NZ276514A - Disposable diaper with elasticised cuffs - elastic accommodated in pockets formed by folded longitudinal edges of the facing sheet - Google Patents

Description

New Zealand No. 276514 International No. PCT/SE94/01065 Priority Date(s): \\\}.A3.5....- Complete Specification Filed: .JAfcJ,.\.\|.3Hr Class: (6) P.O. Journal No: NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Disposable absorbent article Name, address and nationality of applicant(s) as in international application form: MOLNLYCKE AB, of S-405 03 Goteborg, Sweden (a SuJtdfcn CO(Y\pUnVJ WO 95/13771 PCT/SE94/01065 2765 1 A TITLE: Disposable absorbent article TECHNICAL FIELD: The present invention relates to a disposable absorbent article such as a disposable diaper according to the preamble of claim 1.

BACKGROUND OF THE INVENTION: Disposable absorbent articles are commonplace and have many uses. As examples of such articles can be named disposable diapers, bandages and sanitary napkins. The purpose of 15 these articles is to absorb and retain discharged liquids, thereby preventing such liquids from soiling for example the clothing of the wearer of such articles.

In order to promote the retention c>f liquids in diapers, it 20 is known from, for example, US-A-4 486 192 to provide an elastic member in the diaper. The elastic member is positioned so that when the diaper is worn, the elastic causes the diaper to form a seal around the legs of the wearer. In said document, the elastic member is sandwiched 25 between a liquid permeable facing sheet and a liquid impermeable backing sheet along opposed longitudinal free edges of the diaper. The elastic member thus occupies a "tunnel" and is adhered to the sheets at regions in which gathering of the diaper is desired. This implies that at 30 non-adhered regions thero is a risk that liquid absorbed by the diaper may escape to the exterior through the tunnel between the permeable and impermeable sheets.

This problem is addressed in US-A-4 850 989 in which 35 longitudinal elastic members are adhesively bonded under tension onto the outside surface of the backing sheet, thereby overcoming the need for a tunnel between the facing 2 sheet and the backing sheet. A disadvantage with this arrangement is that each longitudinal edge face of the diaper consists of the edge face of the facing sheet and the edge face of the backing sheet. This implies that the 5 longitudinal edge faces of the diaper are not particularly smooth, which can lead to irritation of the skin of the wearer.

In US-A-4 808 178, a smooth longitudinal edge is obtained 10 by enclosing the elastic member in a flap which is an extension of the backing sheet. It is stated in said patent that the backing sheet is impervious to liquids and is preferably manufactured from a thin plastic film. Whilst the construction according to US-A-4 808 178 provides a 15 smooth longitudinal edge, the fact that the flap material is impervious to liquids implies that the wearer can experience discomfort due to a build up of perspiration in the area at which the flap contacts the wearer's skin.

SUMMARY OF THE INVENTION: It is therefore an object of the present invention to provide an absorbent article such as a disposable diaper which overcomes the disadvantages mentioned above and which provides increased comfort for the wearer.

This object is achieved in accordance with the present invention by a disposable diaper according to claim 1.

Preferred embodiments of the present invention are detailed 30 in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS: The invention will be described in greater detail in the following by way of example only and with reference to the 35 attached drawings, in which: Fig.l is a plan view of an absorbent article in accordance with the present invention having elasticized leg cuffs, the article being illustrated during a stage of the manufacturing process; Fig. 2 is a partial sectional perspective view taken substantially, along the line II-II of Fig. 1, though with the article in a finished condition.

Fig. 3 is a sectional view along the same line as in Fig. 2, though showing one embodiment according to the invention of the edge portion of the absorbent article; Fig. 4 is a sectional view corresponding essentially to that of Fig. 3, though illustrating a second embodiment of the edge portion of the absorbent article according to the invention; Fig. 5 is a sectional view corresponding essentially to that of Fig. 3, though illustrating a third embodiment of the edge portion of the absorbent article according to the invention, and Fig. 6 is a sectional view corresponding essentially to that of Fig. 3, though illustrating a fourth embodiment of the edge portion of the absorbent article according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS: In the drawings, an absorbent article in the form of a disposable diaper is generally denoted by reference numeral 10. For reasons of clarity, the diaper 10 is shown in Fig. 35 l in a stage occupied by the diaper during its manufacture.

Accordingly, reference numeral 12 denotes joining lines, 4 for example glue lines or heat bonding lines, about which the diaper is gathered in a manner known per se to form a pair of inner cuffs 14 (Fig. 2) through which an elastic chord 16 runs. Due to the gathering of the diaper about the 5 joining lines 12, the diaper adopts a generally hour glass shape with a narrow centrally disposed crotch portion 18 and wider waist portions 20, 22 at transverse end regions of the crotch portion.

In accordance with the invention, the diaper 10 is provided with prestretched elastic means 24 disposed along edge portions, preferably longitudinal edge portions 25, of the diaper. Advantageously, the waist portions 20, 22 may be provided with transversely extending elastic means 26, 28 15 respectively.

To permit the diaper to be fastened around a wearer, fastening means are provided at the waist portions. As illustrated in Fig. l, the waist portion 20 which would 20 normally be disposed at the front of the wearer may be provided with a pair of fastening means such as hook members 30, with each hook member 30 extending from the longitudinal edge portion 25 of the diaper. The fastening means may further comprise a belt 32 extending from the 25 waist portion 22 which, during use, is normally disposed at the back of the wearer. As illustrated in Fig. 1, the belt may be in two halves, with each half extending from the opposed longitudinal edge portions 25 of the diaper. Preferably, the belt is made from a nonwoven material which 30 acts as a loop fastener for the hook members 30.

The structure of the diaper of Fig. 1 will be more easily understood from the partial sectional view through the crotch portion 18, as illustrated in Fig. 2. The diaper 10 35 has a generally hour glass shape and includes a facing sheet 34, a backing sheet 36 and an absorbent core 38 WO 95/13771 PCT/SE94/01065 sandwiched between the facing and backing sheets 34, 36 respectively. The specific components used to form the illustrated diaper may be any of the types commonly used for such purposes. For example, the facing sheet 34 may be 5 any soft flexible liquid permeable material such as a nonwoven fibrous web having a basis weight of around 20 g/mJ. The backing sheet 36 is made from a liquid impermeable material, such as a thin (for example 20n) plastic film of polyethylene, polypropylene, 10 polyvinylchloride or the like. The absorbent core 38 may comprise wood pulp fibres, air-laid tissue, various Fuperabsorbent materials, etc.

As mentioned above with reference to Fig. 1, prestretched 15 elastic means 24 are disposed along the longitudinal edge portions 25 of the diaper. As clearly shown in Fig. 2, the elastic means 2i4 may be in the form of ah elongate elastic band. Advantageously, the elastic band is relatively wide, for example between about 1 and 2 cm, preferably about 1.5 20 cm, so as to reduce the tendency for the leg cuff to mark the wearer.

The arrangement of the elastic means 24 along the longitudinal edge portions 25 of the diaper will now be 25 described with particular reference to Figs. 3 to 6. In accordance with the present invention, the elastic means 24 is surrounded by a pocket of nonwoven material, i.e. a nonwoven fibrous web, advantageously along each of the longitudinal edge portions 25 of the diaper. In the 30 embodiments illustrated in Figs. 3, 4 and 5, the pocket is formed by the facing sheet 34. More particularly, in Figs. 3 and 5 the facing sheet 34 presents a longitudinal free edge portion 40 which is folded under and adhered to the underside of the facing sheet to thereby form a pocket 35 within which the elastic means 24 is accommodated, whilst in Fig. 4 the longitudinal free edge portion 40 of the facing sheet 34 is folded under and adhered to the backing sheet 36. The pocket advantageously extends along the entire longitudinal edge portion 25 of the diaper and the elastic band 24 is adhered to the material forming the 5 pocket at those regions along the longitudinal edge portion at which gathering of the facing sheet is desired, for example in the crotch portion 18 where the longitudinal edge portions 25 form leg cuffs (see for example Fig. 2). Where no gathering is desired, for example in ,ae waist 10 portions 20, 22, the elastic band remains unadhered to the pocket.

The backing sheet 3 6 presents a longitudinal free edge portion 4 2 which terminates short of the longitudinal edge 15 portion of the diaper. In this manner, the longitudinal edge portion 25 of the diaper consists essentially of nonwoven material which is soft on the skin and which has a tendency to absorb any perspiration which may form.

In order to hinder leakage of liquid from the absorbent core 38, it is advantageous if the facing sheet 34 and the backing sheet 3 6 are adhered together at the longitudinal edges of the absorbent core, as denoted by reference numeral 44 in Figs. 3 to 6.

In the embodiment shown in Fig. 3, the longitudinal free edge portion 42 of the backing sheet 3 6 overlaps the longitudinal free edge portion 40 of the facing sheet, whilst in Fig. 4, the longitudinal free edge portion 40 of 30 the facing sheet overlaps the longitudinal free edge portion 42 of the backing sheet 36. In both embodiments, the longitudinal free edge portion 42 of the backing sheet terminates in the vicinity of the elastic band 24. In the embodiment illustrated in Fig. 5, however, the longitudinal 35 free edge portion 4 2 of the backing sheet 3 6 terminates in the vicinity of the longitudinal edge of the absorbent core 7 38, i.e. in the shown example in the vicinity of the elastic chord 16 of the inner cuff 14. At the same time, the facing sheet 34 extends around the elastic band 24, with the longitudinal free edge portion 40 of the facing 5 sheet 34 terminating in the vicinity of the longitudinal free edge portion 42 of the backing sheet 36. A particular advantage with this embodiment is that the leg cuff, i.e. the region which extends from the longitudinal edge portion 25 of the diaper to the inner cuff 14, consists essentially 10 of nonwoven material. This implies that the entire leg cuff is "breathable", thereby providing more comfort to the wearer.

In Fig. 6, an alternative embodiment of a breathable leg 15 cuff is illustrated. In said figure, both the facing sheet 34 and the backing sheet 3 6 terminate in the vicinity of the absorbent core 38. The leg cuff is formed in this case by an additional sheet 46 of nonwoven material. One lateral edge portion of the additional sheet 4 6 is inserted between 20 the longitudinal free end portions 40, 42 of the facing sheet and backing sheet respectively. The remaining longitudinal free edge portion of the additional sheet 46 is folded under and adhered to the underside of the additionul sheet to thereby form the pocket for the elastic 25 band 24. Preferably, the material of the additional sheet 46 has a basis weight greater than that of the facing sheet 34, for example in the order of 25 to 40 g/m2, preferably about 35 g/m2.

The present invention is not restricted to the embodiments described above and illustrated by way of example in the drawings, but may be varied within the scope of the appended claims. For example, more than one elastic band 24 may be provided in each pocket. In the embodiment shown in 35 Fig. 4, it is conceivable that the elastic means 24 be 8 incorporated in the longitudinal free edge portion 42 the backing sheet 36.

QGfc&Hlaicc. a (VQ5 276514 9 P22085.3rPCT AH 1995-04-12

Claims (6)

CLAIMS: (amended under Article 19 PCT)

1. A disposable diaper comprising an absorbent core disposed between a facing sheet of nonwoven material and a backing sheet , said diaper comprising prest.retched elastic means disposed along longitudinal edge portions of said diaper, whereby said elastic means is accommodated in a pocket of nonwoven material which extends along the entire length of said edge portions , characterized in that said facing sheet presents a longitudinal free edge portion which is folded under and adhered to the underside of the facing sheet to thereby form said pocket within which t-.ho elastic means is accommodated. ;

2. The disposable diaper according to claim 1, characterized in that said backing sheet is made from a liquid impermeable material presenting a longitudinal free edge portion which terminates short of said longitudinal edge portion of the diaper.

3. The disposable diaper according to claim 1 or 2, characterized in that the diaper is provided with a pair of inner cuffs extending longitudinally along the diaper.

4. The disposable diaper according to claim 2 or 3, characterized in that said longitudinal free edge portion of the backing sheet overlaps the longitudinal free edge portion of the facing sheet . N.Z. PATENT OFFICE 1 - MAY 1988 Rj-Crrvfio \ • urnnrn ourrx ^AHTIPI C 1Q\ 276514 10

5. The disposable diaper according to claim 3, characterized in that said longitudinal free edge portion of the backing sheet terminates in the vicinity of the absorbent core , and in that the longitudinal free edge portion of the facing sheet I terminates in the vicinity of the longitudinal frse.. edge portion of the backing sheet

6. A disposable diaper substantially as herein described with reference to the accompanying drawings. END OF CLAIMS