Disposable diaper and process for making the same

Abstract

A disposable diaper has a covering member adapted to cover a wearer's crotch and waist regions. The covering member includes an elastically stretchable first layer and an inelastically stretchable second layer formed with a plurality of continuous fibers. The continuous fibers are fixed to the first layer in at least two bonding zones. The covering member presents a particularly large value of L/D, a ratio of a length L of each continuous fiber and a distance D in straight line between each pair of the adjacent bonding zones.

What is claimed is:  
     
         1 . A disposable diaper comprising an elastically stretchable covering member adapted to cover diaper wearer's crotch and waist regions and a liquid-absorbent core member sandwiched between a liquid-pervious sheet destined to come in contact with skin of said diaper wearer and said covering member, wherein: 
 said covering member consists of an elastically stretchable first layer and an inelastically stretchable second layer formed with a plurality of continuous fibers and said continuous fibers being fixed to said first layer in at least a pair of bonding zones spaced from each other so that L/D, i.e., a ratio of a length L of said continuous fiber extending between said pair of the bonding zones to a distance D in straight line between said pair of bonding zones is larger in a desired range of said covering member than in the remaining zone.    
     
     
         2 . The diaper according to  claim 1 , wherein said desired range is defined in a transversely middle zone of said diaper.  
     
     
         3 . The diaper according to  claim 1 , wherein said first layer is formed with an elastically stretchable film or a nonwoven fabric made of crimped fiber.  
     
     
         4 . The diaper according to  claim 1 , wherein said continuous fibers of said second layer are made of polypropylene or propylene copolymer.  
     
     
         5 . The diaper according to  claim 1 , wherein said first layer is formed with a liquid-impervious sheet and lies inside said second layer.  
     
     
         6 . The diaper according to  claim 1 , wherein said first layer is formed with a liquid-impervious sheet and lies inside said second layer so that said first layer may be used as a liquid-impervious backsheet for said core member.  
     
     
         7 . A process for making a disposable diaper comprising an elastically stretchable covering member adapted to cover diaper wearer s crotch and waist regions and a liquid-absorbent core member sandwiched between a liquid-pervious sheet destined to come in contact with skin of said diaper wearer and said covering member, said process comprising the steps of: 
 bonding an elastically stretchable first layer destined to form said covering member and a second layer formed with a plurality of inelastically stretchable continuous fibers together in a plurality of intermittently formed bonding zones and thereby to form a composite sheet, stretching only a portion of said composite sheet in one direction so that said first layer forming said portion may be elastically stretched together with said continuous fibers, and then leaving said composite sheet contract under a contractile force of said first layer to form said covering member.