Polyester staple fibre (PSF) is widely used in filling materials and nonwoven products, and one of the most important structural properties is crimp.
Crimp refers to the natural waviness or curl of the fibre. It directly affects fibre performance in terms of bulkiness, resilience, and processing behavior.
What Is Crimp in PSF?
Crimp is the three-dimensional waviness formed in the fibre during the production process, especially in conjugated hollow fibres.
It is typically measured by:
Crimp number (number of waves per unit length)
Crimp stability (how well the crimp holds after processing)
Higher crimp means more curls per fibre length.
How Crimp Is Formed?
In bi-component hollow conjugated PSF, crimp is created due to the different shrinkage rates of two polymers.
When the fibre is heated:
One side shrinks more than the other
This imbalance causes the fibre to bend and form a spiral or wave
This structure is essential for achieving high loft and elasticity.
To be continued...
