Blow Molding Patents: Who Leads, Where the Gaps Are 2026
- Filing has gone flat. the field peaked at 30 records in 2021 and 2022 held near that level at 28, with no renewed acceleration since.
- Concentration is moderate, not extreme. the leader alone accounts for 109 of 873 records, but the top 5 combined hold only 28.3% of all records — this is not a two-company field.
- Nearly all activity sits inside shaping claims. 95.9% of records carry a B29C shaping-of-plastics class, while layered-product claims under B32B reach only 8.0%.
What this landscape covers
This landscape covers 873 published records filed between 2015 and 2026 that combine blow molding process terms — extrusion blow molding and stretch blow molding among them — with specific technical claim language: parison programming, wall thickness distribution, preform design, top load strength and lightweighting. The scope is narrowed further by IPC classes covering plastics shaping (B29C49, B29C48) and container structure (B65D1), so the set is weighted toward process and container-geometry claims rather than raw material chemistry.
Because publication lags filing by roughly 18 months, the 2025 and 2026 figures in the trend chart understate real filing activity for those years; treat the drop-off at the right edge of the chart as an artefact of the data cut-off, not a genuine collapse in interest.
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Filing trends and technology composition
The two views below show how filing activity has moved year over year and how claims are distributed across IPC subclasses. Because a single record can carry several IPC classes, the composition shares add up to more than 100% of the 873 records in scope.
A flat trend after a 2021 peak
Filings rose from 9 records in 2017 to a peak of 30 in 2021, then held near that level at 28 in 2022 — evidence of a mature, steady-state field rather than one still accelerating. The most recent years are undercounted due to publication lag.
Shaping claims dominate; layered structures are a minor branch
B29C (shaping of plastics) covers 95.9% of records, confirming the corpus is centred on process claims. B65D (containers) at 27.1% and B29B (plastics preparation) at 18.1% are the next largest branches, while B32B (layered products) at 8.0% and C08L (polymer compositions) at 4.0% remain comparatively thin.
Shares are the percentage of the 873 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Blow Molding Technology with Eureka
This page is one run against one query. Ask Eureka your own question about blow molding technology and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
Method for injection stretch blow molding of polyethylene (US5620650A)
A method enabling stretch blow molding of polyethylene in a temperature range suited to both preform release and subsequent stretch blow molding, by disconnecting the core die and the preform in advance using gas pressure. The preform is injection molded, released from the cavity and core dies while the mouth portion is held by a lip die, then transferred into a blow die to stretch blow mold into a hollow thin-wall product.Filed by A.K. Technical Laboratory; granted 1997.
View full filing| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6391408B1 | Coated polyester preforms and method of making same | 186 |
| 2 | US6352426B1 | Mold for injection molding multilayer preforms | 159 |
| 3 | US6676883B2 | Methods for preparing coated polyester articles | 135 |
| 4 | US5921416A | Double-wall bottle and method and apparatus for molding the same | 123 |
| 5 | US5900293A | Collapsible, monolayer microwaveable container | 112 |
| 6 | US5989661A | Pressurized refill container resistant to sprue cracking | 108 |
| 7 | US4927679A | Preform for a monobase container | 76 |
| 8 | US6464106B1 | Stress crack resistant bottle | 74 |
| 9 | US4233262A | Method of forming blown polyethylene terephthalate containers | 74 |
| 10 | US6939591B2 | Polyester laminate materials | 73 |
Citation counts are drawn from the searched corpus and skew toward older filings; treat them as a signal of influence on later filers, not a measure of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for filing strategy
Three patterns stand out once the ranking, trend and IPC composition are read together: moderate concentration at the top, a plateaued filing rate, and heavy crowding in one claim branch alongside thin coverage in adjacent ones.
The top of the field is strong but not a monopoly
The leading assignee holds 109 records on its own, well ahead of the fifth-place holder at 21. Yet the top 5 combined take only 28.3% of all 873 records, and the top 10 still leave 60.5% of filings outside the leading group — this is a field with room for a well-differentiated new entrant, not one locked up by two or three players.
Filing has plateaued since 2021
The trend climbed from 9 records in 2017 to a peak of 30 in 2021, then essentially held flat at 28 in 2022. That pattern reads as a mature technology area where core process claims are largely staked out, rather than one still in a land-grab phase.
Shaping claims are the crowded ground
Almost every record in scope — 95.9% of 873 — carries a B29C shaping-of-plastics classification, making that branch the densest prior art to search before filing a new parison-control or wall-thickness claim. Container structure (B65D, 27.1%) and plastics preparation (B29B, 18.1%) are meaningfully less crowded.
Layered structures and polymer composition claims are thin
Layered-product claims under B32B reach only 8.0% of records, and polymer-composition claims under C08L reach just 4.0%. Given how dense the core shaping claims are, these adjacent branches are where new filings face the least prior art.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to blow molding technology, with the prior art for and against each one.
Who is filing, and where the next claim can still land
The assignee ranking spans 100 companies rather than a small clique, and recent-year momentum has cooled across the named leaders — none of the six most-tracked assignees added a record in the latest year. That combination points to a field where incumbents hold ground built years ago but are not visibly expanding it right now.
One clear leader, no runaway gap to second
The top-ranked assignee holds 109 records against 21 at fifth place — a real lead, but the drop to the rest of the top 10 (19 at tenth place) is gradual rather than a cliff, meaning the leader's position rests on volume built over years rather than a single blocking family.
Most of the field sits outside the top 10
With the top 10 combined at 39.5% of all 873 records, well over half of filing activity comes from assignees outside that leading group — evidence of a fragmented base of process specialists, container makers and equipment builders rather than a field owned by a handful of firms.
Recent-year filing has gone quiet among named leaders
Every one of the six most closely tracked assignees in this dataset shows zero filings in the latest year. Read alongside the flat 2021-2022 trend, this suggests incumbents are maintaining existing portfolios rather than actively extending them right now — an opening for a challenger filing in the same period.
| Assignee | Recent year | YoY |
|---|---|---|
| Nissei ASB Machine Co., Ltd. | 0 | — |
| Aoki Katashi Laboratory Co., Ltd. | 0 | — |
| Procter & Gamble Co. | 0 | — |
| Yoshino Kogyosho Co., Ltd. | 0 | — |
| Milacron LLC | 0 | — |
| Avient Colorants Italy S.r.l. | 0 | — |
| Fina Technology, Inc. | 0 | — |
| Advanced Plastics Technologies Luxembourg S.A. | 0 | — |
Where to take this from here
The dataset points to two practical next steps: check freedom-to-operate against the densest shaping claims before filing, and look closely at the thinner adjacent branches for open claim space.
Search the B29C core before drafting new claims
With 95.9% of records carrying a B29C classification, any new parison-programming or wall-thickness claim is likely to sit close to existing art. Run a focused prior-art search against this branch specifically, not the field as a whole.
Explore B29C prior art in Eureka →Test the white space in layered and composition claims
B32B layered-product claims (8.0%) and C08L polymer-composition claims (4.0%) are comparatively open relative to the shaping core. A first claim drafted specifically against these branches faces less crowding.
Map white space in Eureka →Watch for renewed filing after the lag window closes
The apparent drop-off in 2025-2026 reflects publication lag, not necessarily reduced R&D activity. Re-check the trend in 12-18 months before concluding the field has genuinely gone quiet.
Track filing trends in Eureka →Common questions about blow molding patents
The leading assignee in this dataset holds 109 of the 873 records in scope, a clear lead over the rest of the field. However, the top 5 assignees combined account for only 28.3% of all records, and the top 10 combined reach 39.5% — so no single company or small group controls the majority of filings. Anyone assessing freedom to operate should look at the ranked leaders as a group rather than assuming one company blocks the field.
No, filing activity has plateaued rather than continuing to grow. It rose from 9 records in 2017 to a peak of 30 in 2021, then held essentially flat at 28 in 2022. The apparent decline in 2025-2026 is partly an artefact of publication lag, which typically runs about 18 months, so the true picture for the most recent years will only become clear once those filings publish.
Shaping-of-plastics claims under IPC class B29C dominate, appearing in 95.9% of the 873 records in scope. Container and packaging claims under B65D follow at 27.1%, and plastics-preparation claims under B29B sit at 18.1%. Because a single patent can carry multiple IPC classes, these shares add up to more than 100% of the record total, which is expected.
The thinnest coverage relative to the shaping core sits in layered-product claims under B32B, at 8.0% of records, and polymer-composition claims under C08L, at just 4.0%. These branches sit adjacent to the dense parison and wall-thickness claim space but carry far fewer filings, making them worth a targeted prior-art check before assuming they are occupied. A first claim there would need to tie a specific layered-structure or composition detail to a stated blow molding process step to stand apart from the shaping-claims corpus.
US5620650A, filed by A.K. Technical Laboratory, claims a method for injection stretch blow molding of polyethylene that uses gas pressure to disconnect the core die from the preform ahead of the blow step, enabling release and subsequent stretching in a temperature range suited to polyethylene specifically. It sits among the most-cited records in this corpus, which signals it has been a reference point for later filers working on preform release and stretch-blow sequencing. Citation counts in a searched corpus skew toward older filings, though, so its high citation count reflects historical influence rather than current commercial dominance.
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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.