AU740678B2 - Corrugated top layer for absorbent articles - Google Patents

Description

r1uuWu 1 WI Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: 16362/99 Lodged: 9 FEBRUARY 1999 0 *.0S Invention Title: CORRUGATED TOP LAYER FOR ABSORBENT ARTICLES The following statement Is a full description of this Invention, Including the best method of performing It known to us 1 CORRUGATED TOP LAYER FOR ABSORBENT ARTICLES The invention relates to an absorbent sanitary product for the absorption of body fluid, such as for example sanitary napkins, diapers, incontinence articles or the like, having a liquid proof back covering layer, a top liquid-permeable covering layer and an absorbent body inserted therebetween.

Sanitary products of this type are known. An example of such a product is disclosed in GB 2023067. They are all provided with a liquid-proof covering layer on the back and a liquid-permeable covering layer on the top with an absorbent body inserted between these two layers.

The covering layer on the back usually consists of a thin polyethylene foil.

The liquid-permeable covering layer is mostly of nonwoven material, but perforated foils can also be used.

Normally the absorbent body is produced of cellulosic flocs or so-called airlaid-material.

oooo° S 15 In addition of the basic absorptive capacity of the absorbent body the product's technical features of the body-facing covering layer such as the tactile softness, absorbing time in relation to the body liquids, the distribution over the sanitary product and the rewet properties are of vital importance. The nonwoven covers normally used for the body-facing cover layer are comparable in most of S: 20 the above-mentioned features.

The previously mentioned perforated foils have been improved in their absorptive capacity and in the visual impression after admission of menstruation liquid for instance, whereas impairments might occur by the plastic-like character of the perforated foils which causes perspiration.

Above-mentioned properties of the body-facing covering layer regarding the absorbing time and distribution of incurring body liquids and rewetting have a major impact on the leaking safety of the respective sanitary product. Due to the technical standard a variety of measures are known which influence these factors positively. For instance a transport layer has been inserted under the body-facing covering layer to improve the absorbing time and the rewet properties.

Improvements on the liquid distribution in the longitudinal direction of mentioned sanitary products which lead to an increased safety against lateral leakage of the body liquid have been substantially obtained by impressed, longitudinal lines on the surface of a sanitary napkin.

A substantial contribution regarding the sanitary product's leaking safety are so-called cuffs, which, arranged on both of the lateral longitudinal margins of the absorbent body, form a liquid barrier that stays upright by means of elasified material and hinders lateral leakage of the body liquid. While there cuffs greatly increase the leaking safety, they considerable complicated the production of sanitary napkins, diapers, incontinence articles and the like.

From the reference GB-A-20 23 067 it is also known to provide the liquidpermeable top sheet with a plurality of folds following the longitudinal direction of the product. These folds are evenly distributed over the width of the sanitary product. The foot areas of the folds are attached to the absorbent body of the sanitary product.

It is an object of the invention to modify sanitary products of the known type in a manner that the arrangement of folds is optimized concerning the distribution and absorption of body liquids on the one hand and low manufacturing efforts concerning the pleating of a top sheet on the other hand.

According to the present invention, there is provided a sanitary product for 20 the absorption of body liquids including a top liquid-permeable covering layer, a liquid-proof back covering layer, and an absorbent body inserted between the back and top covering layers, the sanitary product having a longitudinal direction and a center plane which bisects the sanitary product through the top layer, absorbent body and back layer in the longitudinal direction, wherein the top covering layer in the area of the absorbent body is arranged in two or more folds following the longitudinal direction of the sanitary product, wherein foot areas of the folds, directing towards the absorbent body, are attached to the absorbent body or to a support layer inserted between the absorbent body and the top covering layer, wherein the foot areas of the folds are glued or welded on the absorbent body or the support layer and wherein several folds are provided on two lateral strips and whereas there is at least a strip without folds in the top layer between the center plane and the folds provided on at least one of the two lateral strips.

Preferably, center folds are provided symmetrically to the center plane whereas a strip without folds remains between the center folds and the folds provided on the two lateral strips.

Preferably, center folds are provided symmetrically to said center plane.

Preferably, said top liquid-permeable covering layer is of a non-woven material.

Preferably, the foot areas of the folds are glued or welded on the absorbent 10 body or the support layer over a width of 0.2-10 mm.

9 :•.Preferably, 2-10 folds are provided on said two lateral strips.

Preferably, the foot area of two adjacent folds are fixed with a mutual spacing of from 1 to 20 mm.

Preferably, the height of the folds is from 1 to 20 mm in no-load condition.

999*99 The following statements relate to exemplary embodiments of the invention.

Furthermore it is noted that the folds in most areas of the covering layer 999o built a spacing between themselves and the absorbent body underneath, which improves both the absorptive or penetrating action of the body liquid into the 20 absorbent body and the rewet properties. The visual impression after admission of for instance menstruation liquid will also be improved because raised folded areas are not in contact with the liquid-soaked absorbent body. The flexibility of the folds will also have an effect on the softness of the body-facing surface of the sanitary product thus providing a higher wearing comfort and the natural comfort and the natural touch.

Due to the fixing of folds these are stabilised in such a manner, that the created positive effects will remain, even after storage in pressed condition and over an extended wearing period.

As noted above the foot area of the folds can be directly fastened by gluing or welding on the absorbent body or on a support layer which is inserted between the covering layer and the absorbent body. This support layer helps to improve the functional features of the folds regarding the further transmission of liquid and the rewet properties.

In order that the invention might be more fully understood, embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective partial view of a sanitary napkin known from prior art, Fig. 2 is a cross-section of a prior art sanitary napkin according to Fig. 1 with a partial enlargement, Fig. 3 is a cross-section of a further known sanitary napkin known from the S prior art, Fig. 4 is a cross-section of a sanitary napkin according to an embodiment of the invention; and Fig. 5 is a schematic perspective view of a sanitary napkin's surface in a further embodiment of the invention.

As can be seen in the attached drawings, the different types of the respective sanitary napkin all have a base structure which is identical in vital parts. The back is provided with a liquid-proof covering layer, the underwear protecting foil 1, which is underneath the absorbent body 2 consisting of a pad of 20 cellulosic flocs in the area of its back 3 i.e. on the body-averting side of the sanitary napkin when worn. Furthermore the longitudinal edges 4 of the underwear protecting foil 1 reach over the later margin 5 of the absorbent body.

A support layer 7 for instance made of nonwoven material is arranged on the front surface area 6. The longitudinal edges 8 of this support layer 7 also reach over the lateral margin 5 of the absorbent body 2 and overlap the longitudinal edges 4 of the underwear protecting foil 1. Both of these parts are glued together in the usual manner in the overlapping area.

On top of support layer 7 a liquid-permeable covering layer 9 is arranged which is provided with folds 10 as later described in detail. The prior art sanitary napkin shown in Fig. 1, 2 and the embodiments of the invention shown in Figure 4 are a so-called "fully wrapped sanitary napkin", which consists of a covering layer 9 for instance of polypropylene card web and encloses the absorbent body 2 and the support layer 7. Covering layer 9 is folded on the back 3 and attached to the center by means of a glued connection 11.

The prior art in Fig. 3 and the embodiment of the invention in Figure 5 are provided with lateral wings 12, which are formed by overlapping flaps 13, 14 being connected to the lateral margins of covering layer 9 on the front and covering layer 15 on the back. The covering layer 15 might be of nonwoven material such as the case in the prior art shown in Fig. 3. which shall be provided with a separate underwear protecting foil 1. The covering layer can also consist of liquid-proof material, for instance of polyethylene foil, thus taking over the underwear protecting foil's function and omitting it.

Now the different configurations of folds used in illustrated sanitary napkins shall be explained in more detail.

The folds 10 are formed by a suitable folding device in the sanitary napkin's production machine so that the foot areas 16 are located on support layer 7 with a spacing of 1 to 20 mm in the transversal direction of the sanitary napkin. A spacing of 3 to 5 mm has proven to be most practicable. The foot areas 16 are attached to the support layer 7 by means of longitudinal glue strips 17, for instance of spray adhesive. Between each adjacent foot area 16 the fold 20 10 stands upright with a height H ranging from 1 to 20 mm. The most practicable values for the height were also in the area of 3 to 5 mm. The foot width F defined by the glue strips 17 can vary from 0.2 to 10 mm depending on the spacing A and the height H, whereas it must be considered that the maximum foot width F is half the spacing A. With spacing A and height H in the range of 3 to 5 mm, foot widths of 0.5 to 1 mm proved to be successful.

In the prior art shown in Fig. 1 through 3, eight folds are provided evenly spread over the entire width of the absorbent body's surface, working with a spacing A of approx. 6 mm between the folds.

In the embodiment of the invention shown in Fig 4, within two lateral strips 18 are provided two folds 10, respectively, which run in the longitudinal direction of the sanitary napkin and which have a spacing A and height H of approx. 6 mm.

6 The remaining center strip 19 between both lateral strips 18 consists of a liquidpermeable covering 9 which lays evenly on top of the support layer 7 to which it is additionally fastened by a center glue strip 17'. A liquid-permeable glueing over the entire area can also be obtained with a small quantity of adhesive.

The further embodiment of a sanitary napkin shown in Fig. 5, has in addition to folds 10 on both lateral strips 18, further folding configurations, symmetrical to center plane L consisting of three folds 10. A strip without folds remains between the center folds 10 and the lateral folds Like noticeable form the cross-sections according to Fig 2. through 4, the top of the folds 10, the chamfers 21 in between and the tubes 22 which are underneath the folds 10 between the glued foot areas 16 built channel for the longitudinal distribution of body liquids admitted on the sanitary napkin.

In closing, it has to be pointed out that the individual components of the sanitary napkin of the embodiments of the invention shall be of suitable known oo°° material according to known criteria for the production of these sanitary products.

S Suitable constructional measures shall be utilized. For instance it is advisable to glue the strips 17 on the support layer surface in such manner, that they hinder the penetration of liquids only to a very small extent that the absorbent surface of the sanitary napkin still remains relatively high. Spray adhesive or small threads of 20 melt-blown adhesive can be used, another possibility is welding or sealing by laser, ultrasound or heat.

Claims (9)

1. A sanitary product for the absorption of body liquids including a top liquid- permeable covering layer, a liquid-proof back covering layer, and an absorbent body inserted between the back and top covering layers, the sanitary product having a longitudinal direction and a center plane which bisects the sanitary product through the top layer, absorbent body and back layer in the longitudinal direction, wherein the top covering layer in the area of the absorbent body is arranged in two or more folds following the longitudinal direction of the sanitary product, wherein foot areas of the folds, directing towards the absorbent body, are attached to the absorbent body or to a support layer inserted between the absorbent body and the top covering layer, wherein the foot areas of the folds are glued or welded on the absorbent body or the support layer and wherein several folds are provided on two lateral strips and whereas there is at least a strip without folds in the top layer between the center plane and the folds provided on at least one of the two lateral strips.

2. The sanitary product according to claim 1, wherein center folds are provided symmetrically to the center plane whereas a strip without folds remains between the center folds and the folds provided on the two lateral strips.

3. The sanitary product according to claim 2, wherein 2-10 center folds are provided symmetrically to said center plane.

4. The sanitary product according to any one of claims 1 to 3, wherein said top liquid-permeable covering layer is of a non-woven material.

The absorbent article according to any one of claims 1 to 4, wherein the foot areas of the folds are glued or welded on the absorbent body or the support layer over a width of 0.2-10 mm. 8

6. The sanitary product according to any one of claims 1 to 5, wherein 2-10 folds are provided on said two lateral strips.

7. The absorbent article according to any one of claims 1 to 6, wherein the foot area of two adjacent folds are fixed with a mutual spacing of from 1 to mm.

8. The absorbent article according to any one of claims 1 to 7, wherein the height of the folds is from 1 to 20 mm in no-load condition. S

9. An absorbent article substantially as hereinbefore described and illustrated with reference to either Figures 4 or 5 of the accompanying drawings. DATED this 10 th day of September 2001 THE PROCTER AND GAMBLE COMPANY WATERMARK PATENT AND TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA LCG/RJSMEH P4806AU LCG/RJS/MEH P4806AU00.DOC