What Is Spiral Fiber and Why It Outperforms Straight Fiber

We break down how a fiber's crimped, spiral structure affects the resilience and longevity of a filling.

Spiral, or crimped, fiber is polyester fiber given a three-dimensional curled shape during production, as opposed to straight fiber, which stays even along its entire length.

How the crimp is formed

The crimp is imparted to the fiber by the carding machine during one stage of production: the fiber is opened and takes on a stable spiral structure that holds for the product's entire service life.

How shape recovery works

The crimped structure creates countless tiny air pockets between fibers. When the filling is compressed — someone sitting on a cushion, or a toy being squeezed — those air pockets temporarily shrink. Once the load is removed, the spiral structure unwinds and returns the fiber to its original volume.

The limitation of straight fiber

Straight fiber doesn't have this springy structure. After compression it flattens and stays that way, and volume recovers more slowly and incompletely. Over time, a product filled with straight fiber loses its fullness faster than one filled with spiral fiber.

What this means for the finished product

• Pillows and sofas stay fuller for longer after regular use.
• Soft toys recover their shape faster after being squeezed or hugged.
• Mattresses filled this way distribute load more evenly over their service life.

Every fiber in our lineup — from 1D to 15D — combines a spiral structure with silicone treatment. That combination is exactly what separates a filling that holds its shape for years from one that flattens within months.