Method for production of disposable absorbent articles

Abstract

A method for production of disposable pant diapers, the method including providing a length of a substantially homogeneous elastic laminate web having a maximum elastic extensibility in a first direction of at least 40% under a peak load F p ; advancing the length of the substantially homogeneous elastic laminate web in the first direction; attaching individual absorbent cores to the length of the elastic laminate web during the advancing to create a strip, while maintaining the length of the substantially homogeneous elastic laminate web under a tensioning load F t in the first direction; folding the strip onto itself; maintaining the length of the substantially homogeneous elastic laminate web under the tensioning load F t in the first direction during the folding; the tensioning load F t satisfying the condition: 0.03 F p ≦F t ≦0.25 F p ; and welding the substantially homogeneous elastic laminate web and severing the individual pant diapers along the weld lines.

What is claimed is: 
     
         1 . A method for production of disposable pant diapers, the method comprising:
 providing a continuous length of a substantially homogeneous elastic laminate web having a maximum elastic extensibility in a first direction of at least 40% under a peak load F p ;   advancing said continuous length of said substantially homogeneous elastic laminate web in said first direction;   attaching individual absorbent cores to said continuous length of said elastic laminate web at spaced intervals during said advancing to create a strip comprising said continuous length of said substantially homogeneous elastic laminate web loaded with a plurality of said cores, while maintaining said continuous length of said substantially homogeneous elastic laminate web under a tensioning load F t  in said first direction;   folding said strip onto itself to form a fold edge and an open edge of the pant diapers;   maintaining said continuous length of said substantially homogeneous elastic laminate web under the tensioning load F t  in said first direction during said folding;   said tensioning load F t  satisfying the condition: 0.03 F p ≦F t ≦0.25 F p ; and   welding said substantially homogeneous elastic laminate web to define weld lines intermittently transverse to the first direction and severing the individual pant diapers along the weld lines.   
     
     
         2 . The method as claimed in  claim 1 , whereby said tensioning load F t  satisfies the condition: 0.05 F p ≦F t ≦0.25 F p . 
     
     
         3 . The method as claimed in  claim 1 , whereby said tensioning load F t  satisfies the condition: 0.03 F p ≦F t ≦0.20 F p . 
     
     
         4 . The method as claimed in  claim 1 , whereby said tensioning load F t  satisfies the condition: 0.05 F p ≦F t ≦0.20 F p . 
     
     
         5 . The method as claimed in  claim 1 , wherein said substantially homogeneous elastic laminate web includes a first nonwoven layer affixed to a first surface of a film layer. 
     
     
         6 . The method as claimed in  claim 5 , wherein said substantially homogeneous elastic laminate web further comprises a second nonwoven layer affixed to a second surface of said film layer. 
     
     
         7 . The method as claimed in  claim 5 , wherein said film layer is an apertured three-layer PE/styrene-based film/PE elastomeric film. 
     
     
         8 . The method as claimed in  claim 1 , wherein said substantially homogenous elastic laminate web exhibits a non-linear load-strain curve relationship which relationship includes a knee point within the range of 0.03 F p ≦F t ≦0.20 F p . 
     
     
         9 . The method as claimed in  claim 8 , wherein the knee point is located at a position where a load/strain gradient increases sharply. 
     
     
         10 . The method as claimed in  claim 5 , wherein said first nonwoven layer is affixed to the first surface of the film layer with glue. 
     
     
         11 . The method as claimed in  claim 7 , wherein said PE is low crystallinity polyethylene or metallocene-catalyzed low crystallinity polyethylene, and/or the styrene-based film is formed of butadiene-styrene copolymers, styrene block polymers and blends thereof. 
     
     
         12 . The method as claimed in  claim 6 , wherein said first or said second nonwoven layer comprises a spunbond or carded material selected from the group consisting of: polypropylene, polyethylene, polyester and other polyolefin homopolymers and copolymers. 
     
     
         13 . The method as claimed in  claim 1 , wherein said substantially homogeneous elastic laminate web constitutes an outer cover of said pant diaper. 
     
     
         14 . The method as claimed in  claim 5 , wherein said film layer has a basis weight from about 20 to about 40 g/m 2 . 
     
     
         15 . The method as claimed in  claim 6 , wherein each of said first and said second nonwoven layers has a basis weight of from about 10 g/m 2  to about 40 g/m 2 . 
     
     
         16 . The method as claimed in  claim 6 , wherein said first or said second nonwoven layer has a basis weight of from about 12 g/m 2  to about 30 g/m 2 . 
     
     
         17 . The method as claimed in  claim 6 , wherein said first or said second nonwoven layer has a basis weight of from about 15 g/m 2  to about 25 g/m 2 . 
     
     
         18 . The method as claimed in  claim 16 , wherein each of said first and said second nonwoven layers has a basis weight of from about 12 g/m 2  to about 30 g/m 2 . 
     
     
         19 . The method as claimed in  claim 17 , wherein each of said first and said second nonwoven layers has a basis weight of from about 15 g/m 2  to about 25 g/m 2 . 
     
     
         20 . The method as claimed in  claim 11 , wherein said styrene block polymers comprise styrene/isoprene/styrene (SIS), styrene/butadiene/styrene (SBS), or styrene/ethylene-butadiene/styrene (SEBS) block copolymer. 
     
     
         21 . The method as claimed in  claim 5 , wherein said film layer has a basis weight from about 20 g/m 2  to about 100 g/m 2 . 
     
     
         22 . The method as claimed in  claim 1 , wherein said substantially homogenous elastic laminate web includes two layers having respective levels of elasticity different from one another. 
     
     
         23 . The method as claimed in  claim 22 , wherein both of said two layers comprise fibers. 
     
     
         24 . The method as claimed in  claim 1 , wherein said substantially homogenous elastic laminate web exhibits a non-linear load-strain curve relationship. 
     
     
         25 . A method for production of disposable pant diapers, the method comprising:
 providing a continuous length of a substantially homogeneous elastic laminate web having a maximum elastic extensibility in a first direction of at least 40% under a peak load F p ;   advancing said continuous length of said substantially homogeneous elastic laminate web in said first direction and attaching individual absorbent cores to said continuous length of said substantially homogeneous elastic laminate web at spaced intervals, while maintaining said continuous length of said substantially homogeneous elastic laminate web under a tensioning load F t  in said first direction during said advancing;   folding said substantially homogeneous elastic laminate web with the individual absorbent cores attached thereto onto itself to form a fold edge and an open edge of the pant diapers;   maintaining said continuous length of said substantially homogeneous elastic laminate web under the tensioning load F t  in said first direction during said folding,   said tensioning load F t  satisfying the condition: 0.03 F p ≦F t ≦0.25 F p , and   welding said substantially homogeneous elastic laminate web to define weld lines intermittently transverse to the first direction and severing the individual pant diapers along the weld lines.   
     
     
         26 . The method as claimed in  claim 25 , whereby said tensioning load F t  satisfies the condition: 0.05 F p ≦F t ≦0.25 F p . 
     
     
         27 . The method as claimed in  claim 25 , wherein said substantially homogeneous elastic laminate web includes a first nonwoven layer affixed to a first surface of a film layer. 
     
     
         28 . The method as claimed in  claim 27 , wherein said substantially homogeneous elastic laminate web further comprises a second nonwoven layer affixed to a second surface of said film layer. 
     
     
         29 . The method as claimed in  claim 27 , wherein said film layer is an apertured three-layer PE/styrene-based film/PE elastomeric film. 
     
     
         30 . The method as claimed in  claim 25 , wherein the substantially homogenous elastic laminate webs each includes two layers having respective levels of elasticity different from one another. 
     
     
         31 . The method as claimed in  claim 25 , wherein said substantially homogenous elastic laminate web exhibits a non-linear load-strain curve relationship. 
     
     
         32 . A method for production of disposable hygienic absorbent articles, the method comprising:
 advancing, in a first direction, first and second continuous lengths of a substantially homogeneous elastic laminate web having a maximum elastic extensibility in the first direction of at least 40% under a peak load F p ;   said first and second continuous lengths being spaced apart in a second direction orthogonal to the first direction;   maintaining said first and second continuous lengths of the substantially homogeneous elastic laminate web under a tensioning load F t  in the first direction during the advancing, the tensioning load F t  satisfying the condition: 0.03 F p ≦F t ≦0.25 F p ;   joining the spaced apart first and second continuous lengths to a non-elastic nonwoven material to thereby define the outer cover of a diaper in which the first and second continuous lengths are respectively located in the front and rear of the diaper, and in which the non-elastic nonwoven material is located in the crotch of the diaper.   
     
     
         33 . The method as claimed in  claim 32 , wherein said non-elastic nonwoven material is a strip of non-elastic nonwoven material. 
     
     
         34 . The method as claimed in  claim 32 , wherein:
 said substantially homogenous elastic laminate webs each includes two layers having respective levels of elasticity different from one another, and   each of said substantially homogenous elastic laminate webs exhibits a non-linear load-strain curve relationship.   
     
     
         35 . The method as claimed in  claim 32 , further comprising the step of attaching individual absorbent cores to said non-elastic nonwoven material. 
     
     
         36 . The method as claimed in  claim 32 , further comprising:
 folding one of the first and second continuous lengths of substantially homogeneous elastic laminate web onto the other of the first and second continuous lengths of substantially homogeneous elastic laminate web to form a fold edge and an open edge of the disposable hygienic absorbent articles;   welding said substantially homogeneous elastic laminate webs together to define weld lines intermittently transverse to the first direction; and   severing the substantially homogeneous elastic laminate webs along the weld lines to form individual disposable hygienic absorbent articles.   
     
     
         37 . The method as claimed in  claim 36 , further comprising:
 folding one of the first and second continuous lengths of substantially homogeneous elastic laminate web onto the other of the first and second continuous lengths of substantially homogeneous elastic laminate web to form a fold edge and an open edge of the disposable hygienic absorbent articles;   welding said substantially homogeneous elastic laminate webs together to define weld lines intermittently transverse to the first direction; and   severing the substantially homogeneous elastic laminate webs along the weld lines to form individual disposable hygienic absorbent articles.