Satoru Sakaguchi, Kanonji, Japan; and Kana Sawa, Kanonji, Japan.
Assigned to Unicharm Corporation, Ehime, Japan.

Filed: 2/4/13
Issued: 3/14/17

An open-type disposable diaper comprising: a backsheet; a front waistline region; a back waistline region; a crotch region positioned between the front waistline region and the back waistline region; a pair of leg hole openings; an absorber spanning the crotch region and extending to the front waistline region and back waistline region, the absorber including an absorber core; a product longitudinal direction from the front waistline region towards the back waistline region; a product widthwise direction perpendicular to the product longitudinal direction; a crotch stretch unit arranged in the crotch region between the absorber and the backsheet and being stretchable in the product longitudinal direction; a pair of leg stretch units formed along the leg hole openings and being stretchable in at least the product longitudinal direction; and a waist stretch unit formed in the back waistline region and being stretchable in the product widthwise direction; wherein, in a plan view of the open-type disposable diaper, the absorber has an absorber core arrangement region where the absorber core is arranged, the absorber core arrangement region is enclosed by the crotch stretch unit, the leg stretch units, and the waist stretch unit, and is not stretchable, a length of the absorber core arrangement region in the product longitudinal direction is longer than a half of a length of the crotch stretch unit in the product longitudinal direction, the absorber includes, in the back waistline region, a first low rigidity region where a basis weight is lower than a remaining region of the absorber or where the absorber core is not arranged, the waist stretch unit has a region overlapping the first low rigidity region, a dimension of the first low rigidity region in the product widthwise direction gradually increases away from the crotch stretch unit in the product longitudinal direction, the absorber further includes, in the crotch region, a second low rigidity region and a third low rigidity region, the crotch stretch unit has opposing ends in the product longitudinal direction, and the second and third low rigidity regions extend in the product widthwise direction along the opposing ends of the crotch stretch unit.