Absorbent mat with perimeter seal

A method for the manufacture of an absorbent mat said absorbent mat exhibiting in Cartesian coordinates

• a first extension in the x-direction, corresponding to a length of the mat and corresponding to a machine direction of the manufacturing method;
• a second extension in the y-direction, corresponding to a width of the mat, the second extension being shorter said first extension and corresponding to a cross-machine direction of the manufacturing method;
• a third extension, z-direction or thickness, perpendicular to said first and said second extensions, and smaller than said first and said second extension;
• said absorbent mat comprising z-directionally a first surface of a first cover web adapted for being oriented towards a user;
• a second surface of a second cover web opposite said first surface and adapted for being oriented towards a support,
• an absorbent core between the first and second surface, exhibiting an absorbent core margin and an x-y-extension smaller than the x-y-extension of said mat, and comprising fibrous material, and a superabsorbent polymer (SAP),
• said first and said second cover web extending longitudinally and laterally outwardly of said absorbent core, thereby forming a mat perimeter circumscribing said core x- and y-directionally, and being connected to each other in said perimeter at a perimeter connection,
• said absorbent mat further optionally comprising at least a first core wrap material;
• and
• further comprising a perimeter seal, said perimeter seal being positioned inwardly from said perimeter connection and exhibiting a perimeter seal width extending perpendicular to the perimeter seal line of at least 5 mm;
• and being positioned along a closed perimeter seal line within the x-y-extending margins of the absorbent mat,
• and said perimeter seal comprising a superabsorbent material, at a local basis weight concentration of at least 60% of a combined basis weight of fibers, the fibers comprising cellulose fibers, SAP, and a core carrier web material, and wherein said SAP is applied at a local basis weight being a ratio of at least 1.05 times, preferably more than 1.10 times as high as a basis weight of the SAP in said absorbent core, said method comprising the steps of
• a) providing
• a1) a first and a second cover web material from a web supply unit, respectively;
• a2) an absorbent core making unit, selected from a fiber lay-down unit for individualizing fibers and forming a web of fibers, wherein said fibers are cellulose fibers, and/or a core web unwinding unit;
• a3) a core wrap supply unit, or a tissue unwind unit;
• a4) at least one superabsorbent material supply and application unit;
• a5) at least one connecting unit;
• b) making an absorbent core with said core making unit and a SAP supply and application unit;
• c) forming a perimeter seal before, during, or after making of the absorbent core such that said perimeter seal is exhibiting a perimeter seal width extending perpendicular to the perimeter seal line of at least 5 mm;
• and is positioned along a closed perimeter seal line;
• and comprising superabsorbent material, at a local basis weight concentration of at least 60% of the combined basis weight of cellulose, SAP, and core carrier, if present, and at a local basis weight that is at least 1.05;
• d) enveloping said absorbent core and said perimeter seal between said first and said second cover web;
• e) connecting said first and second cover webs at least in said mat perimeter outwardly of said perimeter seal, and optionally said core wrap materials to said absorbent core;
• and optionally said core wrap material(s) to said first and second cover webs.