How hook-and-loop fasteners are made

Hook-and-loop tape is woven with tiny loops, and one of the two strips then has its loops cut into hooks.

stations: 5
things upstream: 12
raw sources: 5
steps from the ground: 6

The short version

Nylon yarn is woven into a flat tape with a field of tiny raised loops. Stiff monofilament goes into the hook tape, and softer fibers into the loop tape. Heat sets the loops so they hold their shape. On the hook half, a blade snips each loop on one side, leaving a hooked stem.

Spin the nylon yarn

Nylon is melted and forced through fine holes into thread. Hook tape uses a stiff single-strand monofilament. Early cotton versions frayed and wore out quickly, which is why the inventor moved to synthetic fiber.

Goes in
Nylon
Weave a looped tape

A loom weaves a flat base strip and raises rows of tiny loops from its face. Mechanizing this took years, since each loop has to form in the same way.
Heat-set the loops

Heat fixes the shape of the woven monofilament, often under infrared light. The nylon remembers the shape, so the loops stand up and stay open.
Snip loops into hooks

On the hook side, reciprocating blades shear each loop across the width of the tape. Each loop becomes a single stiff hook that can catch the soft loops of the other half. On the other tape the loops stay uncut.
Slit and reel the tape

Wide woven tape is slit into narrow strips, and wound on reels for sewing or stick-on backing.

End of the lineHook-and-loop fastener

Worth repeating

George de Mestral conceived hook-and-loop fasteners in 1941 after studying burdock burrs that stuck to his dog's fur.
It took ten years to build a mechanized process that worked.
When the patent expired in 1978, cheap imitations from Taiwan, China and South Korea flooded in.