Filing history in this corpus is led by a small set of materials and chemicals groups, with Zeon Corporation and Japan's AIST standing out through a nine-family co-filing partnership on CNT fibre production. LG Chem also shows a notable academic partnership with Sogang University Research Foundation. No single assignee dominates the full 448-family set; instead, activity is spread across a handful of established filers plus a long tail of single-filing entrants, which is typical for a materials technology with broad industrial application rather than one locked to a single end product.

Filing activity peaked in 2018 at 43 families and had eased to 38 by the 2022 midpoint, with the partial 2026 count continuing that softer trend. Because publication lags filing by roughly eighteen months, the most recent year always understates true activity, but the multi-year pattern from 2018 onward is flat to declining rather than growing. This suggests the core composition and synthesis claim space is largely occupied, with new activity more likely to appear in application-layer filings than in fundamental material claims.

US9802823B2, assigned to Zeon Corporation and published in 2017, covers a carbon nanotube fiber made from an assembly of nanotubes that include ones with at least partially collapsed structures, plus a production method that spins a CNT dispersion liquid containing a dispersant and solvent through extrusion. It is both a composition claim on the collapsed-structure fiber and a process claim on the extrusion-spinning method used to produce it. Anyone producing CNT fiber by a similar collapsed-structure-plus-extrusion route should review this filing closely as part of freedom-to-operate work.

Within this corpus, battery and fuel-cell applications (H01M) carry the lowest filing count among the tracked application codes, at 44 families against 376 in the core non-metallic-compound composition code. Application areas such as selective-transport membranes and biscrolled fibre fabrication also show comparatively thin coverage relative to the composition core. That gap does not guarantee those areas are technically easy — it means fewer claims have been staked there yet, which is the more useful signal for deciding where a novelty search is worth running first.

The United States receives the largest share of filings in this corpus at 194, followed by the European Patent Office at 117 and the WIPO PCT route at 33. India, China and Australia follow at smaller volumes. The heavy US and EPO weighting suggests filers are prioritising the two largest examination jurisdictions with strong materials-science patent practice, with PCT filings used to preserve international rights before committing to national phase elsewhere.