Mushroom-type hook strip for a mechanical fastener

A method of continuously forming a smooth hook strip for a hook-and-loop type mechanical fastener consisting essentially of:

• a) providing a web backing having an array of upstanding substantially uniformly spaced thermoplastic projections which web backing and projections are formed of the same thermoplastic material, the thermoplastic material having a flow temperature, each projection having a stem portion and a top portion, said projection having a given first cross-sectional dimension, and height, said web backing and projections combined having a given second height;
• b) providing a gap formed by a first surface and a second surface, the gap being less than the second height, a first surface being heated to a temperature above the flow temperature of the thermoplastic material forming the projections;
• and
• c) moving the web backing into and through the gap such that the thermoplastic material forming the top portion of the projections are deformed, such that the projections have a second cross-sectional dimension and height which height is less than the first height and which second cross-sectional dimension is larger than the first cross-sectional dimension, by the heated surface under pressure, providing hooks with upstanding stem portions and hook heads having a smooth upper surface.