Smart absorbent article, components, and process of making

Abstract

A substrate suitable for incorporation into an absorbent article for automatic detection of wetness events therein, the substrate comprising a first surface capable of being arranged proximal to a body facing side of the absorbent article and a second surface opposite said first surface and capable of being arranged proximal to a garment facing side of said absorbent article, said substrate comprising a plurality of sensor tracks disposed on said first surface and said sensor tracks comprising: at least one central track extending parallel to a length of the substrate and parallel to a longitudinal axis crossing a first end and a second end of the substrate; at least two side tracks extending parallel to the central track and oppositely arranged such that the central track extends therebetween; and wetness sensing tracks extending outboard of said two side tracks, wherein said central track, said side tracks, and said wetness sensing tracks are in electrical communication via one or more shortening elements positioned proximal to said second end and distal from said first end, and wherein the substrate is connectable to a clip-on data processing module at a position proximal to said first end and distal from said shortening elements such to form a closed electrical circuit, typically for measuring resistance and/or capacitance therethrough. In an embodiment said substrate consists of a liquid impermeable backsheet, preferably a breathable liquid impermeable backsheet.

1 . A substrate ( 1 ) suitable for incorporation into an absorbent article ( 100 ) for automatic detection of wetness events therein and/or risk of exudate leakage therefrom, the substrate comprising a first surface ( 2 ) capable of being arranged proximal to a body facing side of the absorbent article ( 100 ) and a second surface ( 3 ) opposite said first surface ( 2 ) and capable of being arranged proximal to a garment facing side of said absorbent article ( 100 ), said substrate ( 1 ) comprising a plurality of sensor tracks ( 101 ) disposed on said first surface ( 2 ) and said sensor tracks ( 101 ) comprising:
 at least one feedback track ( 4 ) extending along a length L of the substrate; and   one or more exudate sensing tracks ( 9 ) in electrical communication with said feedback track ( 4 ),   
       wherein said feedback track ( 4 ) and exudate sensing tracks ( 9 ) are connected in series and wherein the substrate ( 1 ) is connectable to a clip-on data processing module ( 103 ) at a position proximal to a first end ( 5 ) of the substrate ( 1 ) such to form a closed electrical circuit. 
     
     
         2 . A substrate ( 1 ) according to  claim 1  further comprising at least one side tracks ( 7 , 8 ), wherein said feedback track ( 4 ), said side tracks ( 7 , 8 ), and said exudate sensing tracks ( 9 ) are in electrical communication via one or more shortening elements ( 10 ) positioned proximal to said second end ( 6 ) and distal from said first end ( 5 ). 
     
     
         3 . A substrate ( 1 ) according to  claim 1  wherein the sensor tracks ( 101 ) comprise an electrically conductive material, and are printed sensor tracks. 
     
     
         4 . A substrate ( 1 ) according to  claim 3  wherein the printed sensor tracks ( 101 ) comprise a carbon-based ink and/or a conductive polymer-based ink, wherein the carbon-based ink comprises a conductive compound selected from the group consisting of graphene, graphite, nano-carbon-tubes and mixtures thereof, and wherein the conductive polymer-based ink comprises a conductive compound selected from the group consisting of polyacetylene, polypyrrole, polyaniline and copolymers thereof. 
     
     
         5 . A substrate ( 1 ) according to  claim 2  further comprising an insulating layer ( 200 ) adhered thereto and sized to cover the at least one feedback track ( 4 ), said insulating layer ( 200 ) adapted to provide a seal and/or barrier to liquid from coming into contact with said feedback track ( 4 ). 
     
     
         6 . A substrate according to  claim 5  wherein the insulating layer ( 200 ) comprises the one or more shortening elements ( 10 ), such that the feedback track ( 4 ), the side tracks ( 7 , 8 ), and the exudate sensing tracks ( 9 ) are in electrical communication via said shortening elements ( 10 ) when said insulating layer ( 200 ) is joined to the substrate ( 1 ). 
     
     
         7 . A substrate according to  claim 1  comprising at least two feedback tracks ( 4 ) extending parallel to each other, and further being in electrical communication with each other via one or more secondary shortening elements ( 11 ), said secondary shortening elements ( 11 ) being located distal from the shortening elements ( 10 ) and between said shortening elements ( 10 ) and the first end ( 5 ) of the substrate ( 1 ). 
     
     
         8 . A substrate according to  claim 5  wherein at least a substantial portion of the exudate sensing tracks ( 9 ) remains exposed to liquids and are not covered by the insulating layer ( 200 ). 
     
     
         9 . A substrate according to  claim 1  wherein the exudate sensing tracks ( 9 ) are in the form of a repeating grid and/or pattern along the length L of the substrate ( 1 ) and a dimension substantially perpendicular thereto, said grid and/or pattern comprising a plurality of at least partially interconnected resistive members ( 301 ,  302 ,  303 ,  304 ,  305 ,  306 ) each having a shape selected from straight lines; curved lines;
 wave-like; geometrically shaped squares; parallelograms; parallelepipeds; triangles; circles; ellipses; dots; decorative elements; flowers; butterflies and combinations thereof. 
 
     
     
         10 . A substrate according to  claims 2  wherein at least one of the side tracks ( 7 , 8 ) is discontinuous along an axis parallel to the length L of the substrate ( 1 ) such to force a current through the exudate sensing tracks ( 9 ) towards regions proximal to lateral edges ( 12 , 13 ) of the substrate ( 1 ) said lateral edges ( 12 , 13 ) extending between the first and second ends ( 5 , 6 ) and along the length L of the substrate ( 1 ), wherein at least a portion of the exudate sensing tracks ( 9 ) are further alternatingly directly connected and disconnected to the respective side tracks ( 7 , 8 ) along the length L of the substrate ( 1 ). 
     
     
         11 . A substrate according to  claim 1  wherein the exudate sensing tracks ( 9 ) cover a greater surface area of the substrate ( 1 ) than the feedback track ( 4 ), and wherein said exudate sensing tracks ( 9 ) extend both in a direction substantially parallel to the length L and a direction substantially perpendicular thereto. 
     
     
         12 . An absorbent article ( 100 ) suitable for detecting a wetness event therein and/or risk of exudate leakage therefrom, said absorbent article comprising:
 a liquid impermeable backsheet;   a liquid permeable topsheet; and   an absorbent core interposed between said backsheet and topsheet,   
       wherein said backsheet comprises the substrate ( 1 ) according to  claim 1 . 
     
     
         13 . An absorbent article according to  claim 12  further comprising a removable clip-on data processing module ( 103 ) adapted to monitor and process resistance and/or capacitance data acquired from the exudate sensing tracks ( 9 ), said clip-on data processing module ( 103 ) being connectable to the at least one feedback track ( 4 ) and a portion of the exudate sensing tracks ( 9 ) via a slit and/or pocket on the backsheet enabling an electrically conductive portion of said module ( 103 ) to directly come in electrical communication with said at least one feedback track ( 4 ) and said portion of the exudate sensing tracks ( 9 ). 
     
     
         14 . An absorbent article according to  claim 12  wherein the substrate ( 1 ) is positioned such that the first surface ( 2 ) faces the absorbent core, and wherein the insulating layer ( 200 ) is joined to said substrate ( 1 ) such that a liquid impermeable seal is formed providing a barrier to exudates expelled by a subject, when wearing the absorbent article, from coming into direct contact with the at least one feedback track ( 4 ). 
     
     
         15 . A process of making an absorbent article according to  claim 12  comprising the steps of:
 providing a liquid impermeable backsheet and applying a plurality of sensor tracks, to a first surface of the liquid impermeable backsheet; 
 providing an insulating layer ( 200 ) having a width (w), taken along an axis perpendicular to the longitudinal axis (y-y), being less than a width (W) of said backsheet, and optionally applying one or more shortening elements ( 10 ) thereto, optionally further applying one or more secondary shortening elements ( 11 ) thereto; 
 adhering said insulating layer ( 200 ) to said backsheet, said insulating layer being sized and positioned to cover the at least one feedback track ( 4 ), to provide a laminated substrate; 
 providing an absorbent core comprising absorbent material; 
 providing a liquid permeable topsheet; and 
 sandwiching the absorbent core between said laminated substrate and said topsheet. 
 
     
     
         16 . A process according to  claim 15  wherein the sensor tracks are in the form of an electrically conductive ink and the application step comprises the printing of the sensor tracks onto the backsheet, wherein the shortening elements ( 10 ) and the secondary shortening elements ( 11 ) are in the form of an electrically conductive ink and the application step comprises the printing of the secondary shortening elements ( 11 ) onto the insulating layer ( 200 ) or backsheet. 
     
     
         17 . A substrate ( 1 ) according to  claim 4  wherein the conductive polymer-based ink comprises a conductive compound selected from the group consisting of poly(pyrrole)s (PPY), polyanilines (PANT), poly(thiophene)s (PT), poly(p-phenylene sulfide) (PPS), poly(p-phenylene) (PPP), Poly(acetylene)s (PAC), Poly(p-phenylene vinylene) (PPV), poly(3,4-ethylenedioxythiophene) (PEDOT), and mixtures thereof. 
     
     
         18 . The substrate ( 1 ) according to  claim 4  wherein the conductive polymer-based ink comprises poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). 
     
     
         19 . The substrate ( 1 ) according to  claim 5  wherein the exudate sensing tracks ( 9 ) remain exposed and are not covered by said insulating layer ( 200 ). 
     
     
         20 . The absorbent article ( 100 ) according to  claim 12 , wherein the absorbent article ( 100 ) is a disposable diaper or pant.