Polystyrene Films and Microspheres Patents: Leaders & White Space 2026
- Filing has cooled since 2018. The peak year was 2018 at 41 filings; by the 2022 midpoint output had dropped to 22, and the trend has stayed flat or declined since.
- Claim density sits in composition, not shaping. C08L (polymer compositions) and C08J (processing) dominate the IPC mix at 1,450 and 866 records, while B29C (plastics shaping) trails at just 116.
- Recent-year momentum has stalled across the biggest names. Several of the most active historical filers, including BASF, Dow, and Asahi Kasei, show zero new filings in the latest tracked year.
Filing growth compares 2021 (25 records) with 2024 (16) — 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 1,837 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape tracks 1,837 patent families filed against suspension polymerization, particle size distribution, film extrusion, monodisperse particle control, and surface modification in polystyrene systems, spanning publications from 2015 through mid-2026. The search combines classic expanded polystyrene process claims with the newer microsphere and surface-modified particle work that has migrated into adjacent IPC classes over the same period.
Coverage runs across six major receiving offices, with the United States, Europe, and Japan carrying the largest share of filings and China and the WIPO PCT route forming a smaller but active secondary tier. Because publication typically lags filing by around eighteen months, the most recent year in any trend line understates true filing activity and should be read as a floor, not a ceiling.
Filing trends and technology composition
The filing curve and the IPC mix together explain where claim pressure has actually built up in polystyrene film and microsphere work, and where it has not.
A decade of flattening output
Filings ran from 29 in 2017 up to a peak of 41 in 2018, back down to 22 at the 2022 midpoint, and down to 7 in the most recent (partial) year. That shape reads as a technology that had its filing surge, plateaued, and has been contracting rather than expanding for several years running.
Composition claims dominate the classification mix
C08L (polymer compositions) leads at 1,450 records, ahead of C08J (polymer processing) at 866 and C08F (addition polymers) at 767. Shaping-focused B29C sits far behind at 116, and condensation-polymer and catalysis-adjacent classes (C08G, B01J) are smaller still — a strong signal that most of the claim activity in this space is about what the polymer is made of and how it is processed, not how it is physically formed into parts.
Shares are the percentage of the 1,837 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Polystyrene Films and Microspheres with Eureka
This page is one run against one query. Ask Eureka your own question about polystyrene films and microspheres and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
Process for making gray expanded polystyrene
Gray expanded polystyrene achieving target molecular weight, bead size, bead distribution, and cell structure may be reproducibly prepared by suspension polymerization by introducing to the suspension polymerization an additive that is carbon black and/or graphite only after approximately 20 to 60 wt% of the styrene monomer has been converted to polystyrene. Introducing the additive at this point slows the polymerization rate, allowing droplet size to equilibrate to the desired target range.Filed by Nucera Solutions LLC, published 2019-04-18 as US20190112447A1.
View full filing| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6444343B1 | Polymer electrolyte membranes for use in fuel cells | 154 |
| 2 | US6521712B1 | Glass-clear impact-modified polystyrene based on styrene-butadiene block copolymers | 136 |
| 3 | EP0786480A1 | Polymer polyol and process for the preparation of polymer polyols | 135 |
| 4 | US6160027A | Process for the preparation of polymer particles | 115 |
| 5 | US6593430B1 | Transparent, impact-resistant polystyrene on a styrene-butadiene block copolymer basis | 114 |
| 6 | WO1998022989A1 | Novel polymer electrolyte membranes for use in fuel cells | 105 |
| 7 | JP1985238345A | Resin composition | 104 |
| 8 | US5424346A | Biodegradable replacement of crystal polystyrene | 89 |
| 9 | US20040152795A1 | Foamable interpolymer resin particles containing limonene as a blowing aid | 87 |
| 10 | WO2006061571A1 | Expandable polystyrene composition | 71 |
Citation counts inside a searched corpus favour older filings; treat this table as a map of influence on later filings, not a ranking of current commercial importance.
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Three patterns stand out once the filing trend and citation graph are read together.
The surge is over, not starting
Output peaked in 2018 and has fallen in nearly every interval since, including a drop to 22 at the 2022 midpoint and 7 in the latest partial year. New entrants filing broad composition claims now are filing into a space that has already been substantially mapped, not an emerging one.
Composition claims crowd the field; shaping claims do not
Nearly eight times as many records sit in polymer-composition classification (C08L) as in plastics-shaping (B29C). That imbalance suggests process and formulation variants around bead composition, additives, and particle structure are heavily claimed, while equipment- and shaping-side innovation is comparatively open.
Influence concentrates in older impact-modification patents
The most-cited records in the corpus are impact-modified and glass-clear polystyrene formulations built on styrene-butadiene block copolymers, some dating back well before 2015. Their citation counts reflect their role as foundational prior art for later formulation work, not evidence that they remain the most active filing target today.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to polystyrene films and microspheres, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Asahi Kasei Corporation | Asahi Chemical Industry Co., Ltd. | 8 |
| Asahi Kasei Corporation | Resonac Holdings Corporation | 6 |
| Cheil Industries Inc. | HONG SANG HYUN | 5 |
| Cheil Industries Inc. | BAE SU HAK | 5 |
| Dow Chemical Company | CHAUDHARY BHARAT I | 4 |
| Cheil Industries Inc. | AHN SUNG HEE | 4 |
| Dow Chemical Company | BARRY RUSSELL P | 3 |
| Cheil Industries Inc. | YANG JAE HO | 3 |
Only 10 co-assignee pairs appear across the corpus, and the strongest pairings involve the same handful of Japanese and Korean groups — a sign that most work here is filed by single assignees rather than through joint ventures or shared R&D agreements.
Assignee landscape and where activity has gone quiet
Filing activity in polystyrene film and microsphere patents is concentrated among a small group of established materials companies, several of which have gone quiet in the most recent tracked year even as the underlying claim territory they built remains in force.
The largest historical filers have stopped filing
BASF, Dow, Asahi Kasei, and other long-running assignees in this space show zero filings in the latest tracked year, despite being among the most active historically. That does not vacate their existing claims — it means the newest filing activity is coming from elsewhere.
Co-filing is the exception, not the rule
Only ten co-assignee pairings exist across 1,837 families, and the strongest of them cluster around a small number of Japanese and Korean corporate groups. Most assignees in this landscape file solo.
US, Europe, and Japan carry the bulk of filings
The United States, EPO, and Japan together account for the largest share of receiving-office activity, with China and the WIPO PCT route forming a smaller secondary tier. A filing strategy built only around one of the top three offices misses meaningful activity in the others.
| Assignee | Recent year | YoY |
|---|---|---|
| BASF SE | 0 | — |
| Dow Chemical Company | 0 | — |
| NOVA Chemicals Corporation | 0 | — |
| Asahi Kasei Corporation | 0 | — |
| Sekisui Plastics Co., Ltd. | 0 | — |
| Cheil Industries Inc. | 0 | — |
| General Electric Company | 0 | — |
| Kaneka Corporation | 0 | — |
Where to take this analysis
The filing and classification data point to specific next steps depending on whether the goal is freedom-to-operate or new filing strategy.
Map freedom-to-operate against the top-cited formulations
The five most-cited records concentrate around impact-modified and glass-clear styrene-butadiene formulations. Any new formulation claim should be checked against this cluster before drafting.
Run a freedom-to-operate checkInvestigate the shaping and equipment gap
B29C-classified shaping claims trail composition claims by nearly an order of magnitude. This is the most promising area for a first-mover claim if the underlying process work exists.
Explore white space in EurekaTrack why the largest filers went quiet
Several of the most historically active assignees show zero filings in the latest year. Understanding whether that reflects portfolio maturity, licensing strategy, or a pivot elsewhere changes how a competitor should respond.
Monitor assignee activityCommon questions about polystyrene film and microsphere patents
Filing activity is concentrated among a small set of established materials companies, including BASF, Dow, and Asahi Kasei, alongside Japanese and Korean groups such as Sekisui Plastics and Cheil Industries. These assignees built up their portfolios over the earlier part of the 2017–2026 window, and several show no new filings in the most recent tracked year, meaning their existing claims are largely in a maintenance phase rather than active expansion.
No — filing peaked in 2018 at 41 records and has declined since, dropping to 22 by the 2022 midpoint and to 7 in the most recent partial year. Because publication lags filing by roughly eighteen months, the most recent year understates true activity somewhat, but the multi-year decline through 2022 is a genuine slowdown, not just a reporting artifact.
The classification data shows a heavy skew toward polymer composition (C08L) and processing (C08J) claims, with shaping-focused B29C claims trailing at a fraction of that volume. Specific under-claimed areas include continuous suspension polymerization processes, in-line surface modification during extrusion, and equipment for monodisperse microsphere sizing — branches adjacent to the dense composition claims but not yet crowded themselves.
US20190112447A1, filed by Nucera Solutions, covers a specific process for making gray expanded polystyrene by introducing carbon black or graphite additives only after 20 to 60 wt% of the styrene monomer has converted to polystyrene, timed to control bead size and cell structure. It blocks that specific additive-timing window for gray EPS production, but it does not cover gray EPS generally, nor does it block additive introduction outside that conversion range or non-carbon-based colorant approaches.
C08L (polymer compositions) is the densest at 1,450 records, followed by C08J (polymer processing) at 866 and C08F (addition polymers) at 767. Anyone drafting a new composition claim in this space should expect to search against a large, well-established body of prior art in those three classes before assuming novelty.
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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.