US2896627A - Sanitary napkin - Google Patents

Description

July 28, 1959 K. J. HARWOOD SANITARY NAPKIN 2 Sheets-Sheet 1 Original Filed July 14. 1955 I A fibrous Hait /vial INVENTOR. iidenneihd'flarwood BY I 50%, 2104/ July 28, 1959 K. J. HARWOOD 2,396,627

' SANITARY NAPKIN Original Filed July 14. 1955 2 Sheets-Sheet 2 INVENTOR.

United States Patent SANITARY NAPKIN Kenneth J. Harwood, Neenah, Wis., assignor to KimberlysClark Corporation, Neenah, Wis., a corporation of Delaware 12 Claims. (Cl. 128-290) The present invention relates generally to absorbent pads, and is particularly directed to an improved form of sanitary napkin.

In the manufacture of absorbent pads, such as sanitary napkins, one of the major problems is proper control ofthe flow of the fluids absorbed by the pad, so that such fluid will be prevented from striking through the pad and so that maximum usage of the absorbency of the pad can be realized. It has been found that one of the most eifective means for preventing strike through and for distributing the absorbed fluid throughout .the pad is a non-absorbent baffle sheet appropriately placed in the pad. Such bafiles are generally a fluid-resistant film or sheet of thin material, such as those of the polyethylene type or the like.

However, since such fluid-resistant materials are usually quite smooth, there is a tendency for them to slide relative to the adjacent pad surface, particularly when the pad is deformed to fit the body surface to which it is applied. Consequently, the eifectiveness of the baflle sheet is largely lost in such instances, and there is produced an undesirable bunching and creasing of the fluidresistant film, which may cause considerable discomfort.

It is the principal object of this invention to provide an absorbent pad with a baffle sheet of fluid-resistant material in an improved manner which avoids the above deficiencies. Other objects and advantages of the invention will become apparent from the following disclosure of one embodiment of the invention illustrated in the accompanying drawings, wherein:

Figure 1 is a plan view of the chosen embodiment, with portions of the pad partially displaced to better illustrate the detailed construction of the pad;

Figure 2 is an enlarged sectional view, taken along the line 22 in Figure 1;

Figure 3 is a magnified, cross-sectional view of th bafile sheet used in Figures 1 and 2;

Figure 4 is an enlarged fragmentary view of the baflle sheet;

Figure 5 is a magnified, cross-sectional view of a modified form of bafile sheet; and

Figures 6 and 7 are enlarged fragmentary views of further modifications of the invention.

In, the making of an absorbent pad, bandage, sanitary napkin or the like, it is very important that the absorbed fluid be essentially uniformly distributed throughout the pad, so that there is not a sufiicient concentration of thefluid in any one area to strike through the pad. This is particularly important in connection with sanitary napkins wherein discomfort and staining may readily result froma concentration of fluids on the outer surface of the pad.

Consequently, it is very desirable to provide some means to control the flow of fluids in an absorbent pad, so as to direct such fluids over a maximum area of the pad and to prevent the fluid from striking through the outer surface of the pad. In order to achieve these results, it has been found to be advantageous to provide a bafiie sheet of fiuid-resistant material at some portion of the pad which is spaced from the body side of the pad. However, the use of such baffle sheets has presented other problems, particularly with respect to sanitary napkins.

The prior baffie sheets, which generally have been thin sheets of water-proof material, have been difficult to maintain in fixed relation to the pad body because of their inherently slippery characteristic. Consequently, with absorbent pads such as sanitary napkins, wherein the pad is deformed during use and is almost constantly subjected to moving forces, the bafile sheet slides relative to the pad and thereby loses most of its effectiveness. Further, the thin and slippery baffle sheet often becomes bunched together as it slides out of position and produces an undesirable bulkiness and creasing of the sheet which is very discomforting to the wearer.

The present invention is particularly directed to an absorbent pad construction, including a battle sheet, which overcomes the above difficulties. More particularly, with reference to the drawings, it is seen that one embodiment of the invention is in the form of a sanitary napkin 10, which includes a pad body 12 of absorbent material, a bafile sheet 14, a pair of side strips 16, and a gauze wrapper 18. The illustrated pad body 12 is of a well known form of construction and comprises an elongated body of comminuted fibrous material 2t), sometimes referred to as fluff, and a multi-ply sheet 22 of creped wadding material disposed through an intermediatesection of thefluff, with the sheet 22 being embossed orcorrugated to provide longitudinally extending channel portions for directing the flow of fluids lengthwise of the pad.

A multi-ply creped tissue sheet 24 is disposed on each side of the flutl material 20, and the opposite ends of the pad are pinched together to form a unitary structure of the fluid absorbent flufi and the sheets of creped tissue or wadding. Additionally, the sides of the pad are enclosed substantially the length thereof by the pair of side strips 16, which are also preferably of creped wadding material, wherein the lines of creping extend transversely of the pad.

The bafile sheet 14 is disposed on one surface of the pad body along a substantial portion of the length, being generally coextensive in length with the side strips 16. In the illustrated sanitary napkin, the baffle sheet is disposed on the side of the pad which will be the outer surface when in use, and comprises a thin film of plastic material 14a having a web of fibers 14b embedded therein on at least one side. The frictional surface afforded by the fibrous web 1412 is very advantageous in maintaining the baffle in position in the pad. The engagement of the fibrous web with the creped tissue side strips 16 and with the gauze wrapper 18 is very effective in accomplishing this very desirable result. Further advantages with respect to the prevention of slippage of the baffle sheet will be gained by including a fibrous 'Web on both sides of the plastic film 14a, as shown in Figure 5 of the drawings. In the latter embodiment there is illustrated a baffie sheet 3t) comprising a thin film 32 of fluid-repellant material bonded between two or more webs 34 and 36 of fibers. Thus, there is not only provided a frictional engagement between the upper surface of the baffle sheet and the overlying portions of the side strips and gauze wrapper in the manner of the previously described embodiment, but there will also be frictional contact with the underlying pad body to further prevent slippage of the baffle sheet. However, it is believed that the illustrated duplex construction of plastic film and fibrous web will suflice in most instances.

For sanitary napkin use, Where bulk is an important factor, it is preferred that 'the embodiment of Figure 1 be employed, wherein the composite bafile sheet has an average thickness of between 2.0 and 6.0 mils and a basis weight within the range of from about 3.0 to 40.0 lbs. per standard ream of 2880 square feet. The film should be from 0.15 to 1.50 mils, preferably from about 0.33 to 0.75 mils, and the fiber Web on one side of the plastic film should preferably have a weight of from about 2.0 to about 20.0 lbs. per 2880 square feet. The fiber may advantageously be in the form of a creped tissue paper web, with a preferred crepe ratio for such web being from about 1.0 to 2.3. The creped web lends itself to flexing with the baflie sheet without seriously aifecting the bond therebetween, and also enhances the frictional engagement between the baflie and the adjacent portions of the sanitary napkin. In one example, satisfactory use has been made of a polyethylene sheet having an average thickness of about 1.0 ml, and faced with a creped tissue sheet having an uncreped basis weight of 7.6 lbs. per 2880 square feet and a crepe ratio of 1.2, wherein the fibers of the tissue are partially embedded into the polyethylene sheet, as seen in Figure 3.

The smooth or film side 14a of the fiber-faced baffle sheet 14 is disposed'in facing relation to the crepe wadding plies 24 on the outside of the pad body, that is, the surface of the sanitary napkin which will be disposed away from the body when inuse. The side strips 16 are disposed in overlapping relation to opposite edge portions of the fibrous outer surface 14b of the baflle sheet, so that the frictional engagement between the two fibrous surfaces will prevent relative movement therebetween.

A gauze wrapper 18 or the like is disposed about the pad body, preferably with the overlapped portion of the wrapper overlying the side of the pad.which includes the bafile sheet 14. This not only positions the wrapper fold away from the body of the wearer, which is desirable for greater comfort, but also places a double thickness of the wrapper in position to provide a firmer engagement with the baflle covered portion of the pad to prevent relative movement of the fiuid-repellant baffle sheet.

It is seen, therefore, that there is provided an improved arrangement for a bafiie sheet in an absorbent pad, which insures a firm positioning of the fluid resistant sheet relative to the pad. In the embodiment of Figures 1 and 2, the fiber-faced baflle sheet 14 is frictionally engaged along its marginal portions by the side strips 16, and is also held across its outer surface by means of the gauze wrapper 18.

It should be recognized, however, that while this particular arrangement is advantageous in connection with sanitary napkins, a more simplified construction may be employed without departing from the principles of the present invention. For example, the baflle sheet can be held in place either by the side strips 16 alone, or by the gauze wrapper alone, where it is. desirable to eliminate one of the latter two elements. Further, the fiber-faced baffle sheet may be disposed internally of the pad body, at any desired location wherein the fiber surface of the baffle sheet will frictionally engage other fibrous material in the pad body.

.It will also be apparent that other modified forms of absorbent bandages, sanitary napkins and the like, and other materials may be used without departing from the principles of this invention. For example, while the baffle sheet 14 in Figure 1 is described as a plastic film having a fibrous web embedded therein, a fluid-repellant plastic sheet having a fibrous or other friction-producing covering which is bonded or otherwise secured in position on one or both sides of the sheet may be employed in a manner similar to sheet 14 so as to secure the advantages discussed above. Suchfi bflfil i i lus a d in l 4- wherein a fluid-repellant sheet 40 is bonded to a Web 42 of fibrous material by a series of adhesive spots 44 suitably spaced along the inner surface of one of the materials. As in the previous embodiment, the fibrous covering 42 may be of any form, a carded Web, a Woven or non-woven web, with the principal consideration being that it provide a frictional surface which is integral with the impervious baffle sheet 40 and provide a minimum of additional bulk to the completed pad. It will be apparent that, if desired, a fibrous web may also be applied to the opposite surface of the baflle sheet 40 to provide a frictional surface on both sides thereof. It is intended, of course, that the baffle sheet thus formed will be used in the manner discussed above with respect to Figure 1.

Still another modified form of the invention is illustrated in Figure 7, where the bulk of a fiber-faced bafiie sheet embodying the invention is further reduced by utilizing spaced-apart fibrous appliques 50 on a fluid repell ant film 52 to form a baffle 54. These fibrous spots may be bonded to the film 52 in any suitable manner, such as by the use of an adhesive or by embedding the fibers in the film in the manner illustrated in Figures 3 and 5. The presence of the fibrous spots 50 on the otherwise slippery film of material, which provides a fluidrepellant baffle for the fluids in the pad, provides means for frictionally engaging the overlying wrapper and/or side strips in the manner described above with respect to Figures 1 and 2.

Other modifications within the scope of the present invention will become apparent to those skilled in the art.

This application is a continuation of my co-pending application Serial No. 522,092, filed July 14, 1955 and now abandoned, entitled Sanitary Napkin.

I claim:

1. An absorbent pad comprising a body of fluid absorbent, fibrous material, a fluid resistant baffle sheet, and a fibrous wrapper disposed about said pad body and battle sheet, said baffle sheet comprising a web of fibers embedded in a thin plastic film, said bafile sheet being so disposed in said pad that frictional engagement is established between the fibrous surface of said baflle sheet and an adjacent fibrous surface in said pad thereby preventing relative sliding movement therebetween.

2. An absorbent pad comprising a body of fluid absorbent material, a fluid-resistant baflle sheet disposed on the outer surface of said body, said baffle sheet comprising a web of fibers bonded with a thin plastic film and disposed with the fiber-faced surface facing outwardly of said pad body, and a fibrous wrapper for said pad disposed about said pad and baflie sheet, whereby the frictional engagement between said wrapper and the fibrous surface of said baflie sheet maintains the latter in position on the pad.

3. An absorbent pad comprising a body of fluid absorbent material, a fluid-resistant baffle sheet disposed in the outer surface of said body, a fiber-faced surface portion provided for said baflie sheet by the bonding of fibers with said sheet, said baflie sheet being disposed with the fiber-faced portion thereof facing outwardly of the pad body, and a fibrous wrapper for said pad disposed about said pad body and baffle sheet, whereby the frictional engagement between said wrapper and the fibrous surface portion of said baffle sheet maintains the latter in position on the pad body.

4. An absorbent pad comprising a body of fluid-absorbent material, a fluid-resistant baflle sheet disposed on the outer surface of said body, a plurality of spaced-apart fibrous appliques bonded to the outwardly facing surface of said baflie sheet, a pair of fibrous side strips extending along the edges of said pad body and having longitudinally extending portions thereof disposed in overlying engagement with opposite edge portions of said baflle sheet a d W th a least one of said fibrous appliques thereon,

and a Wrapper of fibrous material folded about said pad body in overlying relation to said baffle sheet.

5. An absorbent pad comprising a. main body of fluid absorbent material, a fluid resistant baflle sheet disposed on the outer surface of said body, said baffle sheet comprising a web of fibers embedded in a thin plastic film and disposed with the smooth film side adjacent said pad body, and a pair of fibrous side strips extending along the edges of said pad body and having longitudinally extending portions thereof disposed in overlying engagement with opposite edge portions of said baflie sheet, whereby the engagement between said fibrous side strips and the fibrous surface of the baflle sheet maintains the latter in position relative to the pad body.

6. An absorbent pad including a body of fluid absorbent material having an outer covering of creped tissue, a fluid resistant baffle sheet comprising a sheet of creped tissue embedded in a thin plastic film and disposed in covering relation to a substantial portion of the pad, with the film side of said baflle sheet adjacent said pad body, a pair of side strips of creped tissue extending along the edges of said pad body and having longitudinally extending portions thereof disposed in overlying engagement with opposite edge portions of the tissue surface of said baffle sheet, and a wrapper of loosely woven fibrous material folded about said pad body in overlying relation to the crepe tissue surface of said bafile sheet.

7. An absorbent pad including a body of fluid absorbent material having an outer covering of creped wadding material, a fluid resistant baffle sheet comprising a thin film of plastic material and a web of loose creped fibrous material bonded together in superposed relation, said baffle sheet being disposed in substantially covering relation to one side of said pad body with said film facing said body, a pair of sidestrips of creped wadding extending along the edges of said body and having longitudinally extending portions thereof disposed in overlying engagement with opposite edge portions of the creped fibrous surface of said baifle sheet, and a wrapper of loosely woven fibrous material for said pad body which is folded in overlapping relation on the side including said baflie sheet, whereby the frictional engagement between said side strips and said loose creped web on said bafile sheet and betweensaid overlapping wrapper portions and said baffle sheet maintains the latter in position on said pad body.

8. An absorbent pad comprising an elongated main body of fluid absorbent material, a fluid resistant baflie sheet substantially covering one surface of said pad body, said baflle sheet comprising a loose, creped web of fibers embedded in a thin plastic film and disposed with the fibrous surface facing outwardly, said plastic film having a thickness within the range of from about 0.15 mil to 1.50 mils, and said creped web having a basis weight of between about 2.0 lbs. and 20.0 lbs. per standard ream of 2880 square feet before creping and a crepe ratio of from 1.0 to 2.3, a pair of creped, fibrous side strips extending along opposite edges of said pad body and disposed in overlying engagement with opposite edge portions of said cover sheet, and a gauze wrapper for said pad comprising a web of loosely woven fibers folded 6 lengthwise of said pad body and overlapped on said baflle sheet.

9. An absorbent pad comprising a body of fluid absorbent, fibrous material, and a fluid-repellant baffle sheet, said baffle sheet comprising a thin, fluid-repellant film disposed between a pair of fibrous sheets and secured thereto, with the composite baffle sheet disposed relative to said body of fibrous material so that frictional engagement is established between at least one of the fibrous surfaces of said baflle sheet and an adjacent surface of the fibrous material in said'body to prevent relative sliding movement therebetween.

10. An absorbent pad comprising a body of fluid absorbent material, fluid resistant baffle sheet, and a fluid permeable wrapper, said baflie sheet comprising a thin plastic film treated on at least one surface thereof so as to increase its-frictional resistance, said baffle sheet being disposed covering relations to a substantial portion of said body with a treated surface of the sheet facing outwardly of said pad body, and said wrapper being disposed about said pad body and baflle sheet, whereby frictional engagement is provided between said wrapper and said baflle sheet to maintain the latter in position in the pad.

11. An absorbent pad including a body of fluid absorbent material having an outer covering of creped tissue, a fluid-repellant balfie sheet comprising a thin plastic film having a fibrous web attached to opposite surfaces thereof, said baflle sheet being disposed on one side of said pad body in covering relation to a substantial portion thereof, a pair of side strips of creped tissue extending along the edges of said pad body with longitudinally extending portions disposed in overlying engagement with opposite edge portions of said baflle sheet, and a wrapper of fibrous material folded about said pad body in overlying relation to said baffle sheet, whereby the frictional engagement of the fibrous surface of said baflle sheet with said pad body, said side strips, and said wrapper maintains said baflie sheet in position relative to said pad body.

12. A sanitary napkin comprisinga body of fluid absorbent, fibrous material, and a fluid-repellant baflle sheet, said bafile sheet comprising a thin, fluid repellant film having a web of fibers bonded to opposite surfaces thereof, with the composite baflle sheet disposed relative to said body of fibrous material so that frictional engagement is established between at least one of the fibrous surfaces of said battle sheet and the fibrous material in said body to prevent relative sliding movement therebetween.

References Cited in the file of this: patent UNITED STATES PATENTS Great Britain 1938 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 52,896,621 July 28, 1959 Kenneth Harw'ood.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Celumn 3, line 21 for "m1" read m mil column 6, line 18, for "covering relation-s" r eed we in covering relation m Signed end sealed. this day of 1960,,

(SEAL) Attest:

KARL I1 0 AXLINE ROBERT C. WATSON Attesiting Ofiicer Commissioner of Patents

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