In this corpus, a biolubricant claim typically covers a lubricant base stock or finished formulation derived from a renewable feedstock such as vegetable oil, combined with a technical limitation like biodegradability, oxidative stability or a defined viscosity index. It is not enough for a filing to mention a plant-derived ingredient in passing; the claims need to tie that ingredient to a measurable lubricant performance property. This is why the search scope here combines composition terms with property terms like oxidative stability and seal compatibility rather than searching on biolubricant alone.

The filing trend shows a peak of 25 families in 2019 followed by a drop to 12 by 2022, and it has not recovered since. This pattern is consistent with a field where the main formulation routes — ester base stocks, polyalphaolefin blends, common additive packages — were already well claimed by the late 2010s, leaving less open ground for new filings. Bear in mind that the final one to two years of any patent trend are always undercounted because of publication lag, so the true 2025-2026 picture will only become clear over the next year or so.

China leads with 100 of the 305 families in this dataset, followed by the European Patent Office at 59 and the United States at 38, with Japan, WIPO/PCT and Australia further behind. That distribution means a clearance or landscape exercise focused only on US and European registers would miss the single largest filing destination. Anyone assessing freedom to operate in this space should treat Chinese filings as a first-order check, not an afterthought.

US11492567B2 claims a specific three-step process for producing a biolubricant from vegetable oil: esterification with a branched aliphatic alcohol, epoxidation of the resulting esters, and a nucleophilic substitution step using a second branched aliphatic alcohol, with a worked example built on a ricinoleic fatty acid backbone. It blocks that particular reaction sequence and the resulting product class, not every route to a vegetable-oil-derived biolubricant. A process that skips the epoxidation step, or that uses a different substitution chemistry entirely, sits outside what this claim covers.

The IPC composition shows filing activity concentrated almost entirely in C10M and C10N, with only thin coverage in adjacent areas like C07C acyclic compounds, C11C fatty acids and C08F addition polymers. That imbalance suggests under-claimed ground in areas such as ester base stock seal-compatibility formulations, bio-based polyalphaolefin blends, and low-temperature oxidative stability additives derived from fatty acid chemistry. None of these are guaranteed open — they simply carry fewer families relative to the core claim space and warrant a targeted prior-art check before drafting.