Recycled Polyester Fiber Patents: Leaders, Trends & White Space 2026
- Filings peaked in 2021 at 10 families and have declined since, with the most recent year showing no new filings — a cooling signal after a mid-decade push.
- Japan and South Korea dominate the receiving offices with 22 and 11 records respectively, versus 7 each for China and the United States, showing this is still largely an East Asian filing pattern.
- Three assignees co-file repeatedly with pairwise overlaps of 7 each, pointing to a tight cluster of related entities rather than a fragmented field of unrelated single filers.
Filing growth compares 2021 (10 records) with 2024 (3) — 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 57 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks 57 patent families filed between 2015 and mid-2026 that describe recycled polyester and rPET functional fiber — spinning, additive formulation and post-consumer bottle-chip processing routes captured under IPC classes D01F6/62, C08J11/24 and D01F6/92. The search string isolates records that explicitly claim recycled polyester or recycled PET fiber and filament, rather than virgin-polyester fiber work that happens to mention recyclability in passing.
Because publication lags filing by roughly 18 months, the apparent drop-off in the most recent year understates real filing activity; the 2021 peak and subsequent decline through 2022 are the more reliable read on where the field's momentum has actually gone.
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Filing trends and technology composition
Two views of the same 57-family dataset: filing activity over time, and how records distribute across the IPC subclasses that touch recycled polyester fiber processing.
A 2021 peak followed by decline
Filings rose from 4 in 2017 to a peak of 10 in 2021, then fell back — 2022's count of 2 sits well below the peak, and the trend line has not recovered since, though the final year or two is undercounted due to publication lag.
Concentrated in filament and spinning classes
D01F (chemical filament and fibre features) covers 56 of 57 records, essentially the entire dataset, with D01D (man-made filament spinning) a distant second at 25. Additive-side classes like C08G, C08J and C08K each register only single digits, suggesting most claim activity sits on fiber structure and spinning process rather than on polymer or additive chemistry.
Shares are the percentage of the 57 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Recycled Polyester Fiber Functional Fiber with Eureka
This page is one run against one query. Ask Eureka your own question about recycled polyester fiber functional fiber and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art
US20200270416A1 — Recycled Polyester Fiber
A recycled polyester fiber made by melt spinning a raw material of 95.0–99.99 wt% recycled polyester pellet from recycled bottle chip and 0.01–5.0 wt% titanium dioxide slurry, the slurry itself specified down to bio-oil carrier, dispersant, antioxidant and dye ratios.Filed by NAN YA PLASTICS CORPORATION, published 2020-08-27.
View full filing| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | CN104630928A | 一种基于石墨烯增强阻燃再生聚酯短纤维的制备方法 | 58 |
| 2 | JP2002054026A | Method of producing flame-retardant recycled polyester fiber utilizing recovered polyester | 38 |
| 3 | JP2004100087A | Recycled polyester fiber | 32 |
| 4 | JP2005206966A | Recycled polyester fiber | 25 |
| 5 | JP2002235243A | Recycled polyester fiber for industrial material | 22 |
| 6 | CN103215686A | 一种无卤阻燃再生聚酯纤维的制备方法 | 19 |
| 7 | JP2006336122A | Wet heat-resistant recycled polyester fiber | 18 |
| 8 | JP2006070419A | Flame-retardant recycled polyester fiber | 14 |
| 9 | KR1020120070858A | Recycled polyester fiber having UV blocking property and flame retardant, and manufacturing method thereof | 10 |
| 10 | JP2006022435A | Fiber product | 10 |
Citation counts reflect influence within the searched corpus and favour older filings; they are not a measure of current commercial importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Reading the filing trend, IPC split and citation pattern together points to a field that built out its core spinning and additive claims early, then slowed.
Activity has cooled since 2021
The filing count climbed steadily from 4 in 2017 to a peak of 10 in 2021, then dropped sharply — 2022 shows just 2. Read the last year or two cautiously given an 18-month publication lag, but the multi-year decline before that is real.
Fiber structure claims dominate
Almost every record in this dataset touches D01F, the chemical filament and fibre features class. D01D spinning process claims are the second-largest group at 25, while additive and polymer chemistry classes (C08G, C08J, C08K) each sit in single digits.
East Asian filing dominates
Japan and South Korea together account for 33 of 57 records, more than China (7) and the United States (7) combined. This is a field where the earliest and densest claim activity sits with Japanese and Korean filers.
A tight cluster of related filers
Six co-assignee pairs appear in the dataset, but three of them share the same strength of 7 co-filed families, all involving the same small group of related entities — a sign of corporate affiliation rather than independent convergence on the same claims.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to recycled polyester fiber functional fiber, with the prior art for and against each one.
Who holds the claim space
Filing activity concentrates among a small set of Japanese and Chinese assignees, several of them clearly affiliated, with momentum flat or negative for all of the most active filers in the latest year.
Momentum has stalled at the top
Every one of the most active assignees in this dataset — including the Nippon Ester / Unitika-affiliated cluster and major fiber producers such as Toray — shows zero filings in the latest year, with several posting a full -100% year-on-year drop. None show renewed acceleration.
Related entities file together
The strongest co-assignee relationships in the dataset all involve the same small cluster — Nippon Ester, Unitika Trading and Unitika itself — each pair sharing 7 co-filed families, consistent with a coordinated corporate filing strategy rather than arm's-length competition.
Established fiber makers hold ground
Beyond the Japanese cluster, large-scale synthetic fiber producers including Jiangsu Hengli Chemical Fibre and Toray (plus its chemical subsidiary) also appear among the more active assignees, indicating the space isn't limited to specialist recyclers.
| Assignee | Recent year | YoY |
|---|---|---|
| Nippon Ester Co., Ltd. | 0 | -100% |
| Jiangsu Hengli Chemical Fibre Co., Ltd. | 0 | — |
| Unitika Trading Co., Ltd. | 0 | -100% |
| Unitika Ltd. | 0 | -100% |
| Toray Industries, Inc. | 0 | — |
| Unitika Fibers Ltd. | 0 | — |
| Nan Ya Plastics Corporation | 0 | — |
| Toray Chemical Korea Inc. | 0 | — |
Where to take this analysis
The filing and citation data point to specific next questions for anyone deciding where to file or where to license.
Map the additive-chemistry gap
C08G, C08J and C08K claims sit in single digits against 56 D01F records — a first check is whether that gap reflects genuine white space or simply claims filed under different classification.
Explore additive claims in EurekaTrack the Nippon Ester / Unitika cluster
With three pairs of affiliated assignees sharing 7-family overlaps and zero recent filings, watch whether this cluster resumes activity or whether newer entrants pick up the claim space.
Monitor assignee activity in EurekaWatch the flame-retardant sub-branch
The single most-cited record in the corpus is a graphene-reinforced flame-retardant recycled polyester fiber process — a strong citation signal for a narrow, still-thin filing area.
Review cited prior art in EurekaCommon questions
Filing activity concentrates among a cluster of Japanese assignees — Nippon Ester, Unitika Trading and Unitika — who repeatedly co-file with each other, alongside larger-scale fiber producers like Toray and Jiangsu Hengli Chemical Fibre. All of the most active assignees show zero filings in the most recent year, which means the current leadership reflects historical filing rather than active present-day expansion. A freedom-to-operate check should still start with this cluster given the density of their existing claims.
The dataset shows filings peaking at 10 in 2021 and falling to 2 by 2022, with no recovery since. Part of the apparent decline in the final year or two is a publication-lag artefact, since patent applications typically publish around 18 months after filing. But the multi-year decline from the 2021 peak through 2022 predates that lag window and likely reflects a real slowdown in new claim activity in this specific IPC combination.
The core class is D01F (chemical filament and fibre features), which covers 56 of the 57 records in this dataset — essentially universal coverage. D01D (man-made filament spinning) is the second most common at 25 records. Smaller counts appear in D02G (yarn texturing), B29B (plastics preparation), D01G (fibre preliminary processing) and additive-chemistry classes C08G, C08J and C08K, each in single digits.
Japan leads as a receiving office with 22 records, followed by South Korea at 11. China and the United States each account for 7, with the European Patent Office at 4 and the Philippines at 3. This distribution shows the field's densest claim activity has historically sat with Japanese and Korean filers rather than being evenly spread across major markets.
US20200270416A1, filed by Nan Ya Plastics, claims a melt-spun recycled polyester fiber made from 95.0–99.99 wt% recycled bottle-chip pellet combined with 0.01–5.0 wt% titanium dioxide slurry, with the slurry composition itself specified down to bio-oil carrier, dispersant, antioxidant and dye ratios. It does not block recycled polyester fiber generally, or even titanium dioxide additive use broadly — its claim scope is tied to those specific weight-percentage ranges and slurry formulation. Formulations outside those ranges, or using different additive carriers, sit outside this particular claim's literal scope, though a full clearance check should compare against the whole dependent claim set.
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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.