Split hook fastener

Abstract

The present invention provides a method for forming preferably a unitary polymeric hook fastener comprising a flexible backing, and a multiplicity of spaced hook elements projecting from the upper surface of the unitary backing. The hook elements each comprise a stem portion attached at one end to the backing, and a head portion at the end of the stem portion opposite the backing. The head portion projects in different directions for some adjacent hook members which adjacent hook members each have a flat face which flat faces are mutually opposing in face to face relation.

1 . A method of forming a hook fastener comprising providing a hook fastener strip having a thermoplastic base layer with integral upstanding hook elements having stem portions and head portions with loop engaging overhangs, cutting at least some of the hook elements along the head portion and down to the stem portion substantially to the base layer and orienting the base layer so as to separate the cut hook elements.  
     
     
         2 . The method of forming a hook fastener of  claim 1  wherein the hook members having a flat face are in opposing face to face relation with the flat face of another hook member having a flat face.  
     
     
         3 . The method of forming a hook fastener of  claim 1  wherein the film backing is oriented.  
     
     
         4 . The method of forming a hook fastener of  claim 3  wherein the film backing has a thickness of from 25 to 250 μm.  
     
     
         5 . The method of forming a hook fastener of  claim 3 , wherein the film backing has a thickness of from 50 to 150 μm.  
     
     
         6 . The method of forming a hook fastener of  claim 1  wherein the overhanging portions extend 0.01 to 0.3 mm.  
     
     
         7 . The method of forming a hook fastener of  claim 6  wherein the overhanging portions extend 0.02 to 0.25 mm.  
     
     
         8 . The method of forming a hook fastener of  claim 6  wherein the overhanging portions extend 0.02 to 0.2 mm.  
     
     
         9 . The method of forming a hook fastener of  claim 1  wherein the hook members have a height of from 0.1 to 2 mm.  
     
     
         10 . The method of forming a hook fastener of  claim 1  wherein the hook members and hook elements on the backing have a density of from 25 to 500 per square centimeter.  
     
     
         11 . The method of forming a hook fastener of  claim 1  wherein at least a portion of the hook engaging portion extends at an angle (α) of from 1° to 90° from a flat face of the hook member.  
     
     
         12 . The method of forming a hook fastener of  claim 1  wherein at least a portion of the hook engaging portion extends at an angle (α) of from 1° to 89° from a flat face of the hook member.  
     
     
         13 . The method of forming a hook fastener of  claim 1  wherein at least a portion of the hook engaging portion extends at an angle (α) of from 5 to 85° from a flat face of the hook member.  
     
     
         14 . The method of forming a hook fastener of  claim 1  wherein the hook fastener includes hook elements without flat faces.  
     
     
         15 . The method of forming a hook fastener of  claim 14  wherein the hook members having flat faces comprise at least 50 percent of the hook structures.  
     
     
         16 . The method of forming a hook fastener of  claim 15  wherein the hook members having flat faces comprise at least 90 percent of the hook structures.