In this landscape it means containers formed from moulded pulp or fibre — the same category as egg cartons or moulded pulp trays — that carry a claimed barrier property against grease or water, or a claim to being PFAS-free. The search combines molded-pulp terminology with barrier-coating language at the title, abstract or claim level, then restricts results to IPC classes covering pulp compositions, moulded fibreboard, plastic articles and packaging containers. It excludes general moulded-pulp patents that make no barrier claim, and excludes general barrier-coating patents applied to substrates other than moulded pulp.

The assignee ranking is short, spanning materials and packaging companies alongside at least one university filer, and no single organisation dominates by a wide margin given the corpus totals only 23 families. Recent-year momentum data shows zero new filings from every tracked assignee in the latest year, which likely reflects publication lag rather than an actual halt. Anyone tracking this space should watch the ranking update as 2025–2026 filings clear the roughly 18-month publication delay.

Based on published records, filings rose from zero in 2017 to a peak of 17 in 2022 and have not matched that level since, which reads as flat-to-declining rather than a growth curve. Because publication lags filing by around 18 months, the most recent one to two years are understated and should not be read as a real drop-off yet. A fair read is that one concentrated filing push happened around 2022, and whether a second wave follows is not yet visible in the data.

Only 2 of 23 records classify under C09D, the coatings and paints IPC subclass, even though the search targeted barrier-coating language directly. This suggests that in practice, applicants are claiming barrier performance as a property of the pulp furnish or the moulding process — captured under D21H and D21J — rather than as an independently claimed coating layer. For drafting purposes, that means prior art search and freedom-to-operate work in this space cannot stop at the coatings classification; pulp-composition and forming-process claims carry most of the relevant art.

The clearest gaps sit in sub-areas that fall inside the searched IPC classes but show little dedicated claim density: PFAS-free barrier formulations claimed independently of pulp furnish, localized or non-uniform coating deposition methods, and grease-resistant additives blended into the pulp itself rather than applied as a surface layer. These are technically specific enough to support a first claim, but any filing there should be checked against the most-cited records in this corpus, which already cover coating methods on hollow moulded-pulp containers. The small size of the overall dataset (23 families) also means white space here is provisional — a handful of unpublished filings could close a gap quickly.