Patent Leaderboard
USPTO Patent Rankings Data through Dec 31, 2025

Meta-phenylenediamines, process for preparation thereof, intermediate compounds and use of these meta-phenylenediamines as couplers for the oxidation dyeing of keratinous fibres and especially human hair

US Patent 4960432 · Granted Oct 2, 1990

Assignee

Inventors

View full patent text on Google Patents →