WO2000071068A1

WO2000071068A1 - Absorbent pad with optimum shaped core

Info

Publication number: WO2000071068A1
Application number: PCT/KR2000/000508
Authority: WO
Inventors: Doo-Hong Kim; Hyeong-Beom Kim; Eo-Yeon Hwang; Eun-Jung Kang
Original assignee: Yuhan-Kimberly Ltd.
Priority date: 1999-05-20
Filing date: 2000-05-20
Publication date: 2000-11-30
Also published as: AU4621700A; MXPA01011523A; KR100628399B1; KR20000074435A

Abstract

An absorbent pad having an optimum shaped absorbent core comprised of a plurality of concave edges and encased between top and back sheets forming an outer margin which has a plurality of concave edges corresponding to the plurality of concave edges of the core.

Description

ABSORBENT PAD WITH OPTIMUM SHAPED CORE

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to a personal hygiene absorbent article and, more particularly, to an absorbent pad having an optimum shaped absorbent core and an optimum shaped outer margin.

Description of the Prior Art

Sanitary napkins and incontinence pads (hereinafter collectively referred to as "pads") are well known in the personal care and hygiene art. These pads are generally constructed with a liquid pervious top sheet, a liquid impervious back sheet and an absorbent core disposed between the top and back sheets. The liquid pervious top sheet allows menstrual fluids or urine to seep through to the absorbent core which is designed to retain the liquid discharges while the liquid impervious back sheet prevents further seepage and soiling of the user's clothing.

As the absorbent core is intended to retain the liquid discharges, exposure of the core results in leakage and outwardly exposed core materials with retained menstrual fluids or urine is aesthetically and practically unpleasant. To seal off the absorbent core in between the top and back sheets, the respective outer peripheral edges of the top sheet and the back sheet are bonded together, thereby encasing the core. To this end, the widths, lengths and overall surface areas of the top and back sheets are necessarily larger than that of the core. The portions of the outer peripheral edges of the top and back sheets which extend beyond and around the periphery of the core and which are bonded together, are referred to collectively as the "outer margin. " The width of this outer margin is either constant or variable along the periphery of the core.

Some conventional pads further comprise two flaps defined by the top and back sheets, each flap extending laterally and outwardly from adjacent opposite side edges of a longitudinally central zone of the core. Pads having flaps are provided with adhesive on a back surface of each flap. In use, such pads are laid with the back sheet side down on an inner surface of the crotch portion of a user's panty. The flaps are then folded onto an outer surface of the crotch portion of the panty and the pad is secured thereto with the adhesive.

Problems which have existed and continue to exist in the art are the ability of conventional pads to conform to the natural curves of a user's body which correspond to and are directly in contact with the crotch portion of a panty (referred to herein as the "contact zone") while maintaining comfort and performing their intended function of absorbing and retaining liquid discharges. The overall outline of the outer margin described above has undergone constant modification in the art in attempts to find the optimum configuration and dimensions which can be folded to conform to the contact zone, while retaining all features of pad function.

In a conventional pad, the longitudinal opposite ends are adapted to fold and curve upwardly in a U-shape so that the pad conforms to the contact zone when inserted in use between the contact zone and the panty. As the width of the pad correspond-ing to the contact zone is generally wider than the actual width of the contact zone, the longitudinally central portion of the pad is compressed by opposing forces exerted from both thighs of the user. The compression causes wrinkles and folds in the width of the contact zone.

The longitudinal edges of the absorbent core and outer margin in a conventional pad are generally straight. When flaps, present in such conventional pads, are folded onto the outer surface of the crotch portion of a panty, the flaps are folded up to the longitudinally opposite edges of the core because the core is generally larger in width than the crotch portion of the panty, and portions of the outer margin longitudinally adjacent the flaps are also folded concurrent with the flaps.

When the pad is worn in this fashion over time, portions of the back sheet of the outer margin may be urged against the panty while longitudinally opposite ends of the pad are curved upwardly in a U-shape. This causes the flaps to be pulled outwardly and gradually apart from their original, intended positions, undermining their inherent function which is to fix the pad to the crotch portion of the panty.

Further, while the longitudinal opposite ends of a con-ventional pad are curved upwardly in the U-shape when worn, the flaps and portions of the outer margin folded concurrent with the flaps create downward forces resistant to the upwardly curving force. This continued downward force unfolds the U-shape of the pad such that it disengages away from the user's body, making it uncomfortable and increasing the possibility of leakage. And, due to portions of the longitudinal outer margin being folded concurrent with the flaps, even widths in areas beyond the longitudinally central zone of the pad become narrowed which increases the overall possibility of lateral leakage.

Even in conventional pads without flaps, the longitudinal outer margins adjacent the outer margin of the central zone are folded as the outer margin of the central zone is compressed which give rise to the same problems exhibited in conventional pads with flaps, as described above.

A variation of known conventional pads includes one having a core configured in an hour-glass shape in which the core's longitudinally central zone has a narrower width than its longitudinally opposite ends, and which has straight, longitudinal edges for its outer margin. Since the width at the longitudinally central zone of the core is narrower than at its longitudinally opposite ends, less force is transversely applied to the central zone of the core, thereby enhancing comfort and fit. However, since the outer margin at the central zone of such pads is also folded along with the outer margin adjacent the central zone, the above-described problems are not avoided. Further, the reduction of the width at the central zone of an hour-glass shaped core exhibits a greater possibility of lateral leakage.

This disclosure presents a shaped absorbent pad which provides a simple solution to the problems which exist in the art with all the advantages of and meeting the following objectives.

Objects of the Invention

Accordingly, it is a general object of the present invention to provide improved sanitary napkins and incontinence pads for personal care and hygiene.

Another object of the present invention is to provide an absorbent pad having an optimized overall shape which is adapted to conform, in an optimum manner, to the shape of the user's contact zone, while retaining all the benefits of good absorption and retention of liquid discharges, and providing comfort to the user.

A further object of the present invention is to provide an absorbent pad which overcomes problems found in the art during use of conventional pads, thereby providing an absorbent pad which is able to maintain its intended physical shape consistently during use.

Yet another object of the invention is to provide an absorbent pad having an improved core shape comprising concave edges adjacent the central portion of its longitudinally opposite sides.

An additional object of the invention is to provide an absorbent pad having an outer margin which comprises a plurality of concave portions corresponding to a plurality of concave edges of the core.

Still a further object of the present invention is to provide an absorbent pad having laterally extending wings wherein a plurality of concave edges of the core correspond to four portions at which the wings begin to transversely extend from the longitudinally opposite side edges of the top and back sheets and where the wings and the longitudinal side edges of the top and back sheets intersect.

Yet another object of the present invention is to provide an absorbent pad having wings and an absorbent core with an improved shape comprising four concave edges which delineate a central portion extending laterally and outwardly at a longitudinally central zone of the core, and further comprising four concave portions in the outer margin which correspond to the four concave edges of the core and which delineate the wings, for maintaining the inherent function of the wings in consistently fixing the pad to the crotch portion of the panty of a user.

Other objects of the present invention will be apparent to those skilled in the relevant art following a study of this disclosure.

SUMMARY OF THE INVENTION

One aspect of the present invention is an absorbent pad comprising a liquid permeable top sheet further comprising a plurality of concave corner edges, a liquid impermeable back sheet further comprising a plurality of concave back sheet edges, and an absorbent core disposed between the top sheet and the back sheet, with the core further comprising a plurality of concave edges. The narrowest width between two transversely opposing concave corner edges of the top sheet is equal to or less than the widest width at a longitudinally central zone of the absorbent core and the narrowest width between two transversely opposing concave back sheet edges is equal to or less than the widest width at the longitudinally central zone of the absorbent core.

Another aspect of the invention is an absorbent pad comprising a liquid permeable top sheet further comprising a plurality of concave corner edges, a first lateral wing and a second lateral wing, a liquid impermeable back sheet further comprising a plurality of concave back sheet edges, a first lateral back sheet wing and a second lateral back sheet wing, and an absorbent core disposed between the top sheet and the back sheet, with the core further comprising a plurality of concave edges.

The peripheral edges of the top and the back sheets are sealed to form an outer margin around the peripheral edge of the absorbent core. The absorbent pads of the present invention can have a top sheet comprising four concave corner edges, a back sheet comprising four concave back sheet edges, and an absorbent core comprising four concave edges.

In the absorbent pads of the present invention, the depth of each concave corner edge of the top sheet, concave back sheet edge of the back sheet and concave edge of the absorbent core is at least 3 mm, and preferably at least 5 mm. The absorbent pads of the present invention can have the transverse width between opposing concave edges of the absorbent core between about 5 cm to about 15 cm, and preferably between about 5 cm to about 10 cm. The width of the longitudinal central portion of the absorbent core of the present invention can be larger than the width between two transversely opposing concave edges of the absorbent core.

The invention is described in further detail below in conjunction with the figures which are briefly described immediately below.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a plan view of one embodiment of the sanitary napkin of the present invention primarily showing the liquid pervious top sheet with the absorbent core depicted in phantom lines.

Fig. 2 is a plan view of the liquid impervious back sheet of the embodiment shown in Fig. 1, featuring adhesive strips disposed on the lateral wings.

Fig. 3 is a cross sectional view of the embodiment shown in Fig. 1 taken along line 3-3.

Fig. 4 is a cross sectional view of the embodiment shown in Fig. 3 with lateral wings folded in position over a crotch portion of a panty.

Fig. 5 is a perspective view of the sanitary napkin shown in position with respect to a panty.

Fig. 6 is a plan view of another embodiment of the sanitary napkin of the present invention having no wings, and primarily depicts the liquid pervious top sheet with the absorbent core drawn in phantom lines.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described with reference to Fig. 1. Fig.

1 shows a plan view of sanitary napkin 10 having top sheet 20, absorbent core 30

(shown predominantly in phantom lines) and back sheet 40. Top sheet 20 is a liquid pervious layer which allows menstrual fluids to seep through to absorbent core 30. Top sheet 20 is comprised of longitudinal edges 21, transverse edges 22 and lateral edges 23. Each longitudinal edge 21 is joined to its adjacent transverse edge 22 by concave corner edges 24. Top sheet 20 is further comprised of lateral wings 25 and 25 ' . Each wing is defined by corresponding transverse edges 22 and lateral edges 23. Each wing is adapted to be folded along corresponding lines 26 and 26' which are lines formed by connecting opposing corner edges 24 in a longitudinal direction.

A portion of absorbent core 30 is displayed in Fig. 1 by a corner of top sheet 20 being opened and raised. Absorbent core 30 is depicted as being disposed between liquid pervious top sheet 20 and liquid impervious back sheet 40. Absorbent core 30 (as shown predominantly by phantom lines) comprises a plurality of concave core edges 34 and lateral core edges 33 and 33' . The plurality of concave core edges 34 each correspond to a concave corner edge 24 of top sheet 20. The overall size or surface area of the corresponding top and back sheets 20 and 40 are larger than absorbent core 30 as shown in Fig. 1 to provide a peripheral outer margin for sealing. Fig. 1 shows lateral core edges 33 and 33' at the longitudinally central zone of absorbent core 30 as in substantial longitudinal alignment with lines 26 and 26' , respectively, which are formed by connecting opposing concave corner edges 24 in a longitudinal direction in top sheet 20. Accordingly, even if wings 25 and 25' are folded against lateral core edges 33 and 33' , longitudinal edges 21 adjacent the wings are not folded along with the wings.

Fig. 1 also shows that the width between lateral core edges 33 and 33' is substantially equal to the width defined by lines 27 and 27' which are lines formed by connecting opposing concave corner edges 24 of top sheet 20 in a transverse direction. It is to be noted that when the transverse width between opposing lateral core edges 33 and 33' is substantially equal to or slightly larger than the width of lines 27 and 27', an object of the present invention is achieved.

Fig. 2 is a planar view of back sheet 40 featuring adhesive strips 47 and 48. Back sheet 40 is structurally comprised of longitudinal back sheet edges 41 , transverse back sheet edges 42 and lateral back sheet edges 43. Each longitudinal back sheet edge 41 is joined to its adjacent transverse back sheet edge 42 by concave corner back sheet edges 44. Back sheet 40 is further comprised of lateral back sheet wings 45 and 45 ' . Each back sheet wing is defined by corresponding transverse back sheet edges 42 and lateral back sheet edges 43. Each back sheet wing is adapted to be folded along corresponding lines 46 and 46' which are lines formed by connecting opposing concave corner back sheet edges 44 in a longitudinal direction.

As shown when Figs. 1 and 2 are viewed together, top sheet 20 and back sheet 40 have the identical shape and constituent structural portions which conform to each other when the two are laminated together at the outer margin which extends completely around the periphery of core 30 and sanitary napkin 10.

Fig. 3 is a cross sectional view of the embodiment shown in Fig. 1 taken along line 3-3. Top sheet 20 is shown comprised of, by way of example, lateral wing 25 delineated by one concave corner edge 24 and terminating at lateral edge 23. Lateral wing 25' has the same relative physical relationship. Back sheet 40 is depicted as comprising, again by way of example, lateral back sheet wing 45 which is delineated with concave corner back sheet edge 44 and terminating at lateral back sheet edge 43. Lateral back sheet wing 45' also has the same physical relationship as back sheet wing 45.

Disposed between top sheet 20 and back sheet 40 is core 30. Fig. 3 shows the width between lateral core edges 33 and 33' at the longitudinal central zone of absorbent core 30 is substantially equal to the width of top sheet 20 defined by a line formed between opposing concave corner edges 24 in a transverse direction. Fig. 3 also shows that the width between lateral core edges 33 and 33' is substantially equal to the width of back sheet 40 defined by a line formed between opposing concave corner back sheet edges 44 in a transverse direction.

Fig. 4 is another cross sectional view of the embodiment shown in Fig. 3 with lateral wings and back sheet wings (25, 25', 45 and 45') folded in position over the crotch portion of panty 70. Adhesive strip 47 is affixed to the outside, while adhesive strips 48 is affixed to the inside of panty 70, in a conventional manner. As Fig. 4 shows, the present invention is adapted to form smooth folding edges by the reinforcement provided by the wings of the core extending at its lateral edges to the point of alignment with the longitudinal edges of both the top and back sheets.

Fig. 5 is a perspective view of sanitary napkin 10 shown in position with respect to panty 70. Fig. 5 demonstrates that concave core edges 34 correspond to portions (i.e. , concave corner edges 24 and concave corner back sheet edges 44) at which the wings begin to transversely extend from the longitudinal opposite side edges of the top and back sheets (20, 40). As it can be seen from Fig. 5 showing wings 25 and 25' attached on the outer surface of the crotch portion of the panty 70, the longitudinal outer margin adjacent the wings are not folded along with the wings.

One skilled in the art will appreciate that the selection of the positions for the concave corner edges 24 of the top sheet and the corresponding concave corner back sheet edges 44 will vary depending on the shape or size of the wings. Additionally, the varying sizes of panties and the sizes of the users must also be considered.

Fig. 6 is a plan view of another embodiment of the sanitary napkin of the present invention and shows sanitary napkin 110 having top sheet 120, absorbent core 130 (shown predominantly in phantom lines) and back sheet 140. Top sheet 120 is a liquid pervious layer which allows menstrual fluids to seep through to absorbent core 130. Top sheet 120 is comprised of longitudinal edges 121 and lateral edges 123. Each longitudinal edge 121 is joined to its adjacent lateral edges 123 by concave top sheet edges 124.

A portion of absorbent core 130 is displayed in Fig. 6 by a corner of top sheet

120 being opened and raised. Absorbent core 130 is shown disposed between liquid pervious top sheet 120 and liquid impervious back sheet 140. Absorbent core 130 (as shown by phantom lines) comprises a plurality of concave core edges 134 and lateral core edges 133 and 133'. The plurality of concave core edges 134 each correspond to a concave top sheet edge 124 of top sheet 120. The overall size or surface area of the corresponding top and back sheets 120 and 140 are larger than absorbent core 130 to provide a peripheral outer margin for sealing. Fig. 6 shows lateral core edges 133 and 133' as in substantial longitudinal alignment with lines 126 and 126', respectively, which are formed by connecting opposing concave top sheet edges 124 in a longitudinal direction in top sheet 120. Accordingly, even if lateral edges 123 are folded against lateral core edges 133 and 133' , longitudinal edges 121 adjacent the lateral edges 123 are not folded together.

Fig. 6 also shows that the width between lateral core edges 133 and 133' at the longitudinally central zone of absorbent core 130 is substantially equal to the width defined by lines 127 and 127' which are lines formed by connecting opposing concave top sheet edges 124 of top sheet 120 in a transverse direction. As noted for the first embodiment with wings above, when the transverse width between opposing lateral core edges 133 and 133' is substantially equal to or slightly larger than the width of lines 127 and 127', an object of the present invention is also achieved with the second embodiment without wings.

Referring to Figs. 1 and 6 together, when the transverse width of between lateral core edges 33 and 33' or between lateral core edges 133 and 133' is substantially equal to or greater than the width of line 27, 27' , 127 or 127' , one object of the present invention is achieved. As the width of the side margin is generally at least about 3 mm and preferably more than 5 mm, the depth of the depression of concave corner edges 24 and concave corner back sheet edges 44 is varied accordingly.

As described above, concave portions in both the outer margin and the absorbent core prevent longitudinal outer margins adjacent longitudinally central zones of the pad from folding along with the outer margin or wing located at the longitudinal-ly central zone of the pad, folded in a downward direction with respect to a panty. Further, since the width of the absorbent core at the longitudinally central zone of the pad is enlarged up to the width of the outer margin or width corresponding to the depth of the depression of the concave portion of the top and back sheets, the possibility of lateral leakage at the longitudinally central zone of the core is minimized.

Various modifications and alterations to the present inven-tion may be appreciated based on a review of this disclosure. These changes and additions are intended to be within the scope and spirit of this invention as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. An absorbent pad comprising:

a liquid permeable top sheet further comprising a plurality of concave comer edges;

a liquid impermeable back sheet further comprising a plurality of concave back sheet edges; and

an absorbent core disposed between said top sheet and said back sheet, said core further comprising a plurality of concave edges; wherein the narrowest width between two transversely opposing concave comer edges of said top sheet is equal to or less than the widest width at a longitudinally central portion of said absorbent core and the narrowest width between two transversely opposing concave back sheet edges is equal to or less than the widest width at the longitudinally central portion of said absorbent core.

2. The absorbent pad of claim 1, wherein said pad is either a female sanitary napkin or an incontinence pad.

3. The absorbent pad of claim 1 , wherein said plurality of concave comer edges of said top sheet comprises four concave comer edges.

4. The absorbent pad of claim 1, wherein said plurality of concave back sheet edges of said back sheet comprises four concave back sheet edges.

5. The absorbent pad of claim 1 , wherein said plurality of concave edges of said absorbent core comprises four concave edges.

6. The absorbent pad of claim 1 , wherein the depth of each concave comer edge of said top sheet, concave back sheet edge of said back sheet and concave edge of said absorbent core is at least 3 mm.

7. The absorbent pad of claim 1 , wherein the depth of each concave comer edge of said top sheet, concave back sheet edge of said back sheet and concave edge of said absorbent core is at least 5 mm.

8. The absorbent pad of claim 1 , wherein the transverse width between opposing concave edges of said absorbent core is between about 5 cm to about 15 cm.

9. The absorbent pad of claim 1 , wherein the transverse width between opposing concave edges of said absorbent core is between about 5 cm to about 10 cm.

10. The absorbent pad of claim 1, wherein the width of the longitudinal central portion of said absorbent core is larger than the width between two transversely opposing concave edges of said absorbent core.

11. An absorbent pad comprising:

a liquid permeable top sheet further comprising a plurality of concave comer edges, a first lateral wing and a second lateral wing;

a liquid impermeable back sheet further comprising a plurality of concave back sheet edges, a first lateral back sheet wing and a second lateral back sheet wing; and

an absorbent core disposed between said top sheet and said back sheet, said core further comprising a plurality of concave edges; wherein the peripheral edges of said top and said back sheets are sealed to form an outer margin around the peripheral edge of said absorbent core, and wherein the narrowest width between two transversely opposing concave comer edges of said top sheet is equal to or less than the widest width at a longitudinally central portion of said absorbent core and the narrowest width between two transversely opposing concave back sheet edges is equal to or less than the widest width at the longitudinally central portion of said absorbent core.

12. The absorbent pad of claim 11, wherein said pad is either a female sanitary napkin or an incontinence pad.

13. The absorbent pad of claim 11 , wherein said plurality of concave comer edges of said top sheet comprises four concave comer edges.

14. The absorbent pad of claim 11 , wherein said plurality of concave back sheet edges of said back sheet comprises four concave back sheet edges.

15. The absorbent pad of claim 11 , wherein said plurality of concave edges of said absorbent core comprises four concave edges.

16. The absorbent pad of claim 11 , wherein the depth of each concave comer edge of said top sheet, concave back sheet edge of said back sheet and concave edge of said absorbent core is at least 3 mm.

17. The absorbent pad of claim 11, wherein the depth of each concave comer edge of said top sheet, concave back sheet edge of said back sheet and concave edge of said absorbent core is at least 5 mm.

18. The absorbent pad of claim 11 , wherein the transverse width between opposing concave edges of said absorbent core is between about 5 cm to about 15 cm.

19. The absorbent pad of claim 11 , wherein the transverse width between opposing concave edges of said absorbent core is between about 5 cm to about 10 cm.

20. The absorbent pad of claim 11, wherein the width of the longitudinal central portion of said absorbent core is larger than the width between two transversely opposing concave edges of said absorbent core.