US 3688771 A
A tabless sanitary napkin having on its lower surface a pressure-sensitive adhesive suitable for attaching the napkin to an undergarment, and a dual function protective cover removably secured to the adhesive. The cover is an elongate strip of flexible material of a length sufficient to extend beyond both ends of the napkin and thus provide free end tabs. At the option of the user, the protective cover may be retained in place and the free end tabs used as means to suspend the napkin from sanitary belts or similar suspension devices, or the cover may be stripped off and the pressure-sensitive adhesive used as means to fasten the napkin to a suitable undergarment. A method of fabricating a prefolded cover strip and attaching it to the napkin is also disclosed.
Description (OCR text may contain errors)
Werner 1 Sept. 5, 1972 I SANITARY NAPKIN WITH CONVERTIBLE ATTACHMENT MEANS  Inventor: Edward E. Werner, Oshkosh, Wis.
[7 3] Assignee: Kimberly-Clark Corporation, Neenah, Wis.
 Filed: June 3, 1971  Appl. No. 149,441
 U.S. Cl. ..l28/290 R, 156/289  Int. Cl ..A6lf 13/16  Field of Search ..-128/287, 288, 289, 290, 291
 References Cited UNITED STATES PATENTS 2,742,903 4/1956 Lightner 128/290 R 2,38,048 6/1958 Kowalski 128/290 R 2,964,040 12/ 1960 Ashton et a1 128/290 R 2,964,041 12/1960 Ashton et a1 ..128/290 R 3 ,O44,467 7/1962 Campau 1 28/ 290 R 3,512,530 5/1970 Jones 128/290 R 3,575,175 4/ 1971 McGuire ..128/290 R 3,616,797 11/1971 Campaigne, Jr. et
al ..128/290 W Primary Examiner-Charles F. Rosenbaum AttorneyDaniel J, l-lanlon, Jr., William D. Herrick and Raymond J. Miller ABSTRACT A tabless sanitary napkin having on its lower surface a pressure-sensitive adhesive suitable for attaching the napkin to an undergarment, and a dual function protective cover removably secured to the adhesive. The cover is an elongate strip of flexible material of a length sufficient to extend beyond both ends of the napkin and thus provide free end tabs. At the option of the user, the protective cover may be retained in place and the free end tabs used as means to suspend the napkin from sanitary belts or similar suspension devices, or the cover may be stripped off and the pressure-sensitive adhesive used as means to fasten the napkin to a suitable undergarment. A method of fabricating a prefolded cover strip and attaching it to the napkin is also disclosed.
8 Claims, 10 Drawing Figures PATENTEDSEP 5 m2 SHEET 3 OF 4 FlG .8
SANITARY NAPKIN WITH CONVERTIBLE ATTACHMENT MEANS BACKGROUND OF THE INVENTION Tabless sanitary napkins having pressure-sensitive adhesive means for attaching the napkin to a supporting undergarment are known in the art and several types are presently available on the market. However the use of such napkins is limited to occasions when a suitable supporting garment is being worn. If the prospective user does not choose to wear undergarments which are sufficiently snug to provide the required support for these tabless napkins, or if the napkin is for overnight use when such undergarments are not customarily worn, it is necessary for her to revert to the more conventional type napkin which utilizes end tabs as the attachment means for suspending the napkin from a sanitary belt or similar suspension device.
It is the principal object of the present invention to provide a sanitary napkin with a structure which gives the user the option of wearing the napkin (l) by attaching it to a suitable undergarment by means of pressure-sensitive adhesive, or (2) by suspending the napkin by end tabs from a sanitary belt or other suspension device.
It is a further object of the invention to provide a method of fabricating a prefolded end tab structure and removably securing it to a tabless napkin by means of the above-mentioned pressure-sensitive adhesive in a manner to provide the optional structure described herein.
SUMMARY OF THE INVENTION In accordance with this invention, a tabless sanitary napkin of the type which has on its underside a pressure-sensitive adhesive means for use in attaching the napkin to undergarments, is provided with a dual-purpose strippable protective cover for the adhesive. The dual-purpose protective cover comprises an elongate strip of flexible material removably secured to the napkin by the pressure-sensitive adhesive. The strip is of a length sufiicient to provide free ends capable of extending beyond the extremities of the tabless napkin in a manner to provide attachment tabs. The protective cover strip may optionally be peeled from the napkin or retained in place. The napkin thus is provided with convertible attachment means. When the strip is removed, the exposed pressure-sensitive adhesive is the means used to attach the napkin to a supporting undergarment. When the protective cover strip is left in place the extensions provided by the free ends of the strip are the means used to attach the napkin to a conventional sanitary belt or similar suspension device.
For packaging purposes, the free ends of the protective cover strip may be folded to overlap each other below the napkin or the free ends may be folded around the napkin extremities to overlie the face of the napkin.
The arrangement in which the free ends are folded over each other and disposed underneath the napkin is the preferred embodiment since the fabrication of a napkin with such an arrangement is more easily adapted to mechanization.
The following steps describe a suitable method of fabricating the napkins having the dual-purpose protective strips of this invention.
There is first provided a continuous web of lightweight flexible material treated on at least one side with a release coating and having a width equal to the length desired in the finished strip. Second, conventional folding means are used to inwardly fold the edges of the web over each other in overlapping relationship to obtain a continuous folded web of a width which is preferably somewhat less than the napkin length. Third, the folded web is transversely cut into narrow strips whose narrow dimension is preferably somewhat less than the napkin width. In each of these narrow strips the edges which were overlapped during the web folding operation now form the free ends of the folded 5 strip. Fourth, a supply of tabless napkins having a pressure-sensitive adhesive applied to the underside thereof are provided. With the adhesive side of the napkin facing upward, these napkins are moved sequentially past a device for receiving and positively holding the folded and cut strips and for serially feeding the strips into contact with the adhesive. This device is arranged to receive the strips disposed in a manner wherein the release coated face of the strip opposite from the face covered by the overlapping free ends is placed into contact with the pressure-sensitive adhesive previously applied to the underside of the napkin. The napkin with the folded strip removably adhered thereto is now ready for packaging.
In one variation of the described method the pressure-sensitive adhesive may be applied to the strip before attaching it to the napkin rather than applying the adhesive to the napkin first. Upon pressing the preprinted strip against the napkin, the pressure-sensitive adhesive will selectively adhere more strongly to the napkin surface than to the face of the strip because of the release coat treatment of the latter. Accordingly, if the strip is removed from the napkin the adhesive will have transferred to the napkin surface to provide the necessary pressure-sensitive attachment means.
When the consumer uses the finished product, she may elect either to remove the cover strip if it is desired to adhere the napkin to a supporting garment by means of the pressure-sensitive adhesive, or alternatively leave the strip in place if it is desired to suspend the napkin from a sanitary belt or the like by means of the free ends of the still-attached strip.
As indicated above, the protective cover strip should, of course, be provided with a release coating in at least those areas which are in adhering contact with the pressure-sensitive adhesive in order that when the user elects to remove the strip it may be peeled away without destroying the tack of the adhesive or causing portions of the strip to adhere to the adhesive.
The cover strip may be made of woven gauze, of non- -woven web material as further defined hereinafter, or
of any lightweight flexible fabric suitably coated with and/or have laminated on one side a release material for contact with the adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:
FIG. 1 is a perspective view of the underside of a sanitary napkin made in accordance with this invention.
FIG. 2 is a perspective view of the underside of the FIG. 1 napkin with the dual-purpose protective strip partially peeled back.
FIG. 3 is a perspective view of the bottom of a sanitary napkin similar to FIG. 2 but with the protective strip partially broken away to show a different adhesive pattern.
FIG. 4 is a perspective view showing the position of a napkin which has been fastened to a panty by the pressure-sensitive attachment means.
FIG. 5 is a side view of the napkin of FIG. 1 with the free ends of the dual-purpose protective strip unfolded and extended to full length.
FIG. 6 is a plan view of the napkin of FIG. 5.
FIG. 7 is a side view of a napkin with the free ends of the dual-purpose strip folded over the face of the napkin.
FIG. 8 is a schematic and perspective view of a device suitable for use in one method for folding and attaching the dual-purpose strip to a napkin.
' FIG. 8A is a section taken through 8A-8A of FIG. 8.
FIG. 9 is another schematic and perspective view of a device suitable for applying the adhesive to the dualpurpose strip first and subsequently attaching it to a napkin.
DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment of the invention, FIGS. 1 and 2 are perspective views of the underside of a sanitary napkin l3. Sanitary napkin 13 comprises a conventional absorbent pad enclosed in a fluid pervious wrapper. The wrapper is tucked and sealed at each end 14 and 15 adjacent the extremities of the pad whereby a basically tabless napkin structure is provided. In this embodiment, the underside of napkin 13 has applied thereto pressure-sensitive adhesive in the form of parallel lines 16 and 17. An elongate strip of flexible material 18 having free ends and 21 folded over each other in overlapping relationship and a central non-folded portion 22 is disposed in adhering contact with the adhesive on the underside of the napkin, with the adhesive lines 16 and 17 covered by central portion 22. In FIGS. 1 and 2 the overlapping ends 20 and 21 of strip 18 are shown as being partially opened from their normal flat overlapping position on the pad. The face of the central non-folded portion 22 of the strip which is in contact with the pressure-sensitive adhesive has its adhesive contacting portion treated to provide easy release.
FIG. 3 shows a similar pad arrangement as FIG. 2 but with the dual-purpose strip 18 partially broken away. In this embodiment adhesive lines 16a and 17a are interrupted and broken into segments rather than being continuous lines as in FIGS. 1 and 2.
If the napkin shown in FIGS. 1-3 is to be worn in a manner whereby an undergarment such as a panty serves as the support means, the folded protective strip 19 is peeled off and the napkin 13 may then be attached to a panty garment 22 as shown in FIG. 4.
In FIGS. 5 and 6, the sanitary napkin of FIG. 1 is shown in a side and plan view respectively, with the free ends 20 and 21 of dual-purpose strip 18 opened out from their folded configuration. When free ends 20 and 21 are extended in this manner they may then be used as fastening strips whereby the napkin 13 may be pinned to a garment or-threaded through fasteners on a sanitary belt or other suspending device. The strip therefore is utilized to suspend the otherwise tabless napkin in a conventional manner. The pressure-sensitive adhesive 16-17 in such instances serves to keep the strip 18 attached to the underside of the napkin I3 in order that the strip may provide the necessary means of support when its free ends are attached to a suspension device. v
FIG. 7 shows a sanitary napkin in which the free ends 20 and 21 of strip 18 extend around the extremities of the napkin l3 and are folded over the top surface. In this embodiment the free ends 20 and 21 are used to cover and protect the body-contacting surface of the pad from inadvertent soilage before use.
The perspective and schematic illustration of FIG. 8 shows portions of a device which may suitably be used to carry out a method for forming and then attaching the folded version of the dual-purpose strip to napkins. A web 24 of flexible material having a width equal to the desired length of the finished strip is supplied from roll 26. The outer face of at least the non-folded central portion 25 of the web is previously treated with a suitable release material. Web 24 is then passed through a pair of conventional folding boards 27 and 28 suitable for folding web edges 29 and 30 into over-lapping relationship. As shown, the folded web is dimensioned to have a width somewhat less than the length of the napkin to which it is to be subsequently applied. The folded web which at line 8A--8A has its folded edges facing upwardly is passed around turning rolls 3] and 32 whereby the outer surface of the release treated central portion 25 of the folded web is positioned to face upward while the overlapping edge portions 29-30 of the folded web are oriented to face downward. In this position, the folded web is then cut transversely at regular spaced intervals by vertically reciprocating blade 36 or other suitable means into narrow folded strips 34 having a width less than the napkin width. As shown in the finished product, this narrow width dimension of the strips is preferably considerably less than the width of the napkin. The individually severed narrow folded strips 34 with the free end portions oriented to face downward are then deposited at predetermined intervals onto a rotatable vacuum drum 37 where the overlapped folded portion is held in positive contact with freshly drum surface by internally supplied vacuum. Drum 37 with the folded strips 34 held in place by vacuum then rotates to deposit each folded strip in periodic timed sequence onto the pads 13 carried bottom up in longitudinal orientation on cleated belt 39, and to press the folded strips into adhesive association with the adhesive lines 16 and 17 previously applied to the underside of pads 13 by suitable means. Rotating vacuum drum 37 should, of course, be synchronized in timed association with the movement of the spaced pads 13 carried on conveyor belt 39. As the strip is pressed in place on the napkin the vacuum is released and the finished product is carried away on the conveyor belt.
It will be noted that in the folding operation shown in the drawings,'the web edges are first folded upwardly to provide the overlapping fold. Alternatively the folding boards may be arranged to fold the edges downwardly whereby the over-lapped portion is originally oriented to face downward and the indicated reversal of sides is not required before severing the folded strips from the web to deliver them in the correct attitude to. the vacuum drum for subsequent handling.
In FIG. 9 there is shown another arrangement for folding and attaching strips to the napkins of this invention. In this arrangement the pressure-sensitive adhesive is applied directly to the web after folding and before cutting the web into narrow strips preparatory to adhesively attaching the strips to the individual napkins.
As shown in the drawing, web 24a is first folded to the desired width in a manner similar to that previously described. In this instance, the overlapped edge portions of the web are arranged as shown at 29a and 300, that is, with edge 30a disposed on top at the start. The folded web is passed around backup roll 40 which roll also cooperates with adhesive printing roll 41 to form a printing nip. The outer face of the unfolded central portion 25a of the folded web 240 is, of course, pretreated with a release coating as indicated earlier. Printing roll 41 is provided with a series of circumferentially spaced, axially extending lands 42 and 43 which are utilized to print lines of adhesive 16b and 17b at desired spacings on the release-treated central portion 250 of folded strip 24a. A suitable adhesive 44 in the form of an emulsion or other liquid is provided in vat 45, which is shown having its front wall cut away. Metering roll 46 picks up the adhesive 44 from vat 45 and supplies it to transfer roll 47. Roll 47 transfers the adhesive in a predetermined amount to land areas 42 and 43 of printing roll 41. The amount of adhesive is suitably controlled by adjusting the gap of nip 48, or by doctoring the adhesive to a controlled thickness on the surface of metering roll 46 by a doctor blade, not shown. The web 24a carrying the freshyl applied adhesive lines 16b and 17b on its release surface 25a next passes around turning roll 49 from where it is fed to a vertically reciprocating blade 36a or other suitable cutting means which cuts the web 240 transversely into narrow folded strips 340. The individually severed strips 340 with the overlapped portions oriented to face downward are then deposited at predetermined intervals on a rotating vacuum drum 37a so that the overlapped side is held in positive contact with the drum surface by internally supplied vacuum. Drum 370 with the folded strips 34a firmly held in place by vacuum then continues to rotate and deposits each folded strip in timed sequence onto pads 12 where attachment is obtained by simultaneously releasing the vacuum and pressing the strips in place. After the folded strip carrying the adhesive is pressed against the underside of the pads the adhesive will adhere more strongly to the pad than to the strip because of the release treatment of the latter. Thus if the user decides to remove the strip the adhesive will remain on the wrapper surface.
When an aqueous emulsion is employed, merely pressing the cover strip in place is sufficient to obtain attachment. No additional drying is required. When this procedure is used, it was found that the wet adhesive penetrates the pad wrapper and provides attachment between wrapper and pad as well as providing the desired pressure-sensitive surface when the cover strip is removed.
In this embodiment instead of having the pads supplied on a carrier belt in the form of individually finished napkins 13 as in FIG. 8, the pads 12 are fed for service by the vacuum drum while being carried within the wrapper 50 in continuous tubular form. After the strips have been applied to the wrapper enclosing the pads, the tubular wrapper with pads serially spaced therein has its side edges tucked in by a suitable mechanism not shown, and is then cut transversely between the individual pads and the tucked in wrapper is simultaneously or subsequently sealed at the cut ends to provide the finished products.
While this invention is applicable to any type of tabless sanitary napkin, it is especially applicable to the newer type flushable pads. Such napkins comprise a water-dispersible core of absorbent material wrapped in a lightweight fluid-pervious non-woven fiber web bonded by a water-soluble or readily water-dispersible binder. For disposal in a toilet such pads may merely be dropped into the water of a toilet bowl. If the dual-pun pose strip has been used as the suspension means, it should of course first be stripped from the napkin and disposed of separately. Alternatively, the dual-purpose strip may also be made water dispersible, whereby it, too, may be disposed of by flushing.
It will also be seen that the convertible arrangement of a dual-purpose strip and pressure-sensitive adhesive can be used with napkins of unitary structure such as a napkin comprised entirely of absorbent sponge material including cellulose sponge, hydrophilic polyurethane sponge, and the like.
In addition to the parallel continuous or discontinuous lines of adhesive shown in the preferred embodi ments of the drawings other arrangements of adhesive patterns may be used. Included in such arrangements are the use of a single wide line of adhesive, multiple patches of adhesive arranged at the ends or center of the napkin, two-sided adhesive tapes and innumerable other styles.
The protective strip itself may comprise woven webs, non-woven bonded fiber webs, non-woven thread webs, thread reinforced non-woven webs, polyethylene films, other plastic films, or laminates of the above and other materials. It should of course be lightweight and strong, as well as soft and non-abrasive. It should have a good hand and if plastic is used should be plasticized sufficiently to avoid rustling sounds when in use.
As indicated earlier, the strip should also be provided with a release coating in at least that surface area which is in adhering contact with the pressure-sensitive adhesive. Silicones and various fluorochemicals, as well as plastic films with easy release surfaces are suitable for this purpose.
In one preferred embodiment, the web used for the strip comprised an openwork non-woven thread scrim bonded at the thread intersections and having a strip of thin polyethylene film laminated to the central portion for release purposes.
The adhesive used may comprise any of the large number presently available on the market. Such pressure-sensitive adhesives are normally based on an elastomer selected from natural or synthetic rubbers, e.g. pale crepe rubber, smoked sheets, reclaimed rubber, Buna-S and Buna-N type rubbers, polyisoprene, polyisobutylene; and synthetic elastomers such as polyvinyl ethers, polyacrylates or the like. The adhesive mass may be especially compounded or inter-polymerized to provide the balance of adhesiveness characteristic of pressure-sensitive adhesives in general. Aqueous emulsions and hot melt types may be used. Any of the conventional tackifiers such as rosin, dehydrogenated and hydrogenated rosin, polyterpenes, coumaroneindene resins, polyalkyl styrene and the like may be used in proportions well known in the art. Other ingredients, fillers, antioxidants and pigments may also be included in the adhesive mass if desired.
What is claimed is:
l. A sanitary napkin structure with convertible attachment means; said napkin structure comprising an elongate tabless absorbent element having disposed on a portion of its undersurface pressure-sensitive adhesive means; said adhesive means being covered by a removable elongate strip of flexible material disposed in adhering contact with said adhesive; said strip being provided with a release surface in at least that area which is in contact with said adhesive; and said strip having free end portions of a length sufficient to extend beyond each of the extremities of said absorbent element, whereby when said strip is retained in place said free end portions serve as end tabs for attaching said napkin to a sanitary belt or similar suspension device and when said strip is removed said adhesive serves as means for attaching said napkin to an undergarment.
2. The sanitary napkin structure of claim 1 in which the free end portions of said strip are folded over each other in overlapping relationship.
3. The sanitary napkin structure of claim 1 in which the free end portions of said strip are disposed to extend around the extremities of said absorbent element and cover the upper face of said element.
4. The sanitary napkin structure of claim 1 wherein said strip of flexible material is selected from the group consisting of woven webs, non-woven bonded fiber webs, non-woven thread webs, thread-reinforced nonwoven webs, thin plastic films and combinations thereof.
5. The sanitary napkin structure of claim 1 wherein said absorbent element comprises a water-dispersible absorbent core enclosed in a water-dispersible fluidpermeable wrapper.
6. The sanitary napkin structure of claim 5 wherein said wrapper comprises a non-woven web of fibers bonded by a water-soluble adhesive.
7. The sanitary napkin structure of claim 1 wherein said absorbent element comprises an absorbent sponge material.
8. The sanitary napkin structure of claim 1 wherein the release surface of said flexible material which is in contact with said adhesive comprises a thin plastic film laminated to said material.