US 3060936 A
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Description (OCR text may contain errors)
A. A. BURGENI SANITARY NAPKIN Oct. 30, 1962 2 Sheets-Sheet 1 Filed Oct. '7, 1958 [IE l] DIME Oct. 30, 1962 A- A ,BURGENl y SANITARY NAPKIN Filed OCb. 7, 1958 2 Sheets-Sheet 2 A TORNEY 3,060,936 SANITARY NAPKIN Alfred A. Burgeni, Short Hills, NJ., assigner to Personal Products Corporation, a corporation of New .lersey Filed Get. 7, 1958, Ser. No. 765,786 Claims. (Cl. 12S-290) This invention relates to absorbent products and more particularly to absorbent products especially suitable for use as disposable pads for catamenial purposes.
Absorbent pads of the type used for catamenial purposes are usually relatively bulky and flat and rectangular. In use, they are subjected to squeezing and distorting forces which, due to the size and shape of the pads, cause them to deform and to bend transversely to assume an l inverted U shape. Such distortion is undesirable because after being distorted, the pad does not readily adapt itself to changes in body contours during movement. These forces and the resultant distortion also reduce the absorbing effectiveness of the pad. The problem is pronounced where the absorbent pad has an absorbent core containing loosely integrated fibrous material, as for example where the core contains predominantly short fibrous material, such as Wood pulp bers or cotton linters. Cores 'of this type are not inherently resilient and springy and lack form stability and shape retention. They tend to mat readily, particularly when wetted, and do not spring back appreciably to maintain lContact with the body. It is necessary, therefore, to include other components in a pad containing a core of this type to provide it with these characteristics.
I have found that absorbent pads containing such cores can be made springy and resilient and be made stable with good form and structural stability by providing the core with a cover of fluid pervious material which extends over the top and down the sides and at least partially across the bottom of the core where it is secured and by further providing a springy, resilient layer on the bottom of the core so that the pad will tend to spring back in use after being distorted. The forces which tend to deform the absorbent pad are resisted by Ithe cover and the underlayer. Springiness, resilience and resistance to deformation may be imparted to the core by extending the edges of the cover across the bottom of the core in overlapping relationship, or by providing a separate layer or layers of springy, resilient material on the bottom surface of the core, and extensively bonding the material underlying the core to the core.
An important feature of my invention is the provision of a disposable absorbent pad suitable for use as a sani- 'tary napkin which has a springy, resilient layer of material, preferably liquid repellent, on the underside thereof which is integrated with the core whereby the core and the springy, resilient layer mutually contribute to 'impart springiness and resiliency to the pad. My invention also contemplates an inexpensive absorbent pad obtained through the use of inexpensive materials wherein the inexpensive materials may be used in certain portions of the pad without detracting from its absorbing effectiveness. Another feature of my invention is the provision of a pad containing a core of loosely integrated brous material which normally tends to separate readily but which is confined within the cover, the ends of the pad being closed or nearly so by compacting and densitying the fibers in the core at the ends.
Reference is made to the accompanying drawings and the following specification, wherein various embodiments of the invention are illustrated and described by way of example.
In the drawings:
FIG. 1 is a perspective View of an absorbent pad suitable for catamenial purposes incorporating the invention;
3,9%,936 Patented ct. 30, 1962 FIG. 2 is a bottom View of the pad of FIG. l illustrating the manner in which the cover, backing sheet and core may be associated;
FIG. 3 is a sectional view of FIG. 2 along lines 3-3;
IG. 4 is a sectional View of another form of pad incorporating the invention;
FIG. 5 is a view of the pad attached to a strip for holding the pad in position on the body of the wearer;
FIG. 6 is a side View of FIG. 5; and
FIG. 7 is another form of holding strip with which the pad may be utilized.
Referring to the drawings, a pad l0 embodying the invention includes an elongated core of absorbent material l2, such as core of comminuated wood pulp fibers, cotton linters, or other suitable material, covered with a liquid pervious material 14, such as a non-Woven fabric, on the top, sides and partially on the bottom. The longitudinal side edges 16 of the covering material extend under the bottom of the core a short distance inwardly towards its longitudinal axis to provide marginal edge portions extending the length of the core on each side thereof.
The bottom of the core is covered with a backing sheet 18 which limparts springness, resiliency and resistance to deformation to the pad, especially transversely. lf desired, a material which is dierent from the covering material may be used. In this manner, materials which are less expensive than the covering material, and materials having different physical characteristics may be used. The material used as the backing sheet is preferably a sheet of liquid repellent paper which is relatively stiff, springy and resilient and deformation resistant in com- .parison to the core and the covering material so that these characteristics will be imparted to the core and the cornpleted pad.
The respective components arranged as described above would shift with respect to each other and would not be retained in their respective positions in use. To integrate the structure, the cover and backing sheet are attached to the absorbent core and in one form of the invention, also to each other.
As illustrated in FIGS. 2 and 3, the cover and the backing sheet are so dimensione-d that the side edges of each overlap on the bottom of the core -to provide marginal portions which extend the length of the pad. The side edges of the cover are arranged in overlapping relationship with the side edges of the backing sheet by positioning the side edges of the cover under the side edges of the backing sheet and in contact with the core of absorbent material.
The cover and the backing sheet are attached to the core by moistening or applying an adhesive material to one surface of the core, placing the cover and the backing sheet over the core with the overlapping marginal portions of lthe cover and the backing sheet on the moistened side of the core and then subjecting the cover, backing sheet and the core in the moistened portions to suflicient compression to bond the components or, Where moisture is used, to cause the formation of hydrate-bonds between fibers in the moistened and compressed areas. The compression need not extend completely and be continuous over the face of the pad, but is desirably limited to a patterned or intermittent compression whereby only portions of the pad are subjected to compression While the remaining parts are relatively uncompressed.
A suitable pattern, illustrated in FIGS. 2 and 3, is one which is intermittent in nature and may consist of a series of spaced, offset, rows of compressed areas 20 extending along the length of the pad. A row 22 of compressed areas is positioned at the overlapping marginal portions of the cover and the backing sheet to join them together. The marginal portions ofthe cover are placed next to the core so that it will be bonded directly to the core. Satisfactory bonding may be obtained by employing a patterned compression roller which forms compressed areas on the bottom of the pad about 3 millimeters wide and about 2 millimeters long and spaced about 4 millimeters apart. @ther :bonding patterns may be used and the bonding may be obtained by means other than by the use of moisture and pressure, as by employing suitable adhesives, resins, thermoplastic materials, and the like.
By attaching the cover and the backing sheet to the absorbent core as described above, the absorbent core, the cover, and the backing sheet mutually contribute to each other in imparting form and structural stability to the pad and the physical characteristics of resiliency, springiness and the like. For example, when the pad so formed is subjected to the normal squeezing forces er1- countered in use, as in the case of a sanitary napkin, it tends to assume an inverted U shape due to its coniiguration. The top of the pad is subjected to tension and the bottom of the pad to compression. By anchoring the side edges of the cover to the bottom of the core, the pad tends tol return to its undistorted shape. Thus, the core and cover are retained in relatively iixed position with respect to each other during transverse deformation. Springiness, resiliency and resistance to transverse deformation into a U shape are provided by the backing sheet, which is also attached to the bottom of the core and, in one form of the invention, to the side edges of the cover whcih overlap the side edges of the backing sheet. A material suitable for a hackingsheet has a high elasticity and resiliency and good springiness and resistance to compression, and may be a two ply sheet of paper Weighing approximately 12 pounds per 2880 sq. ft. and impregnated with a water repellent material such as aluminum rosinate.
The backing sheet is extensively secured or bonded to the absorbent core throughout a large portion of their adjacent surfaces to prevent the backing sheet from buckling and separating from the absorbent core when the pad yis subjected to deformation. If the backing sheet separated from the core during deformation, it would not impart its springy and resilient characteristics to the pad with the result that the pad would not tend to return to its original shape. If desired, one or more plies of other material, such as one or more plies of absorbent tissue paper may be positioned on the back of the core to provide further resiliency and elasticity. Diiferent types of materialmay also be used in various combinations, as for example by covering the bottom of theI core With a laminate of springy, resilient repellent paper positioned between plies of absorbent paper tissue.
In the form of the invention illustrated in FIG. 4, the side edges of the cover and the backing sheet overlap on the lbottom of the, core. However, in thisform, the cover and the backing sheet are not attached to each other at their marginal portions as in the embodiment described above in connection with FIGS. 1 through 3. Instead, themarginal portions 22 of the cover are attached tothe core a short distance inwardlyV from its side edges while the backing sheet is attached extensively to the core, as above. Y
A disposable absorbent padY incorporating the invention vmay be made in the following manner. AA continuous web of comminutedV wood pulp about two andY ve-eighths inches wide -andweighing about 1350 grains per-squarefoot is formed by any well known operation. The surface of the web which ultimately forms the bottom ofthe pad is sprayed witha fineV spray of water ito provide aY moisture pick upof approximately 60 grains of water per one hundred square inches ofV web area. By spraying with aiine'spray of water'infthe amounts indicated, the moisture is limited in application to the surface of the web andappreciable amounts of the moisture do not penetrate into the interior ofthe web. After spraying with moisture, a liquid pervious fabric, such as a non-woven fabric weighing approximately 220 grains per square yard is applied to cover the top, sides and a portion of the bottom surface of the web to which the moisture has been applied. The side edges of the cover may extend over the side edges of the moistened surface of the web to form marginal portions about nine-sixteenths of an inch wide extending the length of the web, leaving an uncovered por-tion approximately one and one-half inches wide extending centrally throughout the length of the web. After the cover has been placed around the web the sheet of springy, resilient liquid repellent lpaper sufficiently wide to overlap the edges of the cover is placed over the uncovered portion of the web. The structure so formed is then embossed by passing through a device consisting of a patterned embossing roller and a smooth surfaced backing roller with the patterned roller embossing the side of the web covered with repellent paper. Suiiicient pressure is applied by the embossing roller to integrate the respective parts of the pad and to obtain a coherent bond between the core and the repellent paper and the edges of the cover. The formation of the coherent bond due to the presence of moisture and the application of pressure unites the respective elements.
If desired, the product so formed may be supplied in continuous lengths, e.g. as a roll of suicient length to provide ten to twelve individual pads which may be cut as needed. Preferably, individual pads are cut during the manufacturing operation with rounded ends 24 as illustrated in the drawings. During the cutting operation, the ends of the pads and the iibers in the core at the ends are densiiied and compacted to form at least a partial closing of the ends, thus minimizing separation of the ii-brous material at the ends of the pad. The cutting operation, which may be performed with a reciprocating cutter and which may be conducted in the presence of the moisture sprayed on the surface of the web, results in the application of compression to the ends of the piece being cut which causes a fusion or welding of the iibers in the ends of the pad.
The pad may be used as a disposable catamenial insert by inserting into a panty, or it may be used as a complete napkin. In FIGS. 5 through 7, there are illustrated carrier strips which may be used to support the pad to form a complete napkin ready for use. In FIG. 5, there is shown a strip of fabric 26 such as a strip of 5gauze approximately 1 inch wide and 14 to 16 inches long which serves as carrier for the pad. The pad is positioned on the top of the carrier strip so that the ends of the carrier strip extend beyond the ends of the pad to provide attaching tabs. The pad is maintained in position on the carrier strip by adhesive tabs v28, such as tabs formed from pressure sensitive adhesive tape, having a portion thereof which is adhesively secured to the surface of the carrier strip and the remaining portion adhered to the top end 'surface of the absorbent pad. This form of carrier strip is especially suitable for use with pads having repellent paper in the bottom because repellent paper does not stick readily to conventional'adhesive masses. Better adhesion in such cases is obtained'by adhering the ladhesive tabs to the cover on the top ofthe pad. In FIG. l7, instead of adhesive tabs, the carrier strip is provided with spacedradhesive surfaces 30 which are so positioned on the carrier strip as to adhesively contact the absorbent pad placed upon the strip adjacent the ends ofthe pad thereby securing the pad to the carrier strip. This form of carrier strip is suitable for useV with pads which have backing sheets which adhere readily to adhesive masses. It is to be understood that variations and changes may made in the above described illustrative embodiments of the invention. For example, one or more-layers of materials may be added or substitutedvin different combinations with the components of the pad and that such" variations and changes are contemplated as withinl the invention.
What is claimed is:
l. A sanitary napkin comprising a thick, elongated rectangular-shaped absorbent member having spaced, parallel, longitudinally extending side edges, said member including a core containing loosely integrated short absorbent ibers, a liquid pervious cover covering the top and sides of said core and extending at least partially under the bottom thereof, the longitudinal side edges of said cover being in alignment with the longitudinally extending side edges of said core, said cover being secured at its side edges to said core, and a springy, resilient backing layer covering the bottom of said core, said backing layer being extensively and intermittently secured to said bottom of said core in spaced compressed areas, and maintained in intimate relationship therewith, said member having form stability in said rectangular shape and being deformation resistant transversely.
2. A sanitary napkin comprising a thick, elongated, rectangular-shaped absorbent member having spaced parallel,
longitudinally extending side edges, said member including a core containing loosely integrated short absorbent cellulosic fibers, a liquid pervious cover covering the top and sides of said core and extending at least partially under the bottom thereof, the longitudinal side edges of said cover being in alignment with the longitudinally extending side edges of said core, said cover being secured at its side edges to said core, and a springy, resilient backing layer covering the bottom of said core, said backing layer being extensively and intermittently secured by hydrate bonds to said bottom of said core in spaced compressed areas, and maintained in intimate relationship therewith, said member having form stability in said rectangular shape and being deformation resistant trans- `versely.
3. A sanitary napkin comprising a thick, elongated rectangular-shaped absorbent member having spaced, parallel, longitudinally extending side edges, said member including a core containing loosely integrated short absorbent bers, a liquid pervious cover covering the top and sides of said core and extending at least partially under the bottom thereof, the longitudinal side edges 0f said cover being in alignment with the longitudinally extending side edges of said core, and a springy, resilient backing layer covering the bottom of Said core, the side edges of said cover and said backing layer overlapping, said cover being secured at its side edges to said core and to the side edge of said backing layer, said backing layer 6 being extensively and intermittently secured to said bottom of said core in spaced compressed areas, and maintained in intimate relationship therewith, said member having form stability in said rectangular shape and being deformation resistant transversely.
4. A sanitary napkin comprising a thick, elongated rectangular-shaped absorbent member having spaced, parallel, longitudinally extending side edges, said member including a core containing loosely integrated short ab- `sorbent cellulosic libers, a liquid pervious cover covering the top and sides of said core and extending at least partially under the bottom thereof, the longitudinal side edges of said cover being in alignment with the longitudinally extending side edges of said core, and a springy, resilient backing layer covering the bottom of said core, the side edges of said cover and said 4backing layer overlapping, said cover being secured at its side edges to said `core and to the side edges of said backing layer, said backing layer being extensively and intermittently secured by hydrate bonds to said bottom of said core in spaced, compressed areas, and maintained in intimate relationship ftherewith, said member having form stability in said rectangular shape and being deforma-tion resistant transversely.
5. A sanitary napkin comprising an elongated carrier strip, an elongated, rectangular-shaped absorbent pad on said strip, the ends of said strip extending beyond the ends of said pad forming attachment tabs, and an adhesive tab at each end of the pad, each tab having a portion of its adhesive surface adhering to the surface of said strip beyond the ends of said pad and another portion adhered to the end portion of the adjacent end of said pad at the top surface thereof to maintain said pad in position on said strip.
References Cited in the tile of this patent UNITED STATES PATENTS 860,111 Wright July 16, 1907 1,753,106 Barth Apr. 1, 1930 2,074,936 Paterson Mar. 23, 1937 2,104,423 Hughes Ian. 4, 1938 2,408,508 Canavan Oct. 1, 1946 2,649,858 Le Bolt Aug. 25, 1953 2,742,903 Lightner Apr. 24, 1956 i 2,788,003 Morin Apr. 9, 1957 2,838,048 Kowalski June 10, 1958