Description: Sample of white acrylic staple fibre produced under the tradename Zefran. Zefran was first produced in 1958 and is described as nitrile alloy. Zefran was unusual among acrylic fibres of the period in that dyes designed for regenerated cellulose fibres could be applied to it.
Acrylic fibres were first produced in 1941, by Dupont. Orlon was the first acrylic fibre to be produced commercially, initially as a filament but more successfully in the mid 1950s as a staple fibre.
Acrylic and modified acrylic fibre is produced by polymerising acrylonitrile (produced by reacting petroleum polypropylene and ammonia). Modified acrylic fibres are copolymers of acrylonitrile and another compound such as vinyl acetate, vinyl chloride, styrene, acrylic ester or acrylamide. The polymer is precipitated in water with a catalyst such as ammonium persulphate. The precipitate is then dissolved to form a spinning solution which can be wet or dry spun. Wet spinning involves pushing the solution through fine nozzles into a tank of containing a liquid chemical which causes the streams of spinning solution to set into filaments.
Zefran was used in knitted and woven clothing on its own or as a blended fibre.