Disposable body fluids absorbent article

Abstract: A disposable body fluids bsorbent article is provided on an outer surface of a backsheet thereof with a tape fastener for fastening the used article in a rolled up condition for disposable. The tape fastener longitudinally includes a fixed end portion secured to the outer surface of the backsheet, a free end portion longitudinally opposite to the fixed end portion, an elastically stretchable portion longitudinally extending between these opposite end portions, and an adhesive portion longitudinally extending between the free end portion and the elastically stretchable portion and releasably bonded to the outer surface of the backsheet.

Description: This invention relates generally to disposable body fluids absorbent articles such as disposable diapers, training pants and sanitary napkins and more particularly to such articles provided with means by which the used article is fastened in a rolled up condition thereof for disposal. It is well known to provide disposable body fluids absorbent articles with a tape fastener adapted to fasten the used article in a rolled up condition thereof for hygienic disposal thereof. For example, Japanese Laid-Open Utility Model Application No. Sho58-22908 discloses a disposable diaper of open type in which one end portion of an adhesive tape is fixed to the backsheet and the free end portion extends outward beyond the waist-line edge. The diaper soiled with excretions may be rolled up with the backsheet outside toward the free end portion of the tape and then the diaper thus rolled up may be fastened by the free end portion. In addition, Japanese Laid-Open Utility Model Application No. Hei6-77722 discloses a pull-on disposable diaper in which a tape fastener extending vertically of the diaper is fixed at its one end to an outer surface of the backsheet. This tape fastener is normally folded longitudinally thereof and may be unfolded in its actual use and extend outward beyond the waist-line edge of the waist-opening so that the soiled diaper may be fastened by the tape fastener thus unfolded in a rolled up condition thereof for disposal as in the case of the diaper as disclosed in the Japanese Laid-Open Utility Model Application No. Sho58-22908. EP-A-0623330 discloses a similar pull-on diaper in which an elongate elastic tape fastener is attached to the backsheet of the diaper and is folded in its un-used condition and may be unfolded for use. The tape may be formed of an elastically expansible member. In the case of the diaper disclosed in the Japanese Laid-Open Utility Model Application No. Sho58-22908, the longer the adhesive tape is, the longer the free end portion extends outward beyond the waist line edge, which may obstruct the diaper to be smoothly worn. Accordingly, it is difficult in practice to employ a relatively long adhesive tape. Also in the case of the diaper disclosed in the Japanese Laid-Open Utility Model Application No. Hei6-77722 and EP-A-0 623 330, the longer the adhesive tape is, the more bulky the folded adhesive tape becomes. Consequently, this folded adhesive tape may leap to the baby's eye and the baby may play with this. Once the adhesive tape has been unfolded by the baby, it is not easy to fold this again and in consequence, a troublesome labor is forced upon the mother. The problem common to the well known diapers as have have been mentioned above lies in that, after the diaper soiled with excretions has been removed from the baby and rolled up and tightly fastened by the adhesive tape stretched with a high tension, the adhesive once anchored to the rolled diaper may often be peeled off from the outer surface of the rolled diaper under the tension of the adhesive tape unless the anchoring of the adhesive tape is reliably firm. In view of the problem as has been described above, it is a principal object of the invention to provide a disposable body fluids absorbent article such as a disposable diaper with a relatively short tape fastener allowing such article to be easily held in its rolled up condition without any apprehension that the tape fastener might be peeled off from the outer surface of the rolled article once the tape fastener has been anchored to the outer surface. The object set forth above is achieved, according to the invention, by a disposable body fluids absorbent article comprising a topsheet on a skin-contactable side, a backsheet on a non-skin-contactable side, and a tape fastener adapted to fasten the body fluids absorbent article soiled with excretions in a rolled up condition thereof in a predetermined direction, characterised in that: said tape fastener is unfolded in its un-used condition and comprises: a substantially non-stretchable fixed end portion (22) secured to an outer surface of said backsheet, a substantially non-stretchable free end portion (32) longitudinally opposite to said fixed end portion and adapted to be held by the user's fingers, an elastically stretchable portion (24) longitudinally extending in an unstretched condition from said fixed end portion towards said free end portion and a substantially non-stretchable adhesive portion longitudinally extending between said free end portion and said elastically stretchable portion with an inner surface of said adhesive portion facing the outer surface of said backsheet and releasably bonded to said outer surface. In another aspect of the invention, said elastically stretchable portion comprises an elastically stretchable sheet having an elongation percentage in the longitudinal direction of 100-1500% and an elastic recovery percentage of 10-90% relative to said elongation percentage. In yet another aspect of the invention, after said adhesive portion releasably bonded to the outer surface of said backsheet has been peeled off from the outer surface of said backsheet, said tape fastener can be longitudinally stretched until a portion of said tape fastener at least including said free end portion and said adhesive portion can get beyoud an outer edge of said body fluids absorbent article rolled up and reach a position lying outward beyoud said outer edge. The invention allows the tape fastener used to fasten the disposable body fluids absorbent article to be shortened sufficiently to avoid any apprehension that the tape fastener might obstract the article to be smoothly worn, since the tape fastener has an appropriate stretchability. In addition, the tape fastener is not readily peeled off from the article which has been fastened in a rolled up condition thereof by the stretched tape fastener, since the contractile force of this tape fastener is progressively reduced as a time elapses after the tape fastener has been stretched to fasten the rolled up article. Other and further objects, features and advantages of the invention will appear more fully from the following description. Fig. 1 is a perspective view showing a pull-on disposable diaper type as an embodiment of the invention as partially broken away; Fig. 2 is a sectional view taken along line II-II in Fig. 1, showing an important part of the diaper; and Fig. 3 is a perspective view showing the diaper as rolled up. A pull-on disposable diaper 1 shown by Fig. 1 in a perspective view as partially broken away is a specific embodiment of the inventive body fluids absorbent article. The diaper 1 comprises a liquid-permeable topsheet 2 on a skin-contactable side, a liquid-impermeable backsheet 3 on a non-skin-contactable side and a liquid-absorbent core 4 extending between these two sheets 2, 3. The diaper 1 has a front waist region 5, a rear waist region 7 and a crotch region 8 extending between these two regions 6, 7. The front and rear waist regions 6, 7 put flat and joined together along transversely opposite side edges 11, 12 thereof so as to define a waist-opening 13 and a pair of leg-openings 14. The waist-opening 13 as well as the leg-openings 14 are provided along peripheral edges thereof with elastic members 16 and 17, respectively, each comprising a plurality of elastic elements. The elastic member 16 serves to fit the diaper 1 around the waist of the wearer and the elastic members 17 serve to fit the diaper 1 around the legs of the wearer. These elastic members 16, 17 are secured in elastically stretched conditions thereof to an inner surface of at least one of the topsheet 2 and backsheet 3 at portions of these sheets 2, 3 extending outward beyond a peripheral edge of the absorbent core 4. The rear waist region 7 is provided at a circumferentially middle position with a tape fastener 21 oriented vertically of the diaper 1. Fig. 2 is a sectional view taken along line II-II in Fig. 1, showing a construction of the tape fastener 21. The tape fastener 21 comprises, as viewed in the longitudinal direction (i.e., vertical direction), a lower end member 22, an upper end member 23 and an intermediate member 24 extending between the lower and upper end members 22, 23. The lower end member 22 has its entire inner surface applied with a first adhesive 26 so that the lower end member 22 is bonded to a lower end portion 27 of the intermediate member 24 over a second applied zone 26B of the first adhesive 26 and to an outer surface of the backsheet 3 over a first adhesive zone 26A of the first adhesive 26. Similarly, the upper end member 23 has its inner surface applied with second adhesive 28 so that the upper end member 23 is bonded to an upper end portion 29 of the intermediate member 24 over a third adhesive zone 28A of the second adhesive 28, to the outer surface of the backsheet 3 over a fourth adhesive zone 28B of the second adhesive 28 and to a film member 35 to be held by the user's fingers over a fifth adhesive zone 28C of the second adhesive 28. All these adhesive zones except the fourth adhesive zone 28B (i.e., the first, second, third and fifth adhesive zones 26A, 26B, 28A, 28C) bond the members 22, 23, 24, 35 and the backsheet 3 to those opposed to them, respectively, so firmly that these members and the backsheet practically can not be separated from one another. Over the fourth adhesive zone 28B, on the other hand, the tape fastener 21 is releasably bonded to the backsheet 3. Such condition of releasable bonding may be achieved by applying the outer surface of the backsheet 3 with a mold release agent and/or regulating an adhesive power of the second adhesive 28. The intermediate member 24 has an elastically stretchable portion 31 of a predeterminded length between the lower end member 22 and the upper end member 23. Since the upper portion 32 of said upper end member 23 has its inner surface to which the film member 35 is bonded, the upper end portion 32 may be held by the user's fingers to separate the tape fastener 21 from the backsheet 3 over the fourth adhesive zone 28B. The lower end member 22 and the upper end member 23 forming parts of the tape fastener 21 may be made of sheet-like material such as substantially non-stretchable plastic film or nonwoven fabric. An example of such sheet-like material is polyester film having a thickness of 0.02 - 0.3 mm. The intermediate member 24 may be made of elastically stretchable sheet-like material, preferably, stretchable sheet-like material having an elongation percentage of 100 - 1500 % and a percentage of elastic recovery after such elongation of 10 - 90 %. An example of such sheet-like material is elastomer film having a thickness of 0.02 - 0.3 mm. It should be understood that said percentage of elastic recovery is based on a length measured after a strip of 10 mm X 50 mm cut from the sheet in question is stretched until a desired elongation percentage is reached within 5 seconds and held in this state for one minute, then the stretching force is released and left in this released state for further one minute. Fig. 3 is a perspective view showing the diaper 1 rolled up and fastened by the tape fastener 21. The diaper 1 may be rolled up from the crotch region 8 toward the waist-opening 13 as shown, or from the front waist region 6 toward the rear waist region 7 with the topsheet 2 inside after transversely opposite side edges of the diaper 1 have been cut apart back and forth along their bonded lines. Thereafter the tape fastener 21 may be pulled up with the upper end portion 32 held by the user's fingers (as indicated by imaginary lines in Fig. 1) so as to peel the fourth adhesive zone 28B off from the backsheet 3 and thereby to stretch the stretchable portion 31 of the intermediate member 24 until the upper end of the stretchable portion 31 gets beyond the waist opening, whereupon the tape fastener 21 may be anchored on the outer surface of the backsheet 3. After the diaper 1 has been left in this rolled up condition for a time, a stretch street initially generated in the stretchable portion 31 is relieved and a contractile force in the stretchable portion 31 tending to peel the fourth adhesive zone 28B off from the backsheet 3 is correspondingly relieved. Consequently, the fourth adhesive zone 28B with the lapse of time reduces any apprehension that the fourth adhesive zone 28B might be peeled off from the backsheet 3 under the contractile force of the stretchable portion 31. Bonding of the lower end member 22 and the upper end member 23 to the backsheet 3 is facilitated when the members 22, 23 are non-stretchable and high in their rigidities. These members 22, 23 are preferably formed by the strips provided separately of the intermediate member 24. The position at which the tape fastener 21 is provided on the diaper 1 is not limited to the position as shown with respect to the specific embodiment. A position at which the diaper 1 is provided, a full length of the tape fastener 21, a length of the stretchable portion 31, and upper and/lower limits of the length to which the stretchable portion 31 is stretched may be determined depending on a manner in which the used diaper 1 is to be rolled up. However, it is desired to dimension and construct the tape fastener 21 so that its free end can be stretched to get beyond the outer edge of the rolled up diaper 1. The tape fastener 21 of this invention can be useful not only for the diaper 1 but also for the other body fluids absorbent articles such as training pants, pants for incontinent patient, sanitary napkins, bandages and the like. Having described the invention as related to the embodiment shown in the accompanying drawings, it is our. intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within the scope of the accompanying claims.

Claims: A disposable body fluids absorbent article comprising a topsheet (2) on a skin-contactable side, a backsheet (3) on a non-skin-contactable side, and a tape fastener (21) adapted to fasten the body fluids absorbent article soiled with excretions in a rolled up condition thereof in a predetermined direction, characterised in that : said tape fastener is unfolded in its un-used condition and comprises: a substantially non-stretchable fixed end portion (22) secured to an outer surface of said backsheet, a substantially non-stretchable free end portion (32) longitudinally opposite to said fixed end portion and adapted to be held by the user's fingers, an elastically stretchable portion (24) longitudinally extending in an unstretched condition from said fixed end portion (22) towards said free end portion (32) and a substantially non-stretchable adhesive portion (28) longitudinally extending between said free end portion and said elastically stretchable portion with an inner surface of said adhesive portion facing the outer surface of said backsheet and releasably bonded to said outer surface. The body fluids absorbent article according to claim 1, wherein said elastically stretchable portion (24) comprises an elastically stretchable sheet having an elongation percentage in the longitudinal direction of 100-1500% and an elastic recovery percentage of 10-90% relative to said elongation percentage. The body fluids absorbent article according to claim 1 or claim 2, wherein, after said adhesive portion (28) has been peeled off from the outer surface of said backsheet (3), said tape fastener can be longitudinally stretched until a portion of said fastener at least including said free end portion (32) and said adhesive portion (28) extends beyond an outer edge of said rolled up body fluids absorbent article and reaches a position lying outward beyond said outer edge.

Inventors: INOUE TOSHIO, KAWAMURA KOUJI, KIDO TSUTOMU, SOGA HIRYOUKI, INOUE, TOSHIO, KAWAMURA, KOUJI, KIDO, TSUTOMU
Applicants: UNI CHARM CORP, UNI-CHARM CORPORATION
Application year: 1997
Main classification: A61F13
IPC codes: A61F5, A61F13