Description: Sample of white staple fibre in a glass jar with a plastic lid - acrylic staple fibre produced under the tradename Tacryl. Tacryl was first produced in the 1950s and is described as polyacrylic nitrile fibre.
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.
Acrylic and modified acrylic fabrics are are used for clothing, often blended with wool in knitwear; domestic furnishings; synthetic fur; and industrial applications such as filters where chemical resistance is needed.
Various forms of Tacryl may exist, one form is a copolymer of acrilonitrile and 8 percent methyl acrylate and triacrylohydrothiazine. Modacrylic contains 35 to 85 percent acrylonitrile whereas acrylic must contain over 85 percent although acrylonitrile copolymers with over 85 percent acrylonitrile are sometimes referred to as modified acrylic.