CA1186452A - Moisture absorbent pad - Google Patents

Abstract

GEORGE BERNARD FOWLER
MOISTURE ABSORBENT PAD

ABSTRACT OF THE DISCLOSURE

A diffuser layer is interposed between layers of moisture absorbent material situated within a cover sheet. The diffuser layer comprises one or more tissue layers, each having a plurality of parallel corrugations to disperse moisture by capillary action. A
compression seal is situated in the cover sheet separating two pad parts. The compression seal comprises first and second crimps, spaced by a section of the cover sheet. The ends of the pad parts are also sealed by crimping. The absorbent material is wood pulp impregnated with a starch polymer or an acrylic-based polymer to increase the absorbency thereof. An agent may be included in the pulp to prevent the biological degradation of urine. Substances may also be Included in the pulp for absorbing volatile nitrogenous compounds and odors. In addition, a moisture or chemical sensitive indicator strip may be situated on the cover sheet.

Description

MOISTURE ABSORBENT PAD HUM-?

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The present ~nYention relal:es to molsture absorbent pads and, more particularly, .to ~mprovements in the construction of Inol sture absorbl ng pads to make same absorb more effic~ently, more easily insertable into a pouch desiyned to hold salne, and to certain substances desiyned for u5e there~n to prevent odsrs and irritat~on caused by urine.
- Mo~ s l;ure absorbent pads of the typP
~o whlch the present inven~ion relates are primar~ly designed for absorbing ur~ne and ~ .r;~, ~1~3G9c5Z

are, thus, use~ul as incont~nence pads7 bed pads~ or disposable diapers designed for use by ~nfants. Although the moisture absorbent pad can be used for a number of different applications~ the pads to which the present ~nvention relates are primarily designed for use as incontinence pads in conjunotion with a garment, such as a brieF; having a pouch designed to receive the pad therein. For this reason, the present invention will be descr1bed in conjunction with this type of pad. However, it is to be appreciated that the present invention is not limited to incontinence pads alone~ but has w~der-spread appl~cation and, therefore, referencesto incontinence pads in the specification should not be considered to be a limitation on the inYention.
It has long been recognized ~hat ~he full absorbenk capac~ty oF conventional moisture absorbent pads ~ rarely ut~lized because the dlstribu~ion of l~quid throughout the pad is usually.such that the liquid ~grates to the edges of the pad more quickly ~n certain dlrections than other directions.
Var~ous arrangements have been proposed to nl~n~mize this distribution imbalanoe by - util~zing such expedients as barr~ers o~
reduced permeabi 1 i ty or 1 ayers affordl ng a preferential direction for liquid spread.
However, none o~ these proposed solutions are entirely acceptable for reasons of performance, cast or production difficulties.
Incontinence pads, designed for use w~th incontinence garments such as pants or the like, are normally removable from the garment so that the used pad can be disposed of and the garment reused. For this purpose9 the tO gar~ent is provided with a pouch designed to recei~e the pad therein. Because such garments are often used by elderly or ill ~ndividuals, the ease with which the pad can be inserted into the garment is important.
It is there~ore desirable to construct the pad ~n such a manner as to facilitate lnsertion into the pouch of a garment, eith~r by-the wearer or, in the case of the ill or senile, by the person carin~ for the wearer.
Ease of removability 1s also tmportant, but is additisnally complicated because the pad is normally moisture lade.n when lt is ready to be removed. It is necessary ~or the pad to have sufficient strength so as ~5 not to disintegrate as it is being pulled ~rom ~he garment. In addition~ ~t is d~stasteful for the individual removing th2 pad to ha~e his hand com in contact with the urine saturated portions of the pad. It is 7:

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therefore desirable to construct the pad in such a manner that lt has sufficient structural integrity and can be removed without ooming in contact with the urine-laden portions~
Si nce the moisture absorbent pads are often worn for extended per;ods of tîme after urine has been absorbed therein~ odors caused by the urine can beco~e a problem.
In addition~ persons with urinury tract in~ect~ons may excrete volatile nitrogenous compounds in the urine. Such compounds would normally escape from the pad, causing an additional odor. It is therefore desirable to include, within the pad, compounds which either neutralize or mask odors.
In many instances~ such as when the pads are used by inf~nts or senile indiv~duals, lt ls impossible for the person carlng for the ~nd~viduai to ascertain whether or not the pad has absorbed urine without touching same to see ~f it is moist, wh~ch process could be cons~dered to be disayreeable. For th~s reason, ~t would be desirable to incorporate a mo~sture indicator on a visible portion of ~he pad such that one could tell at a glance whether the pad need be removed or not Moreover, in certain applications, it is desirable to inGorporate on the pad a means for visua]ly indicating the presenee or absenee of eertain chemieals in the urine. For instance, a test strip of the type which diabe-tics utilize to test for the presence of sugar could be incorporated on the pad.
It is a further objeet of the present invention -to provide a moisture absorbent pad whieh may be removed without eoming in eontaet with the moist-~re laden portions thereof.
The invention provides a pad of the type adapted to be situated in an ineontinenee garment or the like, said pacl eompris-ing first and seeond moisture absorbent parts and means forflexibly connecting said parts end-to-end, said conneetlng means being adapted to permit alignment of the parts in substantially faee-to-faee relation and eomprising a substantially non-moisture absorbent graspable portion, said portion being aecessible when said parts are in face-to-face relation and adapted to facilita-te removal of the pad frorn a garment without sllbs-tantial contact with said moisture absorbent parts.
The present invention relates to a moisture absorben-t pad, as described in detail in the foll.owing specification, and recited in the annexed claims, -taken together with the accompanying draw-ings, wherein li.ke numeral.s refer to like parts and in which:

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Fig. 1 is a part1al cu~-away plan view of the pad of the present invention, show~ng the internal construction thereofg Fig. 2 is a cross sectional v~ew, taken along line 2-2 of Fig. l;
F~g. 3 is a fragmentary cross-sectional view illustrat~ng the form of the rollers used ~n the production of the diffuser layer, Fi gs . 4A and 4B are idealized diagrams illustrating ~he formation and struct~re o~ the diffuser layer, respecti~ely;
Fig~ ~ is a plan view of a two-part absorbent pad, in accordance with the present invention; and, Fig. 6 is a side view of the two-part pad illustrated in Fig. 5.

The first aspect of the present ~nvention relates to the construct10n of the 20 pad whi ch permi ts uni ~ornl ~i stri buti on of the 1 i qui d throughout the pad so as to more efficiently ut~l~ze sa~e,~thereby permitt~ny the absorpti on of a greater amount of l ~ qui d .
In accordance with th~s aspect sf the inventlon, the pad includes~ between layers of absorbent material, at least one diffuser layer comprising one or a plurality of sheets o~ tissue which have been corrugated by passing same between a pair of matching grooved rollers ~o form .. ~, ,.~

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corrugations having a pitch of the order of one millimeter, with the density of the tissue varying at least 3Q% across the width of each corrugation.
Such corrugated tissue is simple to manufacture, can be handled quite easily by conventional mach~nery on which absorbent pads are produced; and provides a strong wicking or capillary action longitudinally of the corrugations. Thus, if the corrugations are arranged longitudinally in an elongated rectangular pad~ the rate of diffusion of l~quid ~rom the center of the pad towards its longitudinal extremities ls greatly enhancéd, with the result that in the time it ~akes liquid to spread to the lateral edges of the pad, the liq~id will spread much further in the longi-tudinal direction 9 than would be the case without the dl~fuser layer. In this way~ a gr ater proportion o~ the absorbent material ~s ef~ectively utilized ~n absorbing the liquid be~ore the pad becomes unacceptable to the user.
The d~ffuser layer can be manufactured

2~ by drawing off crepe tlssue from a roll of stock and passing it between grouved rollers which ~orm longitudinal corrugations 1n the tissue and the corrugated tlssue can then be fed directly - betwecn two webs of absorbent material in a continuous operation.

o ,~2 Most conveniently, in practice, the material which is fed between the rollers comprises multi-ply9 creped tissue so that the d~ffuser layer thus produced consists of a plurality of piles or sheets in which the corrugations are fully in register. However~
a single-ply of creped tissue, of relatively greater width, may be passed between such rollers and, thereafter, ~olded upon itself 10 several ti~es so as to fnrm a multi-ply layer ~n which the corrugations ~n individual sheets are not exactly in registratisn w1th one another.
In passing the tissue between thé
15 corrugated rollers, the tissue ~s stretched laterally at a series of localized positions across ~ts width, with the result that the lateral coherence of the t~ssue is substan~ially d~srupted and the result~ng product consists 20 o~ a pluralit~y of longitudlnally extending zones o~ differ~ng density. In ~ccordance wtth the invention 9 the density variation is at least 30% and, preferably, approximately 50%.
By this roll~ng/stretch~ng process~
25 the lateral st:rength of the t~ssue is also reduced by a similar Pac~or, as compared wi~h the untreated tissue, because the zones of re,tluced density a~ord 1 ines of weakness and, ulti~ately, if the degree of stretching is 3û

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sufFlcient~ the orig~nal~ coherent tissue is e~fectively reduced to a number of strands wh~ch barely cohere to one another. Thus, the ~ diffuser layer formed ln this way not only 5 ~s h~ghly efficient 1 n promoting preferential diffusion of liquid in a desired direction, it ~s also readily disruptable so that the use of this layer does not impede disposal of the used pad by toilet flushing.
Figures 1 through 4 illustrate this aspect of the invention. As shown in F~gs. 1 and 29 a typical absorbent pad 10 includes a non-woven outer cover 11 made of rayon or other similar fabric, and two layers lZ and 13 of suitable absorbent material such as flocked wood pulp or the like. In order to increase ~ts absorbéncy, the absorbent mater~al whlch compr~ses layers 12 and 13 may be impregnated with a starch polymer or an acrylio based polymer.
Layers 12 and 13 of absorbent material are separated by a diffuser layer 14. Diffuser layer 14 oomprises one or a plurallty of sheets of creped tissue which has been corrugated by passage be~ween a pa~r of matching rollers. The number of sheets may typically be between four and eight, although greater or smaller numbers may be ut~lized as appropriate ~or different types of pads.

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Likew~se, although the illustrated embodiment includes a single dif~user layer 14 between two absorbent layers 12 and 13~ the number of d~ffuser layers and absorbent layers may be varied, as necessary.
Fig. 3 illustrates a pair of matching rollers 15 and 16 formed with circumferentially extending grooves 17 and 18 which preferably have a pitch of approximately one ~illimeter. However, the pitch of the grooYes may vary between about 0.5 millimeten and 2 millimeters, and still function acceptably.
In addition, the grooves are provlded with a peak-to-trough depth of a dimensicn which is sim~lar to the pitoh thereof.
As t~le creped tissue is drawn betwe~n the rollers~ it is gr1pped and somewhat compressed at the point 1ndicated by the arrows l9 in Fig. 4A between the troughs of one ZO roller and the peaks of the other. The t~ssue ls~ thus9 stretched as indicated by the double-headed arrcws 20 between the polnts at wh~ch it is gripped. This is because ~he dlstance between the peaks Qf the grooves, as measured along the line 21 following the surface o~ the roller, exceeds ~he ~rans~erse spacing between the peaks as ~easured in the ax~al dire~t~onO

, ,~-Thus) as seen in Flg. 4B9 the multi-ply creped tissue mater~al is slightly compressed ~n a plurality of longitudinally extending zones 22 where it is gripped between the rollers and simultaneously stretched in the inter-mediate zones 23. The corrugations are so d~mensioned that the densi ty of the material ~n zones 23 is at least 30% less than in the zones 22 and, preferably, 50% less or thereabout.
In this way, the lateral cohesion of the cr~ped t~ssue layer is reduced by a similar factor, as compared with the untr~ated ti ssue .
The corrugated material provides a strong capillary effect in the longitudinal direction, but the zones of weakness 23 serve to reskrict the qwant~ty of liquid which flows ~n the transverse direct10n. Thus, the multi-ply corrugated crepe tissue, in accordance w~th the present invention7 forms a v~ry effic~ent dlf~user layer which promotes distr~bution of i~quid in the lengthwise direction and~ ye~, i~ can be manu~actured simply and eoonomioally Prom reliably available materlals, without requiring expensive or oomplicated equipment.
A seccnd aspect of the p~esent ~nvention is illustrated in Figs 5 and 6, which show a plan view of a moisture absorbent pad - wh~ch inoludes a cover sheet 11 and first and second spaced moisture absorbent parts 30~ 320 ., ~
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~8 ~c~2, Parts 30 and 32 are operably connected by means of a compression seal 9 generally designated 34O Seal 34 comprises a pair of hard or solid crimps 36, 38 which have a portion 40 of the 5 cover sheet interposed therebetween so as to ~orm a flexible joint.
At the non-connected ends of parts ~0 and 32 are situated additional hard or solid crimps 425 44, respectivel~O Each of the crimps 36, 38, 42 and 44 preferably comprise two rows, each containing a plurality of openings separated by aggregated material so as ~o ~orm a relatively rig;d crimp.
An incontinenee garment is provided with an internal pouch designed to receive a pad therein. The central seal 34 permits the pad to be folded along cover material 40 between central sr~mps 36 and 38 such that part 30 and par~ 32 are substant~ally in ~ace-to-face relationsh~p, if a double layer 1s deslred. Holding the pad by the central seal 34, jnsert~on of the double-strength pad into the pouch is facilitat2d~ After the pad has been used and is th~s moisture 7aden9 the pad can be extracted ~rom the pouch - by grabbing the central seal (which ls no~
mo~sture laden) and pulling ~utwardly. Since the seal is not mo1sture absorbent, grasping the pad in this manner assures tha~ the individual's hands will not come in contact ., i2 ~. /~
f ~r w~th the molsture-laden port~ons of the pad.
The pad can be used ~n a single layer in a similar manner simply by severing cover sheet 11 at 40 to create two separate pads, or both pad parts can be used in the unfolded state, so as to cover a greater area, by manipulating the end crimps 42 or 449 as described.
It should also be appreciated that the crimp structure illustrated in Figs. 5 and 6 also substantially enhances the structural strength of the pad, thereby preventing deterioration thereof when same is saturated by liquid. It should also be noted that parts 30 and 32 may contain flocked wood pulp impregnated w~th starch polymer or acrylic based polymers in order to increase the absorbency thereof. Stitl further, a d~ffuser layer, as described above, may be ut~lized ~n each of the parts 30 and 32 to enhance the uniformity u~ distribution of the liquld throughout same and~ therefore, increase the overall absorbency thereof. In this case, the Gurrugations are situated substantially perpendicul~r to the central seal 34 In xccordance with another aspect o~ the present invention, the flocked wood pulp absorbent material may have added thereta any one of a number of known bacterial static a~ents for preventing the biologioal degradat10n .~ .' . , !:

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~-8 of urine. Such agents prevent the growth of bacter~a of the species b. ammoniagenes and, therefore; prevent the formation of ammonia and amines by the biological degradation of urea~ creatine and creatinine.
In addition~ the use of a weak ac1d9 which ls solid in its normal state, as an additive to the moisture absorbent makerial will prevent any volatile nitrogenous compounds from escaping, if they are present in the excreted urine) due to a urinary tract ~nfection. Examples of acîds which may be useful for this purpose are borlc and cltric acids.
Moreover, certain well known deodorizlng agents1 urine neutralizing agents or odor masking agents can be used in order to prevent odors from emanating fro~ the pad.
Such agents may conveniently be situated in the moisture absorbent mater~al.
F1g. ~ shows a moisture~sensitive 1ndieator means in the form o~ a strip o~
material 50 situated along the center line of the cover material 11 of the pad 30, 32. The chemicals on the strip are designed so as to . change co10r-indicating that the pad has absorbed moisture Such a strip is particularly - useful when the pads are utilized by infants or

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senile indivlduals and permits one to ascertai n the state of the pad without the necessity of touching same.
It is also possib1e to replace the moisture sensitive indicator strip 50 with a chemical test strip9 such as is commonly used to test ~or the presence o~ sugar ~n urine by diabetics. The use of such a str~p will automatically alert the user to the presence of any unusual levels of chemicals in the urine.
It will now be appreciated that the present invention relates to a moisture absorbing pad which utili2es a diffuser layer within the mo~sture absorbent material to uniformly dis~ribute moisture throughout, thereby increasing the overall absorbency of the pad.
In addition, certain polymers can be added to the moisture absorbent ~aterial to make same more absorbent. Further, the present invent10n relates to a pad structure which oompr~ses two parts flexibly connected together by a central double rrimp to enhance the structural rigidity of the pad and to facilitate insertion thereQf lnto a pouch. Other aspects of the invention relate to the use of certain ohemioals in the moisture absorbent material to prevent the growth of bacteria, prevent the esoape of - volatlle nitrogenous compounds~ neutralize or mask odor. Indicator strips may also be used on the cover sheets.

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While only a limited number o~
preferred embodiments of the present invention have been disclosed herein for purposes of illustration, it is obvious that many 5 variations and modifications could be made thereto. It is intended to cover all o~ these variations and modifications which fall wi~hin the scope of the present inventiQn, as defined by the following claims:
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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A pad of the type adapted to be situated in an incontinence garment or the like, said pad comprising first and second moisture absorbent parts and means for flexibly connecting said parts end-to-end, said connecting means being adapted to permit alignment of the parts in substantially face-to-face relation and comprising a substantially non-moisture absorbent graspable portion, said portion being accessible when said parts are in face-to-face relation and adapted to facilitate removal of the pad from a garment without substantial contact with said moisture absorbent parts.

2. The pad of claim 1, wherein said connecting means comprises first and second spaced crimps forming one end of each of said first and second parts and wherein said graspable portion is situated between said crimps.

3. The pad of claim 1, wherein said connecting means comprises a compression seal.

4. The pad of claim 1, wherein said pad further comprises a cover sheet into which said parts are situated in spaced relation, and wherein the portion of said cover sheet between said parts forms said connecting means.

5. The pad of claim 4, further comprising crimps in said cover sheet at the non-connected ends of said parts.

6. The pad of claim 1, wherein one of said parts comprises a .
moisture absorbent material enclosed by said cover sheet.

7. The pad of claim 6, wherein said absorbent material comprises wood pulp inpregnated with starch polymer.

8. The pad of claim 6, wherein said absorbent material com-prises wood pulp impregnated with an acrylic based polymer.

9. The pad of claim 6, wherein said one of said parts further comprises a diffuser layer situated within said absorbent material.

10. The pad of claim 9, wherein said diffusion layer has a plurality of corrugations therein.

11. The pad of claim 10, wherein said corrugations extend in a direction substantially perpendicular to said compression seal.