The assignee ranking in this dataset spans specialty chemical manufacturers, ceramics and refractories companies, a semiconductor materials firm, and university research groups, without a single entity dominating the full 169-family set. Ownership is fragmented rather than consolidated, which matters for licensing strategy: there is no single dominant portfolio to negotiate against. None of the leading assignees tracked here show filings in the most recent year, which is consistent with the broader plateau in the filing trend rather than a company-specific pullback.

Filing peaked in 2019 at 18 families and had fallen to a single filing by the 2022 midpoint, indicating a plateaued rather than growing field. That said, publication typically lags actual filing by around eighteen months, so the most recent one to two years in any dataset understate real activity. The honest read is that the foundational claim space around core h-BN composition and processing is largely staked out, and new activity is incremental.

US10781351B1, held by Louisiana Tech Research Corporation, claims a porous h-BN material formed by depositing h-BN onto a catalyst foam via atmospheric-pressure chemical vapor deposition, then encapsulating and wet-etching to partially remove the foam. It blocks that specific combination of foam-templated CVD deposition followed by encapsulation and edge wet-etch, not h-BN thermal fillers generally. Work using different templating methods, different deposition pressures, or different catalyst removal chemistry sits outside its literal claim scope, though a careful claim-chart comparison is needed for any specific process.

The clearest gaps sit in the subclasses with the lowest filing density relative to core chemistry: semiconductor-grade dielectric integration (H01L, 21 records) and catalysis-related process claims (B01J, 19 records), both well below the 118 records concentrated in core C01B composition claims. Specific under-claimed branches include h-BN/polymer interface bonding chemistry, thermal filler loading optimisation in composite formulations, and scalable atmospheric-pressure CVD foam templating beyond the single patented example in this dataset. These are the areas where a first claim is less likely to collide with dense prior art.

Highly concentrated in core inorganic chemistry: C01B (non-metallic elements and inorganic compounds) accounts for 118 of the 169 tracked records, more than double the next largest class, C08K polymer additives at 45. Coating deposition (C23C, 40), ceramics (C04B, 35), and miscellaneous materials applications (C09K, 34) form a middle tier, while semiconductor devices (H01L, 21) and catalysis (B01J, 19) are the smallest. This distribution shows that most protected ground is in the material itself rather than in how it is deposited, formulated into polymers, or integrated into devices.