One assignee leads with 17 records in this 79-record dataset, well ahead of the fifth-ranked company at 5 records and the tenth-ranked at 3. The ranking covers 36 companies total and is the complete set returned for this search, not a top-50 or top-100 shortlist. Filing activity from the leader concentrates in catalytic cracking and high-silica zeolite formulations rather than standalone separation hardware, which lines up with the wider dataset’s tilt toward B01J catalysis claims.

Filings peaked at 5 in 2021 and had fallen to 1 by 2024, an 80% decline over that three-year window. 2024 is the last year in this dataset that can be treated as complete, because publication typically lags actual filing by around 18 months, so 2025 and 2026 figures are still filling in. Based on the complete data through 2024, momentum has clearly cooled from its 2021 peak, though it would be premature to describe the trend beyond that year.

US5380690A claims a cracking catalyst combining clay, inorganic oxides and a zeolite blend of REY or high-silica Y zeolite with phosphorus- and rare-earth-containing high-silica pentasil zeolite, aimed at improved hydrothermal stability and light-olefin yield. It is the second most-cited record in this dataset at 225 citations, which signals strong influence over later catalytic cracking filings rather than automatic blocking power over every hydrophobic adsorbent application. Whether it blocks a specific new filing depends on how closely that filing’s zeolite composition and process claims overlap with the specific mixture ratios and pentasil structure recited here — a claim-by-claim comparison is the only reliable way to check.