Absorbent articles for personal hygiene, such as disposable diapers for infants, training pants for toddlers or adult incontinence undergarments are designed to absorb and contain body exudates, in particular large quantity of urine. These absorbent articles comprise several layers providing different functions, for example a topsheet, a backsheet and in-between an absorbent core, among other layers.
The function of the absorbent core is to absorb and retain the exudates for a prolonged amount of time, for example overnight for a diaper, minimize re-wet to keep the wearer dry and avoid soiling of clothes or bed sheets. The majority of currently marketed absorbent articles comprise as absorbent material a blend of comminuted wood pulp with superabsorbent polymers (SAP) in particulate form, also called absorbent gelling materials (AGM), see for example U.S. Pat. No. 5,151,092 (Buell). Absorbent articles having a core consisting essentially of SAP as absorbent material (so called “airfelt-free” cores) have also been proposed but are less common than traditional mixed cores (see e.g. WO2008/155699 (Hundorf), WO95/11652 (Tanzer), WO2012/052172 (Van Malderen)).
Absorbent articles comprising a core with slits or grooves have also been proposed, typically to increase the fluid acquisition properties of the core WO95/11652 (Tanzer) discloses absorbent articles which include superabsorbent material located in discrete pockets having water-sensitive and water-insensitive containment structure. WO2009/047596 (Wright) discloses an absorbent article with a slit absorbent core.
These absorbent articles may typically comprise leg cuffs which provide improved containment of liquids and other body exudates. Leg cuffs may also be referred to as leg bands, side flaps, barrier cuffs, or elastic cuffs. Usually each leg cuff will comprise one or more elastic string or element comprised in the chassis of the diaper for example between the topsheet and backsheet in the area of the leg openings to provide an effective seal while the diaper is in use. These elasticized elements which are substantially planar with the chassis of the absorbent article will be referred to herein as gasketing cuffs. It is also usual for the leg cuffs to comprise raised elasticized flaps, herein referred to as barrier leg cuffs, which improve the containment of fluid in the leg-torso joint regions. Each barrier leg cuff typically comprises one or more elastic strings. U.S. Pat. No. 4,808,178 and U.S. Pat. No. 4,909,803 (Aziz) describe disposable diapers having such raised elasticized flaps. U.S. Pat. No. 4,695,278 (Lawson) and U.S. Pat. No. 4,795,454 (Dragoo) describe disposable diapers having dual cuffs, including gasketing cuffs and barrier leg cuffs. U.S. Pat. No. 4,704,116 (Enloe) discloses an absorbent garment comprising a pair of gasketing cuffs and a pair of barrier leg cuffs which attached to or formed from the topsheet and spaced inwardly from said elasticized leg openings, defining a waste-containment pocket.
Absorbent articles generally have a high absorbent capacity and the absorbent core can expand to several times its weight and volume. These increases will typically cause the absorbent articles to sag in the crotch region as it becomes saturated with liquid, which may cause the barrier cuffs to partially lose contact with the wearer's skin. This can lead to a loss of functionality of the barrier cuffs, with the increased possibly of leakage.
US2007/088308 (Ehrnsperger) addresses this problem by suggesting a barrier cuff strip which extends longitudinally from front to back waist regions along the topsheet and includes front and back ends and proximal and distal edges connecting the front and back ends. The distal edge is attached at a cuff end bond region having an outer bond edge and an inner bond edge spaced longitudinally from the outer bond edge. A longitudinal distance from the inner bond edge to the laterally extending side at the one of the front and back waist regions is about ½ or more of a longitudinal length of the front or back waist regions.
US2004/220541 (Suzuki) discloses an absorbent sheet having concave and convex portions on its surface and spontaneously exhibiting a three-dimensional structure in that a concave-convex structure is formed. US2007/244455 (Hansson) discloses an absorbent core in an absorbent article provided with at least two folding guides extending in a substantially longitudinal direction in the crotch region and dividing at least a part of the crotch region of the absorbent core in a central portion and two lateral portions as seen in a transverse direction. At least two stretchable crotch elastic members are arranged in the crotch portion of the article and are attached to the absorbent core and/or to the inner or outer cover.
Although the prior art has provided different solutions to the problem of improving leakage prevention, it still beneficial to develop new and improved solution to provide better fit of the leg cuffs at high load. The present inventors have found that it may be beneficial for the free edges of the barrier leg cuffs to follow the fold lines between legs and torso. These fold lines are a very good position for the raised edge of the barrier leg cuffs to follow because of (a) it is a low motion area, and (b) it is in a region closest to the body. These anatomical fold lines are not straight, but rather the distance between the left and right fold line is larger in the front and back than in the crotch.
The inventors have found that when the width of the diaper between the barrier leg cuffs in the crotch portion is reduced as indicated further below, the barrier leg cuff's free edge can better follow the curved fold lines as the article becomes loaded which improves leakage prevention. This is particularly advantageous as the leakage prevention is thus increased when the article becomes highly loaded and thus when the leakage prevention is most needed. The inventors have found that this effect was particularly present when the absorbent core contains high proportions of superabsorbent polymers and at least partially longitudinally extending channels.
USPTO Backgrounds
USPTO Backgrounds