US2964040A

US2964040A - Absorbent product

Info

Publication number: US2964040A
Application number: US599407A
Authority: US
Inventors: William H Ashton; Edward A Morse
Original assignee: Personal Products Co
Current assignee: Personal Products Co
Priority date: 1956-07-23
Filing date: 1956-07-23
Publication date: 1960-12-13
Anticipated expiration: 1977-12-13
Also published as: NL234994A; GB862185A; GB862186A

Description

Dec. 13, 1960 I w. H. ASHTON ETAL ABSORBENT PRODUCT 2 Sheets-Sheet 1 Filed July 23 1956 Dec. 13, 1960 w. H. ASHTON EIAL 2,964,040

ABSORBENT PRODUCT Filed July 23, 1956 2 Sheets-Sheet 2 INV yoga gr M144 J 0 5411419014. M255 TTO NEY.

ABSORBENT PRODUCT William H. Ashton, Philadelphia, Pa., and Edward A. Morse, Rahway, NJ, assignors to Personal Products Corporation, a corporation of New Jersey Filed July 23, 1956, Ser. No. 599,407

16 Claims. (Cl. 128-290) This invention relates to sanitary napkins and more particularly to sanitary napkins of improved form and of improved fluid absorbency and fluid retentivity characteristics.

Conventional sanitary napkins are generally rectangular in shape and include an elongated core of absorbent fibrous material covered with a fluid permeable wrapper whose ends extend beyond the ends of the core to provide tabs for securing the napkin in position on the body of the wearer. Since these napkins are of a flat, rectangular shape, it is'necessary that, in use, they be bent transversely into a curved shape to conform them to the contours of the female pubic area. In addition, because the napkin is generally wider than the space between the legs adjacent the female pubic region, the napkin generally becomes longitudinally folded with the edge portions of the napkin extending downwardly.

The dimensions of the pad portion of a typical conventional napkin are approximately three-quarters of an inch thick by two and three-quarters inches wide by seven and one-half inches long. In actual use, however, the napkin does not retain its original form because it is necessary to force the flat-shaped pad into one of an arcuate shape to conform it to the curvature of the body area. In so bending the pad, a series of corrugations and folds are formed on the napkin surface adjacent the body. These corrugations and ridges prevent the desired intimate contact between the napkin and that portion of the body of the wearer where a snug fit is necessary for proper functioning of the napkin. In addition, to cause the flat napkin of conventional form to assume an arcuate shape and to retain such shape, tension must be applied to the sanitary belt to which the napkin is customarily attached. This produces discomfort.

The fluid retentivity and absorption characteristics of conventional napkins also are affected by the requirement that the napkin be distorted to fit the female pubic area. Distorting the napkin results in compression of certain portions thereof, thereby reducing the ability of the napkin, and particularly the compressed portions, to absorb and retain fluid and often causing absorbed fluid to be squeezed out, thus wetting adjacent body surfaces.

In accordance with this invention, there is provided a sanitary napkin having a stabilized arcuate shape generally approximating the arcuate shape of the exterior female pubic area to which it is applied, thereby permitting the napkin to be worn comfortably. It is not required, as with napkins of conventional shape, to distort the napkin of the invention to make it conform to the configuration of the pubic area. The longitudinal and transverse corrugations and ridges resulting from deforming conventional napkins are avoided. An additional advantage of the napkin resides in its fluid absorbency and retentivity characteristics. The napkin of the invention contemplates interior constructions which confine absorbed fluid to a selected area and impede its penetrating through to the sides and the lower surface of the napkin. The napkin of the invention also includes exterior tes Patent constructions which provide softness, thereby .nn'nimizing irritation which may arise due to rubbing and chafing, thus making the napkin more comfortable to wear. The napkin also includes improvements relating to attaching it in position.

In the accompanying drawings:

Fig. 1 is a side view of the napkin illustrating the position of a suitable pinning strip for attaching the napkin;

Fig. 2 is a view of the napkin of Fig. 1 as seen from above;

Fig. 3 is an isometric view of the napkin, cut away to reveal its inner construction;

Figs. 4, 5 and 6 are sectional views on an enlarged scale of Fig. 1 taken in the direction of planes 7, 8 and 9, respectively;

Fig. 7 is a top view of a multi-ply pad from which the napkin may be formed;

Fig. 8 is a side elevation of the pad of Fig. 7; and

Fig. 9 is an isometric view of the pad illustrated in Figs. 7 and 8, showing the manner in which the pad may be formed prior to being formed into a napkin.

Referring to the drawings, there is shown a napkin 10, generally of an elongated shape to cover the area between the labia majora and the anus, having front and rear ends it and 12 respectively which are relatively broad in Width, as best seen in Figs. 4 and 6, .and a center portion 13 which is somewhat narrower, as shown in the section in Fig. 5. By tapering the. napkin inwardly from the ends toward the center, the napkin will fit comfortably between the legs and buttocks. The center portion of the napkin is thicker than the end port-ions to provide maximum absorbency in the region where it is needed. In thickness, the end portionsof the napkin are, as seen in Fig. l, tapered so that the ends will lie flat against the body and merge smoothly with adjacent body surfaces to eliminate bulges. Preferably, the front end is slightly thicker than the rear end.

The napkin has an arcuate shape approximating that of the exterior female pubic area Where .it is positioned, thereby eliminating the formation of ridges and corrugations, especially in the transverse direction as has been experienced heretofore with conventional napkins. By providing the napkin with such arcuate shape, the napkin can be placed in intimate contact with the body without resorting to deformation of the napkin, as required with conventional napkins.

To secure the napkin in position for use, a pinning or carrier strip 14 is attached to the bottom of and extended beyond the ends of the napkin to provide front and rear attach-

ing tabs

15 and 16. The pinning strip may be any of the materials found suitable heretofore possessing sulficient strength to bear the stresses imposed during use. Pinning strips of gauze or a nonwoven fabric are satisfactory. The strip may be adhesively secured throughout the entire length of the napkin or only at the ends 11 and 12 thereof.

To provide fluid absorbency and to retain fluid in the interior, the napkin is provided with an elongated core 17 of absorbent fibers, such as comminuted wood pulp fibers, disposed in the center and preferably extending throughout substantially the entire length of the napkin. Other fibers may be used, such-as cotton linters, rag waste and absorbent cotton, but cornniinuted wood pulp fibers are preferred because they are highly absorbent, inexpensive and readily available. To confine absorbed fluid in the interior of the napkin, the bottom surface and longitudinal edges of the absorbent core are covered with a water repellent film or'layer 18. As fluid strikes the upper surface ofnthe napkin,

it penetrates rapidly into the interior, whereupon it is retained and confined in the absorbent core due to the water repellent layer 18. The area on the surface of the napkin upon which fluid normally impinges is small compared to the overall surface area of the napkin with the result .that'the napkin becomes saturated rapidly in the moistened area. When this occurs, fluid contacting the water repellent layer is spread in the absorbent core towards the end of the napkin, thereby more fully utilizing the absorbing effectiveness of the core. The water repellent layer also prevents fiuid absorbed by the napkin from striking through to the sides and bottom of the napkin and wetting adjacent body surfaces. A film of polyethylene approximately two mils in thickness has been found particularly suitable. Other Water repellent materials may be used, such as paper treated to make it water repellent, to provide the barrier effect. By using a film of polyethylene or similar thermoplastic material to provide the fluid barrier in the interior of the napkin, added form stability of the napkin may be obtained. Polyethylene, and like thermoplastic materials, soften when heat is applied and, when softened, may be molded into other shapes. One method of making the napkin of the invention described below includes heating of the polyethylene film during the forming stage in which event the film contributes to the structural stability of the napkin.

The core of absorbent fibers and the water repellent film are enveloped by a relatively thick outer fibrous layer 19, preferably containing absorbent fibers, to impart softness to the napkin so that it may be comfortably worn. Outer layer 19 is made sufficiently thick and fluify to cover the absorbent core 17 and the water repellent film 18 to prevent the film from contacting the body and causing irritation due to chafing and rubbing.

The napkin has an outer wrapper 20 of a fluid pervious material which preferably conforms closely to the shape of the napkin. Stockinet material made of cotton or rayon yarn has been found particularly suitable as an outer wrapper in that it is of an open mesh structure, thereby permitting fluid to pass through readily, and is extensible and elastic, thereby permitting it to stretch, or contract, as necessary, to conform to the configuration of the napkin. The absorbent portion of the napkin may be placed into a tube of such stockinet material Whose length is slightly longer than the length of the absorbent portion of the napkin, and the ends 21 of the stockinet material tucked under the bottom surface of the napkin adjacent the ends 11 and 12, as illustrated in Figs. 1 and 2. The adhesive material used to attach the pinning strip to the underside of the napkin may also be used to attach the folded ends of the stockinet wrapper in position. Other fluid pervious materials may be used if desired, such as knitted fabrics, woven fabrics or nonwoven fabrics. Knitted fabrics, or fabrics possessing similar extensibility characteristics, are preferred because they can be made to conform to the napkin shape to provide a smooth surface, free of folds and wrinkles.

As has been experienced with conventional napkins, the efficiency of a napkin and the protection it provides will be unsatisfactory if the napkin is not maintained in intimate contact with the body. To obtain the desired intimate contact with conventional napkins, it has been necessary to deform the napkin to the shape of the pubic area by applying tension to the belt to which the napkin is attached. The tension required often causes the belt to slide on the body and produces discomfort. By positioning the pinning strip 14 on the bottom of the napkin and extending it along its length and beyond the ends thereof to provide the attaching tabs, at better suspension of vtlhe napkin and a more comfortable, intimate fit between the napkin and the body is obtained. When a napkin having a pinning strip so located is attached to a belt or otherwise secured in position, the forces exerted on the pinning

tabs

15 and 16 are distributed through the pinning strip to the underside of the napkin. By underslinging the napkins pinning strip in this manner, the napkin can be held in intimate contact with the adjacent body surfaces so that the advantages present in the napkin due to its configuration and construction will be fully utilized. r

The napkin of the invention is structurally stabilized in that it retains its arcuate shape without support. Structural stability may be obtained by' incorporating into the napkin fibers which are heat or solvent activatable with fibers which are nonactivatable. The nonactivatable fibers, preferably absorbent cotton or rayon, are homogeneously mixed with the fibers which are heat or solvent activatable. Other satisfactory nonactivatable fibers include Wood pulp fibers, absorbent paper tissue and mixtures thereof.

The activatable fibers include fibers which fuse or tackify when heat isapplied or when treated with solvents, such as the copolymer of vinyl chloride and vinyl acetate, polyvinyl chloride, cellulose ethers or esters such as cellulose acetate. To supplement and facilitate the action of the heat and/or solvent on the activatable fibers, a suitable plasticizer is generally incorporated. For cellulose acetate fibers, dimethyl phthalate mixtures of ortho and para-N-ethyl-toluene sulfonamide and methyl phthaL yl-ethyl glycollate are satisfactory plasticizers and may be added in amounts of from about 10 to about 40 percent or amounts sufficient to tackify the fibers under activating conditions. The required activation of cellulose acetate fibers having the foregoing amounts of plasticizer content may be obtained by heating the fibers to a temperature of from about 140 to about 330 F.

The activatable materials need not necessarily be of the type which fuse or tackify when heated. Materials, such as the polyam-ides, polyesters, polyacrylates and heat settable vinyl polymer fibers, which shrink when heated, may also be used. Further, nonactivatable fibers, such as cotton or rayon fibers, may be coated with a solu tion or an emulsion of a thermoplastic or thermosetting resin of the type described above, thereby providing fibers which may be activated to form the napkin. These coated fibers may be mixed with untreated nonactivatable fibers.

To obtain the mechanical strength desired to impart structural stability to a napkin containing thermoplastic fibers, such as the copolymer of vinyl chloride and vinyl acetate, the range by Weight of such fibers may be from about 15 to about 40 percent and the remaining amounts consisting of cotton or rayon. However, smaller amounts of thermoplastic fibers may be effective, particularly when used in conjunction with a bonding resin. In the interest of economy, inasmuch as activatable fibers are generally more costly, the copolymer of vinyl chloride and vinyl acetate is maintained preferably to about 25 percent. Incorporating greater amounts of such fibers does not ordinarily provide a napkin whose strength is markedly superior and may affect the absorbing properties of the napkin.

Structural stability may also be imparted to the napkin in other ways. For example, the napkin may be sprayed with a suitable bonding resin, such as polyvinyl alcohol dispersed in Water, and then molded to the desired shape by heating to activate the resin.

The napkin of the invention may be prepared from a multi-ply structure of the type illustrated in Figs. 7, 8 and 9. The laminate consists of the thick, fiuify, fibrous bottom layer 19, approximately eight and one-half inches wide, ten and one-half inches long and Weighing from about five to six grams, of carded homogeneously mixed fibers of absorbent cotton or rayon and suitable heat or solvent activatable fibers, such as that of the copolymer of vinyl chloride and vinyl acetate. The layer contains about 75 percent absorbent cotton or rayon and 25 percent of the vinyl copolymer. The thin sheet of polyethylene film 18, about two mils thick, three and onehalf inches wide and six and three-quarters inches long, is placed centrally upon the upper surface of the layer of fibers 19. The thick layer of absorbent fibers 17, such as disintegrated wood pulp fibers weighing about six grams which forms the core of the napkin, is then placed upon the polyethylene film 18. The layer may be about the same length as the ployethylene film upon which it is placed, and approximately two inches wide.

After the laminate has been formed, the

longitudinal edges

22 and 23 of the bottom layer of fibers 19 are brought upwardly around the polyethylene film and fibrous absorbent core and overlapped on the top surface thereof, as seen in Fig. 9, thus enveloping the polyethylene film and absorbent core. In bringing the longitudinal edges of the fibrous layer up around the film and core and overlapping the edges on top, the

longitudinal edges

24 and 25 of the polyethylene film are also brought upward along the adjacent sides of the edges of the absorbent core, thus covering the absorbent core on the bottom and side edges. The laminate is then heated dielectrically to heat the interior of the laminate until the polyethylene film starts to soften and the wood pulp fibers adjacent the film begin to adhere to it. It is nextplaced into a mold heated to 220 F. of the desired configuration and the mold closed and heated, or otherwise operated to produce the desired activation of the activatable fibers, to form the napkin into the stabilized arcuate shape. As the mold is closed, suitable cutting devices may be incorporated with the mold to cut the ends of the laminate during the mold closing .operation. After the napkin has been molded into the desired form, it is removed from the mold, covered with the wrapper 20 and the pinning strip 14 attached to complete the napkin.

While in the foregoing there has been shown and described an illustrative embodiment of the invention, it is to be understood that changes in the details of construction, combinations and arrangements of the parts may be resorted to without departing fiom the scope and spirit of the invention.

We claim:

1. A sanitary napkin comprising absorbent material, said napkin having apreformed acruate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin being tapered inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core, a water repellent layer covering the bottom and sides of said core, a soft fibrous layer enveloping said repellent layer and core, said fibrous layer containing a .bonding agent bonding said fibers to structurally stabilize said napkinin said arcuate shape, a fluid pervious outer wrapper, and a pinning strip secured to the underside of said napkin and extending beyond the ends thereof to provide tabs for attaching said napkin.

'2. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin tapering iwnardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent fibrous core, a layer of water repellent plastic material covering the bottom and sides of said core, a soft layer of absorbent fibrous material enveloping said film and core, said fibrous layer containing a bonding agent bonding said fibers to structurally stabilize said napkin in said arcuate shape, an outer wrapper of stockinet material, and a pinning strip of nonwoven fabric secured to the underside of said napkin and extending beyond the ends thereof to provide tabs for attaching said napkin.

3. A sanitary napkin comprising absorbent material,

said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin being tapered inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core, a water repellent layer covering the bottom and sides of said core, a soft fibrous layer containing bonded activatable fibers enveloping said repellent layer and core, a fluid pervious outer wrapper, and a pinning strip secured to the underside of said napkin and extending beyond the ends thereof to provide tabs for attaching said napkin, said napkin being structurally stabilized in said arcuate shape.

4. A sanitary napkin according to claim 3 wherein said activatable fibers are thermoplastic fibers.

5. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin tapering inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core of wood pulp fibers, a water repellent thermoplastic film covering the bottom and sides of said core, a soft layer of absorbent fibrous material containing bonded activatable fibers enveloping said film and core, an outer wrapper of fluid pervious, conforming material, and a pinning strip secured to the underside of said napkin and extending beyond the ends thereof to provide tabs for attaching said napkin, said napkin being structurally stabilized in said arcuate shape.

6. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin tapering inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated core of wood pulp fibers, a thin water repellent plastic film covering the bott-"m and sides of said core, a thick, soft layer of absorbent fibers and bonded activatable fibers enveloping said film and core, an outer wrapper of stockinet material, and a fabric pinning strip secured to the underside of said napkin and extending beyond the ends thereof to provide tabs for attaching said napkin, said napkin being structurally stabilized in said arcuate shape.

7. A sanitary napkin comprising absorbent material, said napkin having an arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin tapering inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin-having an elongated absorbent fibrous core, a thin polyethylene film covering the bottom and sides of said core, a soft layer comprising from about to about 60 percent by Weight of absorbent fibers and from about 15 to about 40 percent by weight of vinyl chloride-vinyl acetate fibers enveloping said film and core, an outer wrapper of fluid pervious conforming fabric, and a pinning strip attached to the underside of said napkin and extending beyond the ends thereof to provide tabs for attaching said napkin, said napkin being structurally stabilized in said arcuate shape.

8. A sanitary napkin comprising absorbent material, said napkin having an arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin tapering inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core of wood pulp fibers, a thin polyethylene film covering the bottom and sides of said core, a soft layer comprising from about 85 to about 60 percent by weight of absorbent fibers and from about to about 40 percent by weight of vinyl chloride-vinyl acetate fibers enveloping said film and core, an outer wrapper of stockinet material, and a pinning strip attached to the underside of the napkin and extending beyond the ends thereof to provide tabs for attaching said napkin, said napkin being structurally stabilized in said arcuate shape.

9. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin being tapered inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core, a water repellent layer covering the bottom and sides of said core, a soft fibrous layer of bonded fibers enveloping said repellent layer and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said napkin being structurally stabilized in said arcuate shape.

10. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin being tapered inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core, a water repellent layer covering the bottom and sides of said core, a soft fibrous layer enveloping said repellent layer and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said fibrous layer containing a bonding agent bonding said fibers to structurally stabilize said napkin in said arcuate shape.

11. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin tapering inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent fibrous core, a layer of water repellent plastic material covering the bottom and sides of said core, a soft layer of absorbent fibrous material enveloping said film and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said fibrous layer containing a bonding agent bonding said fibers to structurally stabilize said napkin in said arcuate shape.

12. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia maiora to the anus, said napkin being tapered inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core, a water repellent layer covering the bottom and sides of said core, a soft fibrous layer enveloping said repellent layer and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said napkin containing a bonding agent structurally stabilizing said napkin in said arcuate shape.

13. A sanitary napkin comprising absorbent material; said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin being tapered inwardly from a relatively greater width at its ends to a relatively smaller width at its center to fit comfortably in said area, said napkin having an elongated absorbent core, a water repellent layer covering the bottom and sides of said core, a soft fibrous layer enveloping said repellent layer and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said napkin containing bonded activatable fibers structurally stabilizing said napkin in said arcuate shape.

14. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin having an elongated absorbent core, a water repellent layer covering the bottom of said core, a soft fibrous layer enveloping said repellent layer and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said fibrous layer containing a bonding agent bonding said fibers to structurally stabilize said napkin in said arcuate shape.

15. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin having an elongated absorbent core, a water repellent layer covering the bottom of said core, a soft layer of absorbent fibrous material enveloping said repellent layer and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said fibrous layer containing bonded activatable fibers to structurally stabilize said napkin in said arcuate shape.

16. A sanitary napkin comprising absorbent material, said napkin having a preformed arcuate shape approximating that of the exterior female pubic area to cover said area from forward of the labia majora to the anus, said napkin having an elongated absorbent core, a water repellent layer covering the bottom and sides of said core, a soft fibrous layer enveloping said repellent layer and core, and a fluid pervious outer wrapper, said napkin having tabs for attaching said napkin, said fibrous layer containing bonded thermoplastic fibers to structurally stabilize said napkin in said arcuate shape.

References Cited in the file of this patent UNITED STATES PATENTS 1,123,314 Kojima Jan. 5, 1915 1,192,439 Luellen July 25, 1916 1,222,899 Smith Apr. 17, 1917 2,526,125 Francis Oct. 17, 1950 2,774,128 Secrist Oct. 24, 1950 2,549,982 McKahann et al. Apr. 24, 1951 2,566,325 Ganz Sept. 4, 1951 2,697,678 Ness et al Dec. 21, 1954 2,815,027 Makela Dec. 3, 1957 FOREIGN PATENTS 352,805 Great Britain July 16, 1931