Absorbent core, articles comprising said core, and methods of making

Abstract

An absorbent core comprising substantially continuous zones of one or more high fluid distribution structures and discontinuous zones of fluid absorption structures surrounding the one or more high fluid distribution structures, wherein the one or more high fluid distribution structures are arranged to distribute fluid across the absorbent core at a speed that is faster than the speed of fluid distribution across the absorbent core by said discontinuous fluid absorption structures, and wherein said continuous zones extend along a path that is substantially parallel to at least a portion of the perimeter of the core, said portion of the perimeter of the core comprising at least a portion of the sides of the core and one of the ends of the core.

1 . An absorbent core ( 101 ) comprising:
 a front portion ( 122 );   a back portion ( 124 );   a crotch portion ( 126 ) position between the front portion ( 122 ) and the back portion ( 124 ); and   a longitudinal axis extending along a length of said core ( 101 ) and crossing said front, crotch and back portions ( 122 ,  126 ,  124 ), the absorbent core ( 101 ) having a width extending perpendicular to said length and a perimeter comprising at least two opposing ends ( 102 ,  103 ) and at least two opposing sides ( 104 ,  105 ) positioned between said ends ( 102 ,  103 ) characterized in that the absorbent core ( 101 ) comprises one or more substantially interconnected channels ( 106 ) substantially free of three-dimensional absorbent material extending through the crotch portion ( 126 ) along and substantially parallel to the longitudinal axis and further extending along at least a portion of said width of the core from one side of the core to the other,   wherein at least one of the interconnected channels ( 106 ) forms a shape having a closed end in the form of a U-bend, wherein the closed end is positioned proximal to the back portion ( 124 ) of the absorbent core ( 101 ), and wherein at least one of the interconnected channels ( 106 ) forms a shape having an open end in the form of two diverging ends or a funnel-shape, wherein the open end is positioned proximal to the front portion ( 122 ) of the absorbent core ( 101 ) and distal from said closed end.   
     
     
         2 . An absorbent core ( 101 ) according to  claim 1 , wherein at least one of the interconnecting channels ( 106 ) comprises:
 a first channel portion ( 107 ) extending substantially along the longitudinal axis proximal to a first side ( 104 ) of the core ( 101 );   a second channel portion ( 108 ) extending substantially along the longitudinal axis proximal to a second side ( 105 ) of the core ( 101 ); and   at least one connecting channel portion ( 109 ) in fluid communication with said first and second channel portions ( 107 ,  108 ) and forming said closed end in the form of a U-bend.   
     
     
         3 . An absorbent core ( 101 ) according to  claim 1  wherein each substantially interconnected channel ( 106 ) comprises:
 a first channel portion ( 107 ) extending substantially along the longitudinal axis proximal to a first side ( 104 ) of the core ( 101 ); 
 a second channel portion ( 108 ) extending substantially along the longitudinal axis proximal to a second side ( 105 ) of the core ( 101 ); and 
 at least one connecting channel portion ( 109 ) in fluid communication with said first and second channel portions ( 107 ,  108 ). 
 
     
     
         4 . An absorbent core ( 101 ) according to  claim 2  wherein the connecting channel portion ( 109 ) extends substantially along the width of said core ( 101 ), forming a closed end shape within a surface of said core ( 101 ) along a plane parallel to the longitudinal axis, and positioned opposite to an open end shape formed by non-connected first and second terminal positions ( 110 , 111 ) of the interconnected channel ( 106 ) 7  of the first and second channel portions ( 107 ,  108 ) respectively, said non-connected first and second terminal positions ( 110 ,  111 ) being distal to each other and proximal to the first and second sides ( 104 ,  105 ) of said core ( 101 ) respectively. 
     
     
         5 . An absorbent core ( 101 ) according to  claim 4  wherein the closed end is substantially curvilinear in shape, forming a convex shape between the first and second channel portions ( 107 ,  108 ), or is substantially linear in shape, forming a straight or triangular shape between the first and second channel portions ( 107 ,  108 ). 
     
     
         6 . An absorbent core ( 101 ) according to  claim 1  having a first distance (d 1 ) between the first channel portion ( 107 ) and the second channel portion ( 108 ), a second distance (d 2 ) between the first channel portion ( 107 ) and the second channel portion ( 108 ), wherein the first distance (d 1 ) is proximal to the front portion ( 102 ) of the core ( 101 ) and the second distance (d 2 ) is proximal to the back portion ( 103 ) of the absorbent core ( 101 ), and wherein the first distance (d 1 ) is greater than the second distance (d 2 ). 
     
     
         7 . An absorbent core ( 101 ) according to  claim 1  comprising a first nonwoven web; a second nonwoven web; and a three-dimensional absorbent material positioned between the first and second nonwoven webs to form an absorbent core laminate, wherein the three-dimensional absorbent material comprises a fibrous web comprising airlaid fibers, and comprises a predetermined amount of super absorbent polymer dispersed therethrough. 
     
     
         8 . An absorbent core ( 101 ) according to  claim 1  wherein the substantially interconnected channels ( 106 ) have a regular or irregular depth, said depth being measured on an axis perpendicular to both the longitudinal axis and the axis along the width of the core ( 101 ), wherein the cross-section of said channels ( 106 ) is selected from the group consisting of curved, polygonal and combinations thereof. 
     
     
         9 . An absorbent article ( 10 ,  20 ,  300 ) comprising a core ( 101 ) according to  claim 1 , said article being selected from disposable diapers or diaper pants; disposable incontinence diapers or diaper pants; sanitary napkins; and panty liners; and wherein the channels in said core remain visible both before and after use of the article. 
     
     
         10 . (canceled) 
     
     
         11 . A method of tri-stage fluid distribution in an absorbent article containing a core having substantially interconnected channels, the method comprising: distributing a first fluid at a first speed, distributing a second fluid at a second speed and distributing a third fluid at a third speed, said first speed being greater or equal to said second speed and said third speed being less than said first speed and less than or equal to said second speed, wherein the first fluid distribution is driven by the substantially interconnected channels, the second fluid distribution is driven by a three-dimensional absorbent material comprised within the core, and the third fluid distribution is driven by an amount of super absorbent polymer dispersed within the three-dimensional absorbent material. 
     
     
         12 . A process of making an absorbent core ( 101 ) according to  claim 1  comprising the steps of:
 i. providing a mold and comprising a 3D insert therein, said 3D insert being an inverse shape of one or more substantially interconnected channels, wherein substantially the entire surface of the mold is in fluid communication with an under-pressure source except for the 3D insert; 
 ii. applying a first nonwoven web to said mold; 
 iii. applying a three-dimensional absorbent material over at least a portion of said nonwoven; 
 iv. applying a second nonwoven web directly or indirectly over the three-dimensional absorbent material; 
 v. optionally applying a bonding step to form a laminate comprising said first nonwoven, said second nonwoven and said three-dimensional absorbent material therebetween; 
 vi. optionally removing said laminate from the mold to form an absorbent core comprising one or more substantially interconnected channels having an inverse shape of said 3D insert; and 
 wherein at least for the duration of step iii the underpressure source is arranged to provide a vacuum force forcing said three-dimensional absorbent material around the 3D insert such to substantially evacuate the surface thereof from three-dimensional absorbent material and form one or more substantially interconnected channels substantially free of three-dimensional absorbent material. 
 
     
     
         13 . A process according to  claim 12  wherein the bonding step comprises applying an adhesive on a surface of the second nonwoven web and joining said web to said first nonwoven web and/or three-dimensional absorbent material, the adhesive being applied in continuous or discontinuous spaced apart stripes aligned with said channels such that the resulting core laminate comprises adhesive rich and adhesive poor regions, wherein the adhesive rich regions are substantially located along said channels and the adhesive poor regions are located in areas of the core other than said channels. 
     
     
         14 . A process according to  claim 12  wherein the channels substantially free of absorbent material are formed only by action of said vacuum force and no additional embossing or mating of one or more mating parts or mating strips. 
     
     
         15 . An absorbent core ( 101 ) according to  claim 2 , wherein the first and second channel portions ( 107 ,  108 ) diverge away from the longitudinal axis at least along a portion of the interconnecting channel ( 106 ) exiting from the U-bend, thereby at least partially forming a funnel-shaped interconnected channel near the closed end. 
     
     
         16 . An absorbent core ( 101 ) according to  claim 4 , wherein said terminal positions ( 110 ,  111 ) face away from each other such to form a funnel-shaped gap therebetween. 
     
     
         17 . An absorbent core ( 101 ) according to  claim 6 , wherein the first distance (d 1 ) is at least 1.5d 2 . 
     
     
         18 . An absorbent core ( 101 ) according to  claim 6 , wherein the first distance (d 1 ) is from 1.8d 2  to 3d 2 . 
     
     
         19 . An absorbent core ( 101 ) according to  claim 7 , wherein the first nonwoven web is in the form of a backsheet and the second nonwoven web is in the form of a topsheet. 
     
     
         20 . An absorbent article ( 10 ,  20 ,  300 ) comprising a core ( 101 ) according to  claim 9 , wherein the channels are more visible after use than before use of the article.