Other processes for obtaining cellulose, e.g. cooking cotton linters (obtaining fibres for spinning D01C);

Filing statistics

CPC D21C 5/00 belongs to the parent subclass D21C, which recorded 15,992 patent applications worldwide between 2013 and 2023. Annual filings declined from 1,472 in 2013 to 836 in 2023 (-43%), peaking at 1,804 applications in 2018. The most active applicants in class D21 are VOITH PATENT (1,857 applications), STORA ENSO (1,552 applications) and KEMIRA (1,173 applications).

Source: EPO PATSTAT, worldwide filings