US2464640A - Sanitary napkin - Google Patents

Description

March l5, 1949.

c. A. FouRNEsS SANITARY .NAPKIN Patented Mar. l5, 1949 Charles Albert Fourness, Appleton, Wis., assigno'r l to International Cellucotton Products Company, a corporation of Delaware Application May Z5, 1945, Serial No. 595,667

claims.l (o1. 12s- 290) l Y 'I'he main object of the invention is to provide a sanitary napkin in which a major portionv of its capacity for iiuid absorptionvwill be effectively utilized. Other objects are'to 'provide effective control of penetration and direction of fluid absorption in a sanitary napkin; to, provide a sanitary napkin with improved softness and comfort` characteristics, and adequate and effective cloth; ing protection features; and to provide a sanitary napkin structure ofthe character indicated which may be economically producedv by fast operating automatic machinery.

In general, it is the object provide an improved sanitary napkin, and other objects and advantages of the invention will be Fig. 3 isa longitudinn section of the une :Q -a

ofthe invention to of Fig. 1, the wrapper being however shown in its normal closed condition.

The vimproved napkin structure'vherein. illusy trated embodies an absorbent pad body 4 covered on its opposite faces with a creped tissue paper backed thin layer of cotton `5. The opposite side edges ofthe pad areembraced by strips 6 which may include `several plies of tissue paper of which at least one ply, usually the innermost ply, i. e. the ply next,v to the edge of the pad 4, is waterproofed. The outer surfaces ofthe edge covering strip 6 may, if desired, be covered with a thin iilm of cotton fibers (not shown). The pad structure is enclosed in the usual gauze wrapper l which has end extensions forming attachment tabs in the usual manner.

The absorbent pad body 4 comprises outer sections 8, 8 which are formed of a plurality of plies sage of fluid from one side of the absorbent pad body to the other side thereof. Such means con sists in this instance of a so-called equalizer element I0 which may be of the construction shown in Heitmeyer Patent No. 1,863,333. That construction consists of a pluralityof plies of creped tissue paper pressed together in transversely spaced longitudinally extending narrow zones which produce capillary tracks for guiding the direction of uid absorption. In association with the equalizer element `Ill there is provided'in this instance a bafile strip I l which may consist of one or more tissue paper plies sized with paramn or other material to render it resistant to the passage of uid therethrough. In some instances the equalizer element l0 may itself be sized or formed of waterproof or water resistant paper so as to constitute a baie rather, than an equalizer, the baille strip Il being then omitted.

The outer sections 8, 8, are somewhat longer than the inner sections as best shown in Fig. 3 and the end portions of said section beyond the ends of theintermediate sections 9, 9, are pressed together to unite said end portions substantiallyy vas explained in Glomstead Patent No. Re. 21,076.

The inner sections of the pad are thereby clamped together and frictionally held in place and vthe pad provided with thinned, at, body-hugging end portions. 1 I

In fabricating the structure, the duif sections tissue vwrapper stripsbeing drawn from-supply *l rolls and combined with the fluff layers by guiding the traveling layers and saidstrips into the desired relationship. The wrapper strip would, of course, be folded around the width of the overlapped fluii. layers and baille and equalizer strips,

margins of thewrapper being preferably over- 1 lapped as shown at i3.

of absorbent creped tissue paper. Inwardly ofv the creped/tissue paper sections 8, 8 are sections 9, 9 of very loosely felted fibrated wood pulp maf The Wrapped iiui, baiile and equalizer web vstructure thus formed is then fed between wider l supply strips of absorbent creped tissue paper and between tissue backed cotton covering strips. End portions ofthe assembled strips corresponding to the width ofthe sanitary napkin are then cut fromthe assemblage and the cut off units enclosed in the edge strips 6, 6 and gauze wrapper 1 by suitable mechanism.

The mechanism for making the pads forms no part of the present invention and is, therefore, not shown or described.

In the described 'napkin structure there is a considerable improvement over prior pad structures in that a much larger portion of the absorbent pad body is actually caused to absorb fluid which is delivered to a localized area at one side of the napkin.

y This improvement appears to be due to different absorption characteristics of the outer creped tissue paper layers of the pad and the adjacent inwardly disposed fluff layers of the pad. The` creped tissue outer layers have a pronounced tendency to quickly absorb fluid deposited thereon in a localized area and to quickly spread the absorbed iiuid lengthwise of the creped tissue layer. This is probably due to the multiplicity ofiv capillary tubes formed by the creping of the tissue paper plies. It will of course beunderstood that in accordance with more or less common practice, the direction of creping in the creped tissue paper sections is such that the capillary tubes extend lengthwise of the pad. Thus the intermittently deposited fluids encountered in menstruation are quickly spread along the length of the napkin so as to avoid a tendency to the formation of an over-wet localized area of fluid application.

The ui layers have a very high capacity for fluid absorption but they have a less pronounced tendency to spread the area of absorption in any specic direction. Absorption generally spreads more or less uniformly in all directions from any given point of fluid application, this being probably due to the haphazard arrangement of the fibers forming the fluff material. Also it appears that the fluff material requires a somewhat'longerl time period for the absorption of a given quantity of fluid than does the creped tissue material so that absorption progresses more slowly in the fluff material than in the creped material.

The fluid deposited on the'surface of the pad first spreads laterally, predominanty lengthwise, in the creped tissue section of the pad on which the uid was deposited, and gradually penetrates saidtsection to reach the adjacent fluff section. When the tissue section of the pad is lled and penetrated by the absorbed uid, the fluid will be transferred to the adjacent fluff layer over most of the area of the latter rather than to any small localized area corresponding to the localized area in which fluid is deposited on the outer creped tissue sections.

The fluff section, although being somewhat slower than the creped tissue section to absorb fluid, acts to absorb fiuid over a well spread area so that it is not required to absorb fluid at the same rate of speed as the creped tissue section in order to prevent the accumulation of free fluid inl the tissue section. This wide spread area of absorption results in effective utilization of most of the area of both the tissue and the fluff section so that most of the absorbing capacity of the said sections is utilized with the result that penetration of the entire thickness of the said sections requires an extended period of time under average conditions of menstruation.

The centrally disposed equalizer and baille elements serve to effect internal spreading of the area of absorption throughout the length of the fluil layer on one side of the equalizer and baille before fluid can penetrate through the equalizer and baille elements to enter the fluff layer on the other side thereof.

The baille element il is so formed that it will strongly resist the passage of fluid through it until such time that the absorbent material on one side thereof is so loaded with uid that the fluid exerts such pressure as to wet and penetrate the baille element. The equalizer element lll may serve its usual internal absorption distributing function and should of course be located on the side of the pad (with reference to the bame element) which is worn next to the body.

The equalizer and baille elements are'desirable as a safety measure against the passage of fluid from any localized area on one side of the pad directly through the pad to the other side thereof. This precaution is not essential in the employment of the invention but it is desirable because the repeated, localized application of fluid on one side of the napkin necessarily has a tendency to produce excessive wetness in one area which correspondingly tends to cause penetration of the pad in such localized area. Also,I the folding of the napkin and shaping thereof to the body and perhaps other causes, sometimes produce localized areas of accelerated penetration. Also, the provision of the equalizer element, whether or not sized so as to resist absorption, is desirable although not necessary, because of its body giving effect in the pad.

Because of the increased utilization of the absorptive capacities of the absorbent pad, and because of theV fact that absorption is drawn inwardly from th'e outer layers over most of the area of the pad, it is found that the napkin has an improved tendency to maintain its outer surfaces dry to add to the comfort characteristic of the napkin. The napkin may therefore be worn for av much longer` period than has been practi- I cable with constructions heretofore available.

in an all-creped tissue paper pad, while at the same rtime providing a pad with sufficient body to hold its size and form, thereby avoiding the usual criticism against pads made entirely of dun material. The increased cross softness is probably due to the elimination of resistance to bending which is inherent in a multiple-ply all-laminated structure. In the described structure, the multiple-ply laminated outer sections `8, 8 are separated from each other -so that they offer much less resistance to bending than would the same number of plies laminated together in a single Y unit.

Another important advantage of the described construction is that it results in a napkin `having exceptionally soft, non-chaflng edges. The softn ness occurs because of the fact that the crepe tissue and equalizer layers of the pad are elastic and under some tension at the time that the pad unit is cut from the yweb of` material which is formed as above explained. The fluff layers are, however, relatively inelastic. When the pad unit is cut from the web of material, the tissue and equalizer layers, being under some tension, shrink back somewhat into the pad after the shearing while the fiu layers, being relatively'inelastic, are left extending suflciently to provide the desired soft edge.

In the described arrangement,A the pad is reversible; that is to say, the pad may be worn with either side next to the body. This eliminates the necessity of supplying instructions as to the proper wearing of the pad together with the necessity for marking the pad to indicate which side should be worn next to or away from the body. Such instructions and markings are often completely overlooked, or misunderstood with resulting complications. Nevertheless, because of the eilective use made of most of the area of the pad, and the delayed penetration of the equalizer and baille strips, there is a negligible danger of A strike-through in the described composite pad construction. Thus full absorbing capacity of the absorbent material is employed while at the same time attaining substantial prevention of complete penetration of the pad.

Various changes in the described structure may be made without departing from the principles of the invention.

1. A sanitary napkin embodying an elongated absorbent pad and a pervious wrapper enclosing the same, said pad comprising a layer of fiu, and a layer of relatively superposed plies of creped tissue paper disposed in overlying relation to said fluff layer on the body side of the pad, said tissue and fluff layers each representing a substantial portion of the thickness oi the pad and said tissue layer having a iluid absorbing rate and, as an incident to its thickness, a fluid absorbing capacity, which enable the tissue layer to retain a considerable volume of absorbed iluid and to rapidly diffuse fluid absorbed from a localized area of uid application on said layer, whereby the pad is given the characteristic o'f initial uid absorption mainly in said tissue layer and delayed transmission of iluid from said tissue layer to said fluir layer, absorption strikethrough being thereby delayed.

2'. A sanitary napkin embodying an elongated absorbent pad and a pervious wrapper enclosing the same, said pad comprising a layer of fluff, and a layer of relatively superposed plies of creped tissue paper of a width no greater than the width of said iiui layer, said tissue layer being disposed in overlying relation to said fluir layer on the body side of the pad with the side edges of said tissue layer located within the width of said 11u11! layer, said tissue layer representing a substantial portion of the thickness of the pad and having a fluid absorbing rate and, as an incident to its thickness, a uid absorbing capacity, which enable the tissue layer to retain a considerable volume of absorbed iiuid and to rapidly diiIuse iluid absorbed from a localized area of iluid application on said layer whereby the pad is given the characteristic of initial iluid absorption mainly in said tissue layer and delayed transmission of iluid from said tissue 'layer to said sorbing capacity thereof incident to its thickness,

being such as to enable the tissue layer to retain a considerable volume of absorbed fluid and to rapidly diffuse iluid absorbed from a localized y. area of uuid application thereon, whereby the pad isgiven the characteristic of initial fluid absorption mainly in said tissue layer and delayed ion oi' fluid from the same to said nui! layer, absorption strike-through being thereby greatly delayed.

4. A reversible sanitary napkin comprising an elongated absorbent pad and a pervious wrapper enclosing said pad, said pad being of laminated construction having a pair of outer layers each consisting of a plurality of plies of creped tissue paper, and a filler comprising a layer of fiui intermediate said tissue layers, said tissue layers being of a width no greater than the width o! said iiuii layer and being disposed within the width oi' said ui layer, said tissue layers being of approximately equal thickness and the total thickness of said tissue layers and the thickness of said iiller representing approximately equal fractions of the thickness of the pad, the fluid absorbing rate of each of said tissue layers and its uid absorbing capacity incident to its thickness being such as'to enable each tissue layer to retain a considerable volume of absorbed fluid and to rapidly diffuse iluid absorbed from a localized,

area of uid application thereon, whereby the pad is given the characteristic of initial iluid absorption mainly in a tissue layer and vdelayed transmission of iluid from the same to said filler, absorption strike-through being thereby greatly delayed.

5. A reversible sanitary napkin comprising an elongated absorbent -pad and a pervious wrapper enclosing said pad, said pad being of laminated construction, and having a pair of outer layers each consisting of a plurality of plies of creped tissue paper, a pair of inner layers of iiuff respectively disposed in face-to-face contact with the l inner faces of said outer layers, and fluid penetration resistant means intermediate said inner layers, said tissue layers and said ilui layers being of substantially like thickness, the uid absorbing rate of each of said tissue layers and the iluid absorbing capacity thereof incident to its thickness being such as to' enable each tissue layer to retain a considerable volume of absorbed fluid and to rapidly diiuse iiuid absorbed from a localized area of uid application on the outer face thereof, whereby the pad is given the characteristic of initial fluid absorption mainly in a tissue layer andl delayed transmission of iluid fromthe same to the adjacentilui layer, said uid penetration resistant means serving to resist the transfer of absorbed fluid from one iui layer to the other, absorption strike-through being thereby greatly delayed. CHARLES ALBERT FOURNESS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,857,854 Glomstead May 10,' 1932 1,863,333 Heitmeyer June 14, 1932 1,910,872 Williams May 23, 1933 v 2,024,976 Mathey et al Dec. 17, 1935 2,067,961 Williams Jan. 19, '1937 2,073,591 Shaefler Mar. 9, 1937 2,296,341 Fourness Sept. 22, 1942 l FOREIGN PATENTS Number Country Date 535,916 Great Britain Apr. 25, 1941

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