A synthetic paint brush bristle made by extruding an acid solution of casein. The fiber is then stretched and dipped in formaldehyde for hardening. Casein bristle brushes have good paint-carrying capacity and good wear resistance (Brady 1971).
Burns with odor of burnt hair.
Hazards and Safety
Burns slowly and brightly in air but extinguishes with removal of flame source.
G.S.Brady, Materials Handbook, 10th edition, McGraw-Hill, New York, 1971.