US2600576A - Sanitary napkin - Google Patents

Description

June 17, 1952 c. RlcKARD ET AL SANITARY NAPKIN 2 SHEETS-SHEET 1 Filed Aug. 4, 1950 Nrn AMA,

d. m W. J m e n fm June 17, v1952 c. l. RICKARD ET AL SANITARY NAPKIN zlsl-lEETs-SHEET 2 Filed Aug. 4, 1950 Patented June 17, 1952 SANITARY NAPKIN Charlotte I. Rickard and Kenneth J. Harwood,

Neenah, Wis., assignors to International Cellucotton Products Company, Chicago, Ill., a corporation of Delaware Application August 4, 1950, Serial No. 177,702

(Cl. 12S-290) Claims. 1

This invention relates to improvements in sanitary catamenial napkins and the principal .object of the invention may be said to be that of providing a sanitary napkin of greater eiliciency than those heretofore available.

Efficiency of a sanitary napkin as herein referred to, takes into account many factors and characteristics of the napkin, for example, (a) the absorption capacity of the napkin, (b) the absorption spreading characteristics thereof, (c) the tendency of the napkin to move from its proper place due to body movement and muscular action, (d) the weight and bulk of the napkin and its reaction to the pressures to which itis subjected when worn, and (e) comfort characteristics of the sanitary napkin when worn. Other characteristics and qualities may also have a bearingr on this matter of efficiency but those just referred to are probably the most important and the present invention is concerned with improvements which relate mainly to the aforesaid characteristics. e

In connection with the details of construction of a sanitary napkin to attain high efliciency, it is of course important to consider the practicability of the structure from a manufacturing viewpoint. Commercial considerations require that a construction be such that it may be massproduced at high speed by automatic machinery at very low cost.

The present invention aims to provide a sanitary napkin which embodies a more eilicient construction and which improved construction may be mass-produced at high speed by automatic machinery and at low cost as aforesaid.

Other objects and advantages of the invention will be understood by reference to the following specification and accompanying drawings wherein the invention is illustrated in several embodiments.

In the drawings, Figure 1 is a fragmentary perspective which embodies a longitudinal section through one form of a sanitary napkin embodying the invention;

Figure 2 is a view similar to Figure 1 but showing another form of construction;

Figure 3 is a perspective illustration of one component of the pad structure shown in Figure 2;

Figure 4 is a section on the line ll--4 of Figure 2;

`Figures 5, 6, 7 and 8 are side elevations of other forms of construction of a component of a sanitary napkin according to the present invention; Figure 9 is a perspective illustrating approxi- (original No. 1,857,854, May 10, 1932).

mately the condition to which the absorbent pad portion of the napkin is folded when worn; and

Figures 10 and 1l are sections, respectively, on the lines lll-I0 and II-II of Figure 9.

The sanitary napkin construction shown in Figure 1 comprises an absorbent pad body` or unit I enclosed in a wrapper of gauze 2 or other suitable material. Arrangement of the wrapper about the absorbent pad may be in accordance with conventional practice and is not illustrated in detail. In accordance with such conventional practice the wrapper has end extensions 3 and at the front and rear ends respectively of the absorbent pad body, these extensions being usually employed for attaching the napkin to a supportingl belt or to otherwise support the napkin when worn. k

The pad body l comprises top and bottom or outer face layers 5 and 6 of absorbent crepe tissue paper, these layers being of substantially like length and having their end portions pressurebonded together as indicated at 1 substantially in accordance with the teaching of United States Patent No. Re. 21,706 Glomstead, May 9, 1939 Inside layers 8 and 9, also of suitable absorbent material, are provided intermediate the layers 5 and 6.

vThe material employed in the layers 5, B, 8 and 9 may -be crepe tissue paper, preferably arranged `with the creping extending lengthwise of the layers. The layers 5 and '6 may advantageously consist of about ten plies of crepe tissue paper, the layer 8 of about ten plies and the layer 9 of about eight plies, the layer 9 being treated as taught in United States Patent No. 1,863,333 to Heitmeyer June 14, 1932, to form this layer into a so-called equalizer, i. e., a device having a capacity of accelerating the spread of fluid absorption lengthwise within the pad. Other suitable absorbent materials may be employed in the construction of any or all of these layers as will presently appear.

The layer 8 is of less length than the outer layers 5 and 6, being here shown as of about three-fourths the length of said outer layers. Said layer 8 has one end bonded to the front ends of the layers 5 and 6 by being extended between the end portions of the layer where they are compressed as indicated at 1. The other end of said layer 8 terminates as indicated at I0 at a considerable distance from the rear end Hof the, pad. The layer 9 which, as above indicated, is. preferably compressed along longitudinal zones'tofform aso-called equalizer is shorter than the layer 8.1and

CII.

portion is adapted to remain in a flat bodyhug-V Y ging condition when the napkin is worn. Similarly the rear end portionof the napkin is reduced in thickness to the combined thickness of only the outer layers and G as indicated at l2. The reduced rear end thickness indicated at I2 is more or less gradually increased tothe full thick-v ness of the main :pad body through the agency of the short rear end portion Baof the intermediate layer 8.

The described arrangement of pad layers results in a pad having its maximum thickness and absorption capacity in that quarter (indicated at I3` in Figure l) of the length of the napkin immediately in front of the middle of the pad part of the napkin between its front and rear ends.v

Another construction is shown in Figure 2 wherein the napkin embodies a pad Ill enclosed in a suitable gauze wrapper I5 having front and rear attachment tab extensions i6 and Il, `respectively.

The absorbent pad body i4 com-prises upper and lower or outer face layers IB and I3 lrespectively, each of which may consist of around ten plies of crepe tissue paper. Said outer plies are oflike length and have their ends pressure-bond-` ed together as indicated at 23.

Between the multi-ply tissue layers i8 and I9 therev is an absorbent filler structure which, in this instance, comprises upper and lower layers 2| and 22, respectively, and an intermediatelayer 23.

l'.iherupper layer 2l may consist of a layer 24 (see also Figure 3) of finely divided cellulose ber or so-called Huff on a supporting or backing sheet of crepeV tissue paper. The said fluff layer'2'4 has a thickness A for about one-half of its width and then tapers from about a mid-point of its with at B to a very thin or featheredge at C. The layer 22 may be similar to the layer 42i or it may be of substantially uniform thickness `from end to end as shown in Figure 2, being, however, constructed of a layer` of said uii material on a supporting or vcarrier sheet of crepevtissue or similar material. 'I'he'intermediate layer 23 may be formed of a layer of said fluff material between upper and lower connning sheets 26 and 2l, respectively',"i` crepe tissue paper or other similar material and this intermediate layer 23 may be made intoV a so-called equalizer element by pressure treatment according'to the teaching of the above mentioned Heitmeyer patent. As shown in Figure 4 the intermediate layer 23 is provided with longitudinally extending alternately arranged relatively compressed zones 23 and incompressed zones 29 as 'a result of said pressure treatment.`

A baiile sheet 33 may be positioned in the absorbent ller unit intermediate the equalizer 23 and the upper Vor lower layer 2l and 22, preferably the lower layerlas shown. Such baille sheet may consist of one or two (or more) plies of crepe tissue paper suitably treated to impart the de# sired degree of moisture-proofness thereto. It is preferable that such moisture-proofness be adequ'ate enable the baille-"sheet towithstand' uid penetration until a substantial volume of uid has been received in the pad above the baiiie sheet and until the fluid pressure is built up to a point where it can force the fluid through the baille sheet. The iiui material employed in the layers 2|, 22 and 23 and the tissue carrying or supporting plies associated with said layers are preferably of a highly absorbentcharacter so that they will readily absorb fluid delivered thereto.

In the construction in Figures 2 to 4 inclusive, the layer 2| with its tapering thickness portion imparts to the pad M tapering thickness characteristics similar torthose of the pad I shown in Figur-el. In-the. Figure 2 arrangement the quartei-portion 3L ofthe over-all pad length immediately in front ofV the center of the pad embodies the maximum thickness of the pad body portion and provides the maximum absorption capacity portion of said pad.

Tapered thickness absorbent pads may be made by employing an absorbent section suohas represented in Figure 5 which is made from-a web. of the character represented in Figure 6. In Figure 6 a layer 32 of ui is deposited on a crepe tissue or similar carrying sheet 33. The layer 32 has a centrally located portion. of uniform. .thickness D and end portions which taperV from the. thickness D to featheror near feather edges as. shown. Such a web. is folded on itself at about its mid-point indicated at-34, the carrying sheet 33 being on theo-utside, thereby to form the folded structure .shown in Figurer. The folded,.tapered pad element shown in kFigure 5 has `a -main portion having two thicknesses D in relatively superposed relation to, each other and two tapered end portions in relatively superposed relation to thereby provide a pad havingl about one-half its length of uniform thicknesscorresponding to two times D and the otherhalf of its thickness tapering from said main thickness to a thin edge 35.

An absorbent insert such as shownin Figures 5 and 6 may be substituted for the-multiplelayer insert between the outer layers IBVandVIS inthe Figure 2 constructi011.orif desired, the entire absorbent pad 4may be representedl by the structure shown in Figure 5 which, in that case would be made of appropriate lengthv to correspond to the full desired pad length, `and Acovered with a suitable wrappernsuch as the wrappers 2 and l5 of Figures l and 2 respectively.

The form ofpad component shown in Figure? comprises a wrapper 36 of crepe tissue paper or other suitable material which is initially spread out in flat web form and on which is deposited a layer 3l of nuff, the layer being deposited so as to'have a uniform thickness over about one-,half the width of the layer "andgatapering thickness as shown over the remaining portion of the width of the layer. A web Aof equalizer material 38 (or a `baile element) `is next deposited on top of the ufflayer`r 31 if suchf equalizer or baiiiejare desired, and another fluff layer 39 Y,similar to the fluit layer 3l is deposited on the equalizer. The marginal portionsv 36ay and SSb'ofthe wrapper sheet 36 are then folded over the iluilv layer V39 and into mutually lapping -relationship as shown to confine said uffmaterial.

Another tapered form of pad construction can be attained as Vshown in Figure S where a series of layers 40, 4l, 42 and 43 of progressively increasing length are assembled together to lform a more or less step-tapered pad. Thelayers-may be vmade of superposed plies of crepe tissue paper or of yiiuifmaterial with or without backing sheets, and either equalizer or baffle strips or both, may be incorporated at any desired location in such a step-tapered structure.

The pad body structures represented in Figures '7 and 8 may be used in the lsame manner set forth above in respect "of the structure shown in Figure 5. Y

Pad body material having the cross-sectional shape shown in Figures 5, 7 and 8 may be made in long lengths and rolled up into supply rolls for subsequent delivery to pad forming machines which are equipped with instrumentalities to cut of'l successive end portions of the required width to form the desired pad units. A typical machine of this character is represented in United States Patent No. 2,262,275 Fourness and Greiner, November 11, 1941. y

The various elements or layers ofthe pad body are of substantiallyv constant thickness from side to side of the pad in each elementary unit of length thereof as shown in Fig. 3, said thickness varying however, from end to end, in some of the layers as already explained. Pad elements of such uniform side to side thickness are obtained when vthese elements are cut one byone from the end of a long supply strip of the material as above explained, the said supplfy strip being formed with transverse cross section corresponding to the desired longitudinal sectional form of the element.

Absorbent sanitary napkin pads have been made in various laminated arrangements in which certain layers terminate short of the ends of the pad body so as to provide end portions of reduced thickness. Pads so made have been symmetrical in form and the absorbent capacity thereof has been substantially uniform throughout a major portion of the length of the pads, such portion being centered between the ends of the pads.

Conventional sanitary napkins of this general character have been evolved over a period of about the last thirty-five years, beginning. with an all-crepe tissue paper pad of rectangular pad and uniform thickness from end to end. During these years of development, one of the persistent complaints has been that the absorbent pads have a tendency to wet or strike through from the body side to the outside. Absorbed fluid usually penetrates the entire pad thickness in a zone intermediate the pad ends and usually,

nearer to one end of the pad than to the other. This absorption tends to spread lengthwise of the pad from the zone of application. Of course the spread of absorption depends to a considerable extent upon the amount of fluid delivered to the napkin and the length of time that the napkin is worn. Due to the discomfort experienced when a napkin becomes very wet the tendency is to dispose of the napkin long before a major portion of'its absorptive capacity has been used up. This obviously reflects considerable inefficiency in the conventional pad structures.

When a sanitary napkin is applied it is normallyfolded lengthwise approximately as represented in Figure 9 where the front end of the pad is represented at 44 and the rear end at 45; intermediate the front and rear ends, the pad is folded longitudinally upon itself approximately as illustrated and this longitudinally folded portion is subjected to considerable compressive force between the legs of the wearer, whereby the normal thickness of the folded structure is reduced from something about as represented by the dotted line showing at 46 (Figure 10) to the fun une showing at 4s. `with the conventi'entiV uniform thickness pads this compression tends to increase the capillary ow of fluid toward the rear end of the pad and when the wearer has occasion to sit down, there is necessarily a tendency to further compress the pad material andv to express some of the absorbed fluid to the out-A side of the pad. The resulting adverse effects on the comfort characteristics of the napkin are self-evident.

This uniform cross-section of conventional pads also readily permits the displacement of the pad in a longitudinal direction unless the attachment tabs have been pulled up soy tightas to thereby create their own discomfort.

The described improved. construction withv a tapered thickness rear portion provides maximum absorption capacity in the area of the padV This reduction in bulk in the rearward portion ofv the pad serves to prevent the application of a significant portion of the capillary producing compression on said rearward portion and also to prevent the application of fluid expressing pressure thereon as often occurs with conventional uniform thickness pads as above explained. The forward thicker portion, being subjected to the usual capillary increasing compression will, however, effectively take up and hold the fluid reaching the same. By employing an equalizer strip such as the strip 23-in Figures 2 and 4 in the pad body rearward absorption may be promoted interiorly of the pad and permits extended Wear of the pad if desired until even its rear portions are quite moist. If preferred, the equalizer strip may be terminated somewhat short of the rear end of the intermediate plies to accordingly control the rearward spread of fluid absorption.

The absorption capacity of the described tapered thickness pad structure is substantially equal in a practical sense to the absorption capacity of a conventional uniform thickness pad having a bulk of absorption material which i's greater than that of thetapered thickness pad by an amount approximately equal to that which has been'eliminated from the rear portions of the described tapered structures to form the taper. Hence, efficiency of the described tapered:

structure is in fact substantially higher.' than the absorbing efficiency of the conventional unform thickness pad.

Because of the reduced thickness of the rear portion of the pad, the pad is somewhat more flexible lengthwise and therefore may be more easily centered on the body and caused to conform to the anatomy, thereby improving the comfort characteristic of the napkin.

The longitudinally tapering or wedge shape of. the napkin when folded for application'to lthe body, provides a front portion whichu is transversely enlarged, as from side 48 to side 459V in Figure 10, as compared with the dimension in a" corresponding direction of a rearwardportion as represented in Fig. 1l. This transverse front enlargement tends to anchor the pad against rearward displacement incident to body and' muscular` activity so that the improved pad has a ypronounced tendency to remain in place'. this being animportant improvement overtheprior

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