Reclosable fasteners for plastics bags and the like

Abstract

A reclosable fastener or zipper comprises interengageable male and female profile members ( 12, 16 ), each provided on a base ( 13, 17 ). One or both vases is/are provided with a lateral flange ( 18, 20, 22, 24 ). One or more of such flanges is/are provided with a pair of spaced, shallow convexities ( 28 ) with a layer of sealant material ( 30 ) co-extruded into the zone or zones between the convexities.

1 . A reclosable fastener comprising interengageable male and female profile members, each provided on a base, and with one base being connected to a lateral flange, wherein said flange is provided with a pair of spaced, shallow convexities with a layer of sealant material co-extruded into the zone between the convexities.  
     
     
         2 . A reclosable fastener comprising interengageable male and female profile members, each provided on a base, and with at least two lateral flanges connected to one base or to the two bases, wherein one or more of said flanges is provided with a pair of spaced, shallow convexities with a layer of sealant co-extruded into the zone or zones between the convexities.  
     
     
         3 . A reclosable fastener according to  claim 2 , in which each base is connected to two respective lateral flanges.  
     
     
         4 . A reclosable fastener according to any preceding claim, in which the layer of sealant material is of the order of 3 mm in lateral width.  
     
     
         5 . A reclosable fastener according to any preceding claim, in which the layer of sealant material is of the order of 0.07 mm in thickness.  
     
     
         6 . A reclosable fastener according to any preceding claim, in which the thickness of the layer of sealant material is of the order of 44% of the combined thickness of the sealant and flange.  
     
     
         7 . A reclosable fastener according to any preceding claim, in which the convexity which is nearer to the profile member has a greater lateral width than the convexity which is further from the profile member.  
     
     
         8 . A reclosable fastener according to any preceding claim, in which the thickness of the flange or flanges is less outwardly of the outer convexity than inwardly of the inner convexity.  
     
     
         9 . A reclosable fastener according to any preceding claim, in which one said base is connected by a hinge joint to a lateral flange or flanges.  
     
     
         10 . A method of extruding a reclosable fastener which comprises extruding a male profile member on a base and a female profile member on a base, with a lateral flange connected to one base and with a pair of, spaced, shallow convexities proud of the flange, and co-extruding a layer of sealant material into the zone between the convexities.  
     
     
         11 . A method of extruding a reclosable fastener which comprises extruding a male profile member on a base and a female profile member on a,base, with at least two lateral flanges connected to one base or to the two bases, and with a pair of spaced, shallow convexities on one or more of said flanges, and co-extruding a layer of sealant material into the zone or zones between the convexities.  
     
     
         12 . A method according to  claim 10  or  11 , in which in the said co-extrusion process the sealant material does not fill the zone or zones to the zone ends.