Why a cut loop becomes a hook
The key is where the loop is cut. A loop of plastic filament rises from the fabric and bends back toward its base. Slice through its crown, and the two sides become short, upright legs; their cut ends form the tips that catch neighboring loops. The cut does not need to produce a curved, metal-like hook. A small projection is enough to snag the softer, flexible loops on the mating strip.
A heated blade can both sever the filament and soften its edge, helping the newly formed tips hold their shape. The precise machinery varies, but the design principle is simple: make one surface that presents many catches and another that offers many loops.
A fastener made of thousands of small catches
When the strips are pressed together, hooks enter loops at many points. Each connection is weak on its own, but the crowd of connections makes the fastening hold. Pulling the strips sideways—along the plane of the fabric—tends to keep many hooks engaged. Peeling one strip back from an edge releases them in succession, which is why the fastener can be opened without tearing the whole patch apart.
That difference also explains why the material is useful for adjustable closures: it can hold across a broad area, yet separate locally when someone lifts an edge. The “handshake” is persistent because countless tiny catches share the load, not because any single hook locks permanently.
