One assignee leads this landscape with 92 of the 184 records tracked, far ahead of the fifth-ranked company at 9 records and tenth place at 3. That leader’s portfolio is built substantially on light- and radiation-activation chemistry with a strong university co-assignment, rather than on mechanical glazing hardware alone. Anyone assessing freedom to operate in structural bonding or encapsulation should treat that portfolio as the first stop, since the rest of the 55-company ranking is comparatively thin and spread across single- and low-digit filers.

Filing activity peaked at 16 records in 2017 and has fallen sharply since; the tracked cohort dropped from 2 filings in 2021 to 0 in 2024, a full -100% change over that window. That is the most recent period that can be read as complete, because publication lags filing by roughly 18 months and so 2025 and 2026 figures are still filling in. It would be premature to call the field dead on the strength of the two most recent years alone, but the 2021-2024 trend itself is a genuine and complete decline.

Urethane bonding refers to two-component urethane adhesives used to structurally bond glass panes into a vehicle body or frame, a method with roots going back to filings such as the widely-cited US5853895A. In this landscape it sits alongside primer application, cure time control and dimensional tolerance claims, which together determine whether a bonding chemistry can actually be deployed on a production line rather than just demonstrated in a lab. The search scope ties urethane bonding claims specifically to these process-level requirements.