Abstract: Two strip materials from which portions may be severed and used together as a releasably engageable fastener. Each strip material comprises a bonding layer in which are embedded a plurality of U-shaped monofilaments. Each U-shaped monofilament includes two headed stem portions adapted to engage the headed stem portions of the other strip material, and the monofilaments are rectangularly arrayed, and spaced to provide a number of headed stem portions per unit length that are different from and not a multiple of or evenly divisible by the number of headed stem portions per unit length on the other strip material in any direction so that upon engagement the rows of headed stem portions of one strip material cannot readily slip between the rows of headed stem portions on the other.

Abstract: A fastener comprising two articles adapted for releasable engagement. At least one of the articles comprises a backing with a non-fibrous polymeric surface bonding layer in which are bonded a plurality of U-shaped flexible resilient monofilaments of longitudinally oriented polymeric material. Each of the monofilaments includes two stem portions projecting from the surface bonding layer and terminating in enlarged heads having outer cam surfaces adapted to engage the other article.

Abstract: A method for forming a strip material useful as part of a fastener. The method steps comprise moving two backing layers from opposite directions around guides and away from the guides in parallel paths, feeding monofilaments between the guides, pressing the monofilaments first into engagement with one and then the other of the backing layers on the guides so that lengths of the filaments extend normally between the backing layers along the parallel paths, severing those normally extending monofilaments halfway between the backing layers, and heating the newly severed terminal ends of the monofilaments to form heads.