.
US8696957B2, assigned to Wisconsin Alumni Research Foundation, claims methods of microcellular injection molding where a polymer and a supercritical fluid are combined into a single-phase polymer-gas solution, with processing conditions adjusted to control part weight and surface characteristics. It is one of the most-cited records in this dataset, alongside earlier gas-assisted melt-pressure control patents, indicating it has shaped how later filings describe supercritical-fluid dosing and part-weight control. A new filing working with supercritical-fluid microcellular processes should review its specific claim language on solution-phase formation and condition adjustment before committing to similar process steps.
The IPC composition shows heavy concentration in B29C (shaping of plastics, 83.9% of records) with comparatively light coverage in A61F (implants and prostheses, 11.3%), C08K (additives, 9.7%) and B29L (indexed plastic products, 8.1%). That gap suggests formulation-side and application-specific claims — such as additive-modified cellular structures or implant-grade microcellular parts — see far less filing pressure than the core melt-pressure and mould-cavity process claims. These branches are worth a closer freedom-to-operate check precisely because they are less crowded, not because they are commercially untested.
Among the receiving offices in this dataset, the United States leads with 24 records, followed by the European Patent Office with 8, and Canada and Japan each with 6. The WIPO PCT route accounts for 5 records and South Korea 4, indicating that while most applicants pursue direct national filing in the US, a meaningful share also seek broader international coverage through PCT before narrowing to specific jurisdictions.
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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.