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 the length of the mat and corresponding to the machine direction of the manufacturing method;
• a second extension in the y-direction, corresponding to width of the mat, preferably being shorter said first extension and corresponding to the cross-machine direction of the manufacturing method;
• a third extension, z-direction or thickness, perpendicular to said first and said second extensions, and significantly 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 during the intended use;
• a second surface of a second cover web
• opposite said first surface and adapted for being oriented towards a support during the intended use,
• an absorbent core there between,
• exhibiting an absorbent core margin and an x-y-extension smaller than the x-y-extension of said mat, and
• comprising fibrous, preferably cellulosic material, and
• optionally 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,
• said absorbent mat further
• optionally comprising at least a first core wrap material;
• and
• further comprising a perimeter seal
• exhibiting a perimeter seal width extending perpendicular to the perimeter seal line of at least 5 mm, preferably more than 10 mm and less than 40 mm, preferably less than 30 mm;
• and
• being positioned along an essentially closed perimeter seal line—within the x-y-extending margins of the absorbent mat, and
• comprising superabsorbent material,
• at a local BW-concentration of at least 60% of the combined basis weight of fibers, preferably cellulose fibers, SAP, and core carrier, if present,
• 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 preferably cellulose fibers, and/or
• a core web unwinding unit;
• a3) optionally a core wrap supply unit, preferably 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 optionally 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, preferably more than 10 mm and less than 40 mm, preferably less than 30 mm;
• and
• is positioned along an essentially closed perimeter seal line;
• and
• comprising superabsorbent material,
• at a local BW-concentration of at least 60% of the combined basis weight of cellulose, SAP, and core carrier, if present;
• d) enveloping said absorbent core and said perimeter seal between said first and said second cover web;
• e) connecting said 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 cover webs.