Patent ID: 6558602
Filing Date: 2003-05-06
Classification: A44B,B29C,Y10T

Abstract:
A method of continuously forming a smooth hook strip for a hook-and-loop type mechanical fastener comprising: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 without any supports for the projections 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, said hooks formed by the gap having a height of from 0.5 to 5 mm and the ratio of the height of the hook to the diameter of the stems being from 2:1 to 10:1.