US2073410A - Absorbent package or pad - Google Patents

Description

March 9, 1937. E B, THOMAS I 2,073,410

ABsoRBENT PACKAGE 0R PAD Original Filed Deo. 26, 1925 Patented Mar. 9, 1937 UNITED STATES- P'A'rlazN'l ori-*ics Reled for abandoned application Serial No.

December 26,'1925. This applicatlo octqber s, 1934, serial No. 141,594

sclai'ms. (ci. 12s-29o) My invention relates to packages orv pads of absorbent material, of general use for absorptive purposes but particularly adapted for use in sanitary napkins. More particularly my invention aims to provide an improved and less expensive .material and article of the class described, in-

cluding means for controlling or directing its absorptive action. This application is a re-iiling, with identical disclosure of the means ofl my inventio'n, of my previous application S. N. 77,786,

filed December 26, 1925.

It has heretofore been proposed to employ in forming absorptive pads a relatively large plurality of layers er webs of extremely tenuous and `l5 film-like wood cellulose material, generally some thirty-five to forty of such webs being superposed. -Said webs are each separately formed, and because of their extreme thinness require slow and careful handling during the process of manufacture and in forming the pads. They cannot be run rapidly through the rollers, drums and the like necessarily employed in the production of the same. The expense of manufacture is further increased by the fact that special machinery as or special and costly adaptation of the usual pulp.

handling machinery is required.

For the purpose of decreasingmanufacturing costs, and at the same time providing an improved product, Qin accordance with my present 80 invention, I employ a less number of layers or webs of wood cellulose which, while thin as compared with the thickness of the absorbent pad as a who1e,.have suillcient substance and are of such consistency as to be susceptible loi rapid handling and by machinery of the standard form generally used in manufacturing from wood pulp.

In the drawing illustrating embodiments of certain forms of my inventionz-v Fig. I is a vertical section showing a layer or 0 web of thecellulose material in the form in which it comes from the web-forming machinery;

Fig. 2 is an expanded view, in perspective, of a plural-layer absorbent pad embodying one form of my invention;

Fig. 3 is a similar view, showing the pad assembled, portions of the upper layers being broken away:

Fig. 4 is a corresponding 'view showing a pad 5o with modified form of absorption controllingmeans;

Fig. 5 is a perspective view of layers of absorptive material illustrating another arrangement Fig. 6 is a view similar to Fig. 5 showing a further modification of absorption controlling means embodying my invention.

Referring now more particularly to the drawing, I have shown at the left in Fig. 1 a web or 5 layer I of the wood cellulose material as it comes from the drums and rollers of the web-formingV machinery. At that ktime the web has substantially the consistency, form, and surface characteristics of ordinary blotting paper, and is pref- .10 erably of about the thickness of that product. It may be formed by means of the usual machinery employed in producing blotting paper and the like, without necessitating any rearrangement or costly change in such machinery, thus making it l5 possible to use the same machines and to shift readily from the manufacture of the present product to `another without additional expense. 'Ihe cellulosic material of which said webs are formed is preferably wood cellulose of the so- 2o called "alpha fibre type, consisting of a soft wood pulp, such as pine, from which practically all traces of pitch and tar have been removed. f

So far as I am aware webs of wood cellulose of said form and character have not heretofore been employed or suggested for use in connection with absorptive packages for sanitary napkins or thelike, and in the form so far described are wholly unsuited for such use because of their stiffness,

harshness, surface matting of the ilbres, etc.

As lillustrated in Fig. 1, the webs in their stiff, libre-matted condition in which they come from the web-forming machinery, as indicated at l, are subjected to a softening,'fluiing, napping,

crumpling, or other like action spreading and 35 separating the fibers, on both faces of the web.

different speeds so as to subject the webs to a '45 .surface matting of the abres. Both m appearance and to the touch the webs vthus treated so closely resemble natural short-staple absorbent cotton as to -be scarcely distinguishable from it. .55

In a package or pad formed ofthe material as described the natural absorptive vaction is substantially the same in all directions in the plane of the web, and is .somewhat greater'in that plane than in the direction through the pad.

For vsome purposes this is wholly desirable, but in 1 a pad for use in a sanitary napkin an objection arises which, unless remedied, would tend to outweigh the numerous advantages already mentioned. A

In a sanitary napkin the absorbent pad is' somewhat elongated, having a length preferably from two to three times the width of the pad.

Equal rate of absorption in all directions in the plane of the webs is advantageous, even in this case upto a certain point, since a greater lateral extent of the pad is brought into use, as compared for example with elongated .pads formed of a greater number of extremely thin webs, previously referred to, having a longitudinal grain resulting from necessary craping or the like and in which the absorption is much' greater longitu dinally of the pad and too limited in the lateral direction. But thisadvantage extends only to a certain '35 point, namely, where the maximum desired lateral spread is reached. Beyond that* point the ability of the pad to absorb equally rapidly in all directions in the plane of the webs becomes a disadvantage in an elongated pad, since the uid may spread by absorption to the outer side edges of the pad, with undesirable results, before the desired longitudinal extent -of the pad'has come into action.

My invention therefore includes a method and means for controlling or directing the absorptive action, and whereby the absorption may be made to take place laterally of the pad to the desired extent but not beyond, and also at a greater rate downwardly in the direction through the pad and over the entire available area ofthe pad rather than locally only.

For this purpose, as clearly seen in Figs. 2 and 3, one or more of the webs, starting at the upper face of the pad, are provided with one or more cuts, slits, or like formations 'Lrdesirably substantially parallel when a plurality is employed, and extending in a direction approximately perpendicular to that direction in the plane of the web in which it is desired to decrease the abw sorptive eiliciency. Said cuts or .slits preferably are each substantially continuous, as in Figs. 2 and 3,'- and in Fig. 6, in which latter each such formation comprises a series of shorter'cuts or slits 'I'. Each such formation has an overall length approximately. that of the area over which absorption is desired, but not exceeding such length. Desirably they terminate sumciently short of the end edges to preserve the structural strength oi the pad.

70 By means of' said slit-like formations the lateral absorption in the slitted web is impeded or wholly checked. The absorptive action is di' rected and controlled since the uid will not readily ,cross from one slit edge to the opposite 75 one, `even though slitted edges are in contact or thereof.

fthe web and into the next lower web or webs.

Preferably the number and arrangement of the slits are such that the resultant absorption will 5 be distributed evenly over the entire available area, that is, the area which it is permissible or desirable to employ. The .proper longitudinal distribution will )have taken place in substantially the same time as the less extensive and re- 10 tarded lateral distribution, while the down-absorption simultaneously is materially increased and more evenly distributed.

In Figs. 2 and 3 I have illustrated four slits in the upper or rst web, which, being the first` to 15 receive the iiuids, requires the greatest direction or control of its absorptive action. The number of slits may be -increased or decreased according to different conditions. Also in the succeeding layers or webs the number of slits may be progres- 20 sively decreased or otherwise varied toward the bottom of the pad. By way of example, in said Figs. 2 and 3, I have shown three slits in the second web, two in the third, three in the fourth. two in the fth, and one in the sixth or next to 26 the bottom web, and none in the last or bottom web. Itwill be understood that the number of layers or webs may also be varied.

If a less increaseof the downward absorptivev action is desired, the slitsin succeeding webs may 30 be diiferently spaced apart, staggered or otherwise arranged so as not to come one directly beneath or above another, as in said Figs. 2 and 3; or if a greater down absorption and somewhat less limited lateral absorption is desirable )an 35 arrangement similar to that of Fig. 4 maybe employed, wherein I have shown four slits in each of the first two webs, and in coinciding positions, two slits in each of the two succeeding A webs, also in coinciding position but diifering 40 from the position of the slits in the iirst webs, the remaining webs being unslitted. 'Ihe arrangement and number of slits, and the number of webs slitted, may thus be widely varied in ac-I cordance with the circumstances and with the 45 results desired.

In some instances it has been found useful to arrange the slits somewhat on the bias, as shown in Fig. 5, the slits 1 being inclined at any desired angle to the longitudinal axis of the pad, and in 50' either direction, preferably not exceeding 45, so

'that their general direction remains lengthwise the pad. Y

As above pointed out the described method an structure result'not only in properly limiting the 55 lateral absorption 'but also in increasingthe down absorption, which latter is made to occur not locally merely but over the entire available area of the pad. Any possible leakage at the bottom of the pad is desirably prevented by suitable moisture-proofing means l, preferably such as disclosed in my Patent No. 1,564,498, dated December 8, 1925, and thev Reissue No. 16,603

My invention is not limited to the particular c5 embodiments thereof shown and described by wayof illustration, its scope being set forth in the appended claims.

I claim:

1. An absorbent pad particularly adapted for use in a sanitary napkin, comprising a plurality of superposed webs of cellulose material relatively thick as compared with a tenuous iilm and wherein the absorptive rate is normally ,substan-i tiallyequal inalldirectionsintheplaneofaweb,

certain of saidwebs having one or more substantially continuous slit-like formations extending in a general direction approximately at right angles to the direction in which it isA desired to limit the rate of absorption, and of a length less than the dimension of the pad in the direction of'their extent, each web so formed having a peripherally continuous and non-slitted marginal portion integrally enclosing the same.

2. An absorbent pad particularly adapted for use in a sanitary napkin, comprising a generally elongated. attened pad oi absorbent cellulosic material, the pad being formed of a plurality of relatively superposed sheets of said material and tion in the pad to` be elongated longitudinally o! the pad from a localized area of uid application disposed more or less centrally of the pad. 3. in absorbent pad particularly adapted for use in a sanitary napkin, comprising a generally elongated, flattened pad of absorbent cellulosic material, lthe pad being formed of a plurality of relatively superposed sheets of said material, said pad having a: web of sheet material disposed inftermediate its thickness and providedwith la slit-i like iormation extending generally longitudinally o! the pad, said slit-like formation serving to cause the area of absorption in the pad to be elongated longitudinally of the pad from a localized area of iluidapplicationl disposed more or less centrally ofthe pad. vERROLD B. THOMAS;

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