Crease is a fold in fabric introduced unintentionally at some stages of processing. Crease or crushing of textile material is a complex effect involving tensile, compressive, flexing and tensional stresses. Crease recovery is a fabric property which indicates the ability of fabric to go back to its original position after creasing.
Crease recovery is a measure of creases resistance, specified quantitatively in terms of crease recovery angle. To measure this, the popular instrument is Shirley crease recovery tester. The instrument consists of a circular dial which carries the clamp for holding the specimen. Directly under the centre of the dial there is a knife edge and an index line for measuring the recovery angle. Crease recovery is determined depending upon this recovery angle. If the angle is 0o then recovery is zero and if the angle is 180o then recovery is full. Crease recovery depends on the construction, twist of yarn, pressure, time etc. Usually crease recovery is more in warp way than in weft way. This is because warp yarns are well in quality, strength, treated with sizing, kept in more tension during weaving etc.
Related Standard - Iso 2313, Aatcc 66, Bs En 22313 M&s P22