Thermal impulse bonding of thermally sensitive laminate barrier materials

Abstract

Thermal impulse heat welding, or “bar sealing”, is used to bond thermally sensitive laminate barrier materials such that they will pass AAMI level 4 testing (ASTM 1670 and 1671-b). In bar sealing, overlapping layers of thermally sensitive laminate barrier materials are melted and fused together to create a substantially solid bond at and/or adjacent the surface. No substantially un-melted areas remain within the fused bond area on the surface.

1 . A surgical gown having an AAMI critical zone comprising a tie cord bar sealed to said gown at a bond in said critical zone wherein said bond passes AAMI level 4 testing. 
     
     
         2 . The gown of  claim 1  wherein said bond is made at a temperature between 240 and 320° F. (116 and 160° C.), a pressure between 40 and 80 psi (276 and 552 kPa) and a dwell time between 0 and 5 seconds. 
     
     
         3 . The gown of  claim 1  wherein said bond is made at a temperature between 260 and 290° F. (127 and 143° C.), a pressure between 50 and 60 psi (345 and 414 kPa) and a dwell time between 1 and 3 seconds. 
     
     
         4 . The gown of  claim 1  wherein said gown comprises a polyolefin microfiber layer. 
     
     
         5 . The gown of  claim 4  wherein said gown further comprises a filled film. 
     
     
         6 . A surgical gown having a tie cord and a tie cord bond area where said tie cord is bonded to said gown, wherein said tie cord bond area passes ASTM test 1671-b. 
     
     
         7 . A thermal bond for a film layer-containing thermoplastic fabric wherein said bond joins a thermoplastic material to said fabric to form a fused bonded area, without bonding to said film layer. 
     
     
         8 . The bond of  claim 7  wherein no un-melted areas remain within the fused bond area on the surface. 
     
     
         9 . The bond of  claim 7  wherein said film layer-containing thermoplastic fabric further comprises a filler within said film layer. 
     
     
         10 . The bond of  claim 7  wherein said thermal bond is produced substantially at or adjacent a surface of the film layer-containing thermoplastic fabric while avoiding degradation of said film layer in an interior region of said fabric. 
     
     
         11 . The bond of  claim 7  wherein said thermal bond has a width of between 0.32 and 1.75 cm. 
     
     
         12 . The bond of  claim 11  wherein said thermal bond has a length of between 2.54 and 76 cm. 
     
     
         13 . The bond of  claim 7  wherein said film layer-containing thermoplastic fabric is a spunbond/film laminate. 
     
     
         14 . The bond of  claim 13  wherein said spunbond layer is made from polyethylene, polypropylene or an ethylene-propylene copolymer. 
     
     
         15 . The bond of  claim 13  wherein said film layer is a stretch-thinned film. 
     
     
         16 . The bond of  claim 15  wherein said film layer further comprises calcium carbonate. 
     
     
         17 . The bond of  claim 15  wherein said film is a an ABA film. 
     
     
         18 . The bond of  claim 17  wherein said film is heated to a temperature no higher than 5 degrees ° C. below the melting point of the B layer in the film. 
     
     
         19 . The bond of  claim 18  wherein said film is stretched to about 250% to 500% of its unstretched length. 
     
     
         20 . The bond of  claim 18  wherein said film is stretched to about 300% of its unstretched length.